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Project Title:  Residence Time Driven Flame Spread Over Solid Fuels--NNX15AG11G Expand All
Images: icon  Fiscal Year: FY 2019 
Division: Physical Sciences 
Research Discipline/Element:
COMBUSTION SCIENCE--Combustion science 
Start Date: 04/06/2015  
End Date: 04/05/2020  
Task Last Updated: 05/03/2019 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bhattacharjee, Subrata  Ph.D. / San Diego State University 
Address:  5500 Campanile Drive, Mechanical Engineering Department 
 
San Diego , CA 92182-0001 
Email: prof.bhattacharjee@gmail.com 
Phone: 619-594-6080  
Congressional District: 53 
Web:  
Organization Type: UNIVERSITY 
Organization Name: San Diego State University 
Comments:  
Co-Investigator(s) / Affiliation:  Miller, Fletcher  Ph.D./ San Diego State University  Paolini, Christopher  Ph.D./ San Diego State University  Takahashi, Shuhei  Ph.D./ Gifu University, Japan  Wakai , Kazunori  Ph.D./ Gifu University, Japan 
Project Information: Grant/Contract No. NNX15AG11G 
Responsible Center: NASA GRC 
Grant Monitor: Olson, Sandra  
Center Contact: 216-433-2859 
Sandra.Olson@nasa.gov 
Solicitation: 2009 Combustion Science NNH09ZTT001N 
Grant/Contract No.: NNX15AG11G 
Project Type: FLIGHT  
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: COMBUSTION SCIENCE--Combustion science 
Task Description: NOTE: Continuation of "Residence Time Driven Flame Spread Over Solid Fuels," grant # NNX10AE03G, Principal Investigator Subrata Bhattacharjee, PhD.

Flame spread over solid fuels in an opposed-flow environment has been investigated for over four decades for understanding the fundamental nature of hazardous fire spread. The appeal for this configuration stems from the fact that flame spread rate remains steady, even if the flame itself may grow in size. For practical fire safety issues, however, wind-assisted flame spread is more relevant.

However, these two regimes have always been studied in isolation without much effort to establish a connection, even though the underlying mechanism of flame spread is the same in all regimes. Sitting between the two regimes are high-residence time flames, as found in a low-velocity or quiescent microgravity environment. Residence time is the time spent by an oxidizer in the combustion zone. Such flames, which are of interest on their own merit due to fire safety issues in spacecraft, offer some unique characteristics because of the high residence time. Radiation becomes dominant and, based on previous space experiments and analysis, we contend that a vigorously spreading flame on Earth becomes self-extinguishing in a microgravity environment under certain conditions such as the fuel thickness being greater than a critical value.

The proposed research uses a comprehensive approach-- a novel experimental set up and a theoretical framework based on scaling and numerical modeling-- to investigate flame spread driven by varying residence time, from blow-off extinction in an opposed-flow configuration through high residence time flame to blow-off extinction in a concurrent-flow configuration. At the heart of this proposal is a novel but simple experiment where the residence time of the oxidizer can be controlled and high residence time flames can be established for a long duration (compared to drop towers). As a proof of concept, we have constructed a flame tower at San Diego State University (SDSU) in which, after a sample is ignited, the sample holder, placed in an open moveable cart, can be traversed at any desired speed upward or downward, creating an external flow that can augment or mitigate the buoyancy-induced flow. Preliminary results show that we can control the residence time and create flames in different regimes, including a transition between a wind-aided and wind-opposed configuration. At Gifu University in Japan, we have been developing an interferometry based imaging system which we intend to enhance to capture the thermal footprint of a flame's leading edge. The leading edge is central to our understanding of mechanism of flame extinction. Further development of this technology will enable us to integrate diagnostics in future space based experiments and provide validation data to a comprehensive numerical model. The comprehensive model, to be built upon our existing two-dimensional model, will solve an unsteady, three-dimensional, Navier stokes equation with finite rate kinetics in the gas and solid phases and radiation in the gas phase. The software implementation will be object-oriented and utilize a new technology called Web Services that will decouple various sub-models and enhance parallel execution.

The radiation model will also be refined by including the equilibrium composition of species for finding radiative properties in high residence-time flames. The comprehensive model, tested against available theory, data in literature, and data generated at SDSU and Gifu, was applied to test the three hypotheses presented in the preceding grant regarding flame extinguishment in a microgravity environment. A successful outcome of that project is leading to a well thought out space-based experiment on the mechanism of flame extinction in a gravity free environment. We have received authority to proceed to Preliminary Design Review.

 

Research Impact/Earth Benefits: Our research has four components. (a) We have built three experimental setups at SDSU: Flame Tower where a test sample can be traversed up or down at any desired velocity; Flame Stabilizer where the motion of the flame can be arrested by moving the sample exactly at the speed of the flame spread in the opposite direction; and a rotating Flame Tunnel where a combustion tunnel can be oriented at any desired angle to study the interaction of buoyancy and forced flow; (b) Theoretical and computational work that explores the similarity and differences between the mechanisms flame spread in a zero gravity space environment and on Earth; (c) Support the space based experiment (in the SoFIE project) to establish extinction mechanism of flames; (d) Develop software tools for data analysis and share those with the research community.

The data that we are acquiring in the experiments provide the research community with a comprehensive set of results for testing different theories of flame spread in a normal gravity environment. Moreover, by controlling the residence time, various regimes of flame spread, including the microgravity regime, can be explored in the Flame Tower. Our theoretical work predicts a fuel thickness beyond which steady flame spread is unsustainable in a gravity free environment. If we are successful in establishing a critical thickness, this will have a powerful impact on making fire resistant environment for humans in space.

As part of this project, we are developing thermodynamic calculators for combustion and equilibrium calculations, which has a significant educational component. These are available to the community through http://www.thermofluids.net . We have also developed a MATLAB based image processing tool named FIAT (Flame Image Analysis Tool), which is now available to the community from http://flame.sdsu.edu .

 

Task Progress & Bibliography Information FY2019 
Task Progress: The tasks we have performed to date can be separated into four different categories. Below, we list the progress we are making in each.

A. Ground-Based Experimental Work: The goal of this work is to establish the role of residence time, time spent by an oxidizer in a flame leading edge, on the mechanism and control of flame spread. Towards this goal, we have been building a number of ground-based experiments involving flame spread over thin solid fuels in an opposed flow environment.

A.1: SDSU Flame Tower: The flame tower is the centerpiece of our ground-based activities. We have finished the construction of a 10 m tall steel chamber (details on year-1 report--FY2011 report for predecessor grant NNX10AE03G) inside which a fuel sample mounted on a cart can be traversed up or down a vertical rail with a prescribed velocity. We have been successful in developing a completely remote controlled system to move a cart at any desired speed (from -3 m/s to + 3 m/s: details in year-2 report, FY2012 report for predecessor grant NNX10AE03G). We have conducted detailed velocity measurement to establish that the flow seen by the flame is uniform upstream over a 40 mm by 40 mm area upstream of the fuel sample (which is 20 mm wide).

The design and operation of the micro flame tracker, which is housed inside the moving cart, has been described in the year-2 report (FY2012 report for predecessor grant NNX10AE03G). Once the flame is ignited, a gas phase thermocouple, attached to a linear motion system on the cart, tracks its motion of the leading edge of the flame, providing the instantaneous flame spread rate. The flame spread is also obtained by analyzing the side-view digital video of the flame, allowing us to verify the data from the automated tracking system.

Data on flame spread rate and flame shape were obtained for flame spread over ashless filter paper with the relative flow velocity varying from positive (opposed flow configuration) to negative (concurrent flow configuration). The spread rate behavior was consistent with theoretical prediction for the opposed flow configuration. When the cart was moved upward (in the same direction of the buoyancy driven flow), the flame spread rate remained fairly constant (or slightly increasing) until about a flow speed of -40 cm/s, when the flame converted itself into its concurrent-flow configuration (wind assisted flame spread). We are still analyzing the wealth of data produced by these experiments.

The flow velocity at which blow-off extinction occurs was found to be sensitive to the development length of the boundary layer. Using an air flow sensor, we characterized the velocity field seen by our moving sample. A detailed study using Fluent was used to relate that cart velocity with the velocity seen by the flame (see previous reporting).

The effect of the flow velocity and the boundary development lengths were experimentally studied using ashless filter paper and the results strongly support an effective velocity correlation that we developed from scale analysis (see details in phase-I, year-4 report).

We have begun new experiments with PMMA (polymethyl-methacrylate) samples. Results of these experiments will be reported in the next year’s progress report.

A.2: Flame Stabilizer: One of the challenges in the experimental study of flame spread is that even if the flame spreads at a steady rate, the propagating flame creates an unsteady phenomenon with respect to the laboratory frame of reference. As a result, it is difficult to obtain detailed data, necessary for validating models, in a spreading flame. To remedy this situation, we have built a novel flame spread apparatus that moves the fuel in the opposite direction of the flame spread to keep the leading edge of the flame stationary with respect to the laboratory. A thermocouple, fixed to the laboratory frame of reference, in front of the leading edge of the flame senses the presence of the flame and a proportional–integral–derivative controller (PID controller) keeps its temperature constant by moving the sample holder, driven by a stepper motor, in the opposite direction at the velocity of the spread. Instantaneous flame spread rate and the visible flame structure are compared for a downward spreading flame over ashless filter paper with the corresponding stationary flame. The results indicate that the difference between the two configurations are within experimental uncertainties and the stabilized flame can represent a spreading flame adequately, including variability of flame spread rate and the flame geometry, for further observation.

We have presented this work in the 34th International Symposium on Combustion. With a spreading flame stabilized by this apparatus, we are in a position to measure gas phase temperature, including in the plume region, where fluctuations due to turbulence makes it very difficult to map out the thermal field of a spreading flame.

Using a K type thermocouple we mapped the gas phase temperature field of a stabilized flame. An infrared CO2 sensor was used to map out the CO2 concentrations.

When the temperature and CO2 concentrations are normalized by their equilibrium values (0 for ambient conditions and 1 for chemical equilibrium values), the similarity between the temperature and CO2 is remarkable (see FY2014 report for predecessor grant NNX10AE03G). Using the fluctuations in the signal, the pseudo-turbulence intensity was calculated for both the temperature and CO2 concentrations showing strong similarity. Turbulence is most intense at the far downstream of the flame and in the outer zone of entrainment.

In the subsequent years we have improved the flame stabilizer by replacing the thermocouple with a radiometer to sense the advancing flame. The data acquisition capabilities now include measurement of thermal radiation and gas phase temperature using S-type thermocouple.

A.3 The Flame Tunnel: We have designed and fabricated a wind tunnel for combustion experiments where we can create a prescribed flow of air over different types of fuel samples (flat or cylindrical). The unique design also allows us to change the orientation of the tunnel making it possible to create downward, opposed-flow, horizontal, and concurrent-flow flame spread. In addition, the angle of the tunnel with the vertical axis can be changed to study effect of inclination on flame spread.

A.4 The Ignition Delay Apparatus: The Burning and Suppression of Solids –II (BASS-II) experiments have generated a wealth of information on ignition time of solid fuels. Yet, almost none of these data have been analyzed. We have built a simple apparatus with the goal of accurately measuring ignition delay time of solid fuels. Two horizontal parallel cylindrical wires (Kanthal) are electrically heated in a symmetric fashion. Once they reach steady state, a sample is suddenly inserted in between the two ignition wires. An infra-red camera monitors the rise in temperature of the fuel and an inflexion point in the rise in temperature, which is followed by ignition, is used to identify the ignition time.

B. Preparation for Space-Based Experimental Work:

We have proposed an experimental matrix in the BASS-II project to that will help us (a) determine a suitable ignition method; (b) select an oxygen level suitable for flame spread over PMMA ; (c) estimate extinction time at lower oxygen level; and (d) evaluate the width effect to supplement our original experimental matrix in the SoFIE project.

Results from BASS-II experiments have been used in several archival journal publications. The results have reinforced our theoretical prediction that below a certain critical velocity, flame extinguishes due to radiative cooling.

C. Theoretical/Modeling Work: We are continuing to make progress in modeling flame spread over solid fuels under different conditions. Our modeling/theoretical effort can be summarized as follows:

1. We have been developing Web based tools for calculating equilibrium temperature of PMMA and Cellulose combustion. This calculation tool, which can be used by the community, helps us determine exactly how much sample burn is possible (under different conditions) in a closed chamber without significantly altering the oxygen level. It also predicts the equilibrium composition providing us with the thermodynamic limits of CO2 level and temperature in the gas phase to be expected.

2. We are using a two dimensional model with finite-rate one-step kinetics, and radiation to simulate opposed flow flame spread. The model has been used to compare downward flame spread results with experiments conducted in the lab. The spread rate from the model for three different fuel thicknesses agreed quite well with the experimental results for downward spread over PMMA sheets under the ambient conditions.

3. The model was used to compare pure downward flame spread with the stabilized flame produced by our stabilizer device. The comparison of the numerical results as well as experimental data established the flame stabilizer does reproduce all the characteristics of a downward spreading flame, only the flame is now frozen in the laboratory coordinate ready for prolonged examination. This study established the flame stabilizer as a new viable platform for experimental studies of flame spread.

4. The data from the flame tower showed that the blow off velocity (of the opposing flow) was related to the boundary layer development length. The computational model, along with scale analysis, was used to quantify the effect of the development length in terms of an effective velocity. An effective velocity for a flame, embedded in a boundary layer, is defined as an equivalent velocity seen by the flame. The effective velocity is then correlated with free stream velocity, development length of the boundary layer, and fluid and fuel properties. The resulting correlations were remarkably accurate in explaining the blow off extinction velocity over a wide range of parametric conditions.

5. We have done detailed radiation calculations to establish the importance of radiation loss versus radiation feedback. Also, the radiation loss correction of thermocouple measurement has been computed taking into account both radiative loss and gain by the thermocouple bead.

6. We have developed a MATLAB based image analysis tool (FIAT (Flame Image Analysis Tool)) that can be used to analyze videos of any flame spread experiment.

D. Space Based Experiments (BASS-II): We have conducted three sets of experiments as part of the BASS-II project, burning twenty samples of PMMA. Computational and theoretical work in support of these experimental results have been published in several archival journal papers. The experimental matrix for the SoFIE experiments has been finalized.

E. Dissemination of Results: We have published a significant number of journal and conference papers, one textbook, and updated our research and outreach websites ( https://www.thermofluids.net , http://flame.sdsu.edu ). The MATLAB based application FIAT (Flame Image Analysis Tool) is available for download from our website flame.sdsu.edu .

 

Bibliography Type: Description: (Last Updated: 06/13/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings Carmignani L, Dong K, Bhattacharjee S. "Influence of oxygen concentration on flame structure and spread in microgravity." 34th Annual Meeting of the American Society for Gravitational and Space Research, Bethesda, MD, October 31-November 3, 2018.

34th Annual Meeting of the American Society for Gravitational and Space Research, Bethesda, MD, October 31-November 3, 2018. , Nov-2018

Abstracts for Journals and Proceedings Chan R, Carmignani L, Bhattacharjee S. "Flame spread in microgravity and critical conditions for radiative extinction." Western States Section of the Combustion Institute (WSSCI) Spring Meeting 2018, Oregon State University, Bend, OR, March 25-27, 2018.

Western States Section of the Combustion Institute (WSSCI) Spring Meeting 2018, Oregon State University, Bend, OR, March 25-27, 2018. , Mar-2018

Articles in Peer-reviewed Journals Carmignani L, Rhoades B, Bhattacharjee S. "Correlation of burning rate with spread rate for downward flame spread over PMMA." Fire Technology. 2018 May;54(3):613-24. https://doi.org/10.1007/s10694-017-0698-3 , May-2018
Articles in Peer-reviewed Journals Delzeit T, Carmignani L, Matsuoka T, Bhattacharjee S. "Influence of edge propagation on downward flame spread over three-dimensional PMMA samples." Proceedings of the Combustion Institute. 2019;37(3):3203-9. https://doi.org/10.1016/j.proci.2018.06.160 , Jan-2019
Dissertations and Theses Keiven KP. (Kenneth P. Keiven) "Experimental Control of Ignition and Flame Spread." Masters, San Diego State University, September 2018. , Sep-2018
Dissertations and Theses Renkes C. (Christoph Renkes) "Effect of Fuel Geometry on Downward Flame Spread Over Thin Fuels." Masters, Universität der Bundeswehr in Munich and San Diego State University, September 2018. , Sep-2018
Dissertations and Theses Kaskir O. (Onur Kaskir) "Experimental Investigation of the Influence of Thickness and Opposed Flow on the Spread Rate Over Thick PMMA Samples." Masters, Universität der Bundeswehr in Munich and San Diego State University, September 2018. , Sep-2018
Dissertations and Theses Arnold P. (Peter Arnold) "Measurement of Temperature Field in Downward Flame Spread Over PMMA." Masters, Universität der Bundeswehr in Munich and San Diego State University, September 2018. , Sep-2018
Dissertations and Theses Chan R. (Ryan Chan) "Effect of Oxygen Concentration on Flame Spread Over Thin Fuels in Different Regimes: A Numerical Investigation." Masters, San Diego State University, February 2018. , Feb-2018
Papers from Meeting Proceedings Delzeit T, Carmignani L, Matsuoka T, Bhattacharjee S. "Influence of edge propagation on downward flame spread over three-dimensional PMMA samples." 37th International Symposium on Combustion, Dublin, Ireland, July 29-August 3, 2018.

37th International Symposium on Combustion, Dublin, Ireland, July 29-August 3, 2018. , Aug-2018

Papers from Meeting Proceedings Carmignani L, Sato S, Bhattacharjee S. "Flame spread over acrylic cylinders in microgravity: effect of surface radiation on flame spread and extinction." 48th International Conference on Environmental Systems, Albuquerque, NM, July 8-12, 2018.

48th International Conference on Environmental Systems, Albuquerque, NM, July 8-12, 2018. ICES paper ICES-2018-311. http://hdl.handle.net/2346/74248 ; accessed 5/9/2019. , Jul-2018

Project Title:  Residence Time Driven Flame Spread Over Solid Fuels--NNX15AG11G Expand All
Images: icon  Fiscal Year: FY 2018 
Division: Physical Sciences 
Research Discipline/Element:
COMBUSTION SCIENCE--Combustion science 
Start Date: 04/06/2015  
End Date: 04/05/2020  
Task Last Updated: 02/04/2018 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bhattacharjee, Subrata  Ph.D. / San Diego State University 
Address:  5500 Campanile Drive, Mechanical Engineering Department 
 
San Diego , CA 92182-0001 
Email: prof.bhattacharjee@gmail.com 
Phone: 619-594-6080  
Congressional District: 53 
Web:  
Organization Type: UNIVERSITY 
Organization Name: San Diego State University 
Comments:  
Co-Investigator(s) / Affiliation:  Miller, Fletcher  Ph.D./ San Diego State University  Paolini, Christopher  Ph.D./ San Diego State University  Takahashi, Shuhei  Ph.D./ Gifu University  Wakai , Kazunori  Ph.D./ Gifu University 
Project Information: Grant/Contract No. NNX15AG11G 
Responsible Center: NASA GRC 
Grant Monitor: Olson, Sandra  
Center Contact: 216-433-2859 
Sandra.Olson@nasa.gov 
Solicitation: 2009 Combustion Science NNH09ZTT001N 
Grant/Contract No.: NNX15AG11G 
Project Type: FLIGHT  
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: COMBUSTION SCIENCE--Combustion science 
Task Description: NOTE: Continuation of "Residence Time Driven Flame Spread Over Solid Fuels," grant # NNX10AE03G.

Flame spread over solid fuels in an opposed-flow environment has been investigated for over four decades for understanding the fundamental nature of hazardous fire spread. The appeal for this configuration stems from the fact that flame spread rate remains steady, even if the flame itself may grow in size. For practical fire safety issues, however, wind-assisted flame spread is more relevant.

However, these two regimes have always been studied in isolation without much effort to establish a connection, even though the underlying mechanism of flame spread is the same in all regimes. Sitting between the two regimes are high-residence time flames, as found in a low-velocity or quiescent microgravity environment. Residence time is the time spent by an oxidizer in the combustion zone. Such flames, which are of interest on their own merit due to fire safety issues in spacecraft, offer some unique characteristics because of the high residence time. Radiation becomes dominant and, based on previous space experiments and analysis, we contend that a vigorously spreading flame on Earth becomes self-extinguishing in a microgravity environment under certain conditions such as the fuel thickness being greater than a critical value.

The proposed research uses a comprehensive approach-- a novel experimental set up and a theoretical framework based on scaling and numerical modeling-- to investigate flame spread driven by varying residence time, from blow-off extinction in an opposed-flow configuration through high residence time flame to blow-off extinction in a concurrent-flow configuration. At the heart of this proposal is a novel but simple experiment where the residence time of the oxidizer can be controlled and high residence time flames can be established for a long duration (compared to drop towers). As a proof of concept, we have constructed a flame tower at San Diego State University (SDSU) in which, after a sample is ignited, the sample holder, placed in an open moveable cart, can be traversed at any desired speed upward or downward, creating an external flow that can augment or mitigate the buoyancy-induced flow. Preliminary results show that we can control the residence time and create flames in different regimes, including a transition between a wind-aided and wind-opposed configuration. At Gifu University in Japan, we have been developing an interferometry based imaging system which we intend to enhance to capture the thermal footprint of a flame's leading edge. The leading edge is central to our understanding of mechanism of flame extinction. Further development of this technology will enable us to integrate diagnostics in future space based experiments and provide validation data to a comprehensive numerical model. The comprehensive model, to be built upon our existing two-dimensional model, will solve an unsteady, three-dimensional, Navier stokes equation with finite rate kinetics in the gas and solid phases and radiation in the gas phase. The software implementation will be object-oriented and utilize a new technology called Web Services that will decouple various sub-models and enhance parallel execution.

The radiation model will also be refined by including the equilibrium composition of species for finding radiative properties in high residence-time flames. The comprehensive model, tested against available theory, data in literature, and data generated at SDSU and Gifu, was applied to test the three hypotheses presented in the preceding grant regarding flame extinguishment in a microgravity environment. A successful outcome of that project is leading to a well thought out space-based experiment on the mechanism of flame extinction in a gravity free environment. We have received authority to proceed to Preliminary Design Review.

 

Research Impact/Earth Benefits: Our research has four components. (a) We have built three experimental setups at SDSU: Flame Tower where a test sample can be traversed up or down at any desired velocity; Flame Stabilizer where the motion of the flame can be arrested by moving the sample exactly at the speed of the flame spread in the opposite direction; and a rotating Flame Tunnel where a combustion tunnel can be oriented at any desired angle to study the interaction of buoyancy and forced flow; (b) Theoretical and computational work that explores the similarity and differences between the mechanisms flame spread in a zero gravity space environment and on Earth; (c) Support the space based experiment (in the SoFIE project) to establish extinction mechanism of flames.; (d) Develop software tools for data analysis and share those with the research community.

The data that we are acquiring in the experiments provide the research community with a comprehensive set of results for testing different theories of flame spread in a normal gravity environment. Moreover, by controlling the residence time, various regimes of flame spread, including the microgravity regime, can be explored in the Flame Tower. Our theoretical work predicts a fuel thickness beyond which steady flame spread is unsustainable in a gravity free environment. If we are successful in establishing a critical thickness, this will have a powerful impact on making fire resistant environment for humans in space.

 

Task Progress & Bibliography Information FY2018 
Task Progress: We have completed another productive year with vigorous experimental, theoretical, and numerical research in support of the Residence Time Driven Flame Spread (RTDFS) module of the SoFIE project. The major achievements of this period include further analysis of Burning and Suppression of Solids –II (BASS-II) experimental results (obtained from experiments aboard International Space Station-ISS), experiments with fuel of different geometry, publication of three archival journal articles based on these results, and several conference papers.

Luca Carmignani, the Ph.D. student in the Joint Doctoral Program between SDSU and UCSD (University of California-San Diego), is performing a lead role, advising several Masters and undergraduate students while continuing his own research of flame spread. Blake Road and Thomas Delzeit completed their Masters theses. Several Masters students, Ken Kievens, Ryan Chan, Yonatan Dawit, Robert Clay, and Ally Ferrel are at various stages of their research towards their theses. Several undergraduate students are doing their senior design project in our laboratory.

 

Bibliography Type: Description: (Last Updated: 06/13/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings Delzeit T, Carmignani L, Bhattacharjee S. "Influence of Edge Propagation on Downward Flame Spread over 3D PMMA Samples." 33rd Annual Meeting of the American Society for Gravitational and Space Research, Seattle, WA, October 25-28, 2017.

33rd Annual Meeting of the American Society for Gravitational and Space Research, Seattle, WA, October 25-28, 2017. , Oct-2017

Articles in Peer-reviewed Journals Carmignani L, Rhoades B, Bhattacharjee S. "Correlation of burning rate with spread rate for downward flame spread over PMMA." Fire Technology. 2018:1-12. Article First Online: 13 January 2018. https://doi.org/10.1007/s10694-017-0698-3 , Jan-2018
Articles in Peer-reviewed Journals Carmignani L, Bhattacharjee S, Olson S, Ferkul P. "Boundary layer effect on opposed-flow flame spread and flame length over thin polymethyl-methacrylate in microgravity." Combustion Science and Technology. 2018;190(3):535-49. Published online: 14 Nov 2017. https://doi.org/10.1080/00102202.2017.1404587 , Jan-2018
Articles in Peer-reviewed Journals Bhattacharjee S, Carmignani L, Celniker G, Rhoades B. "Measurement of instantaneous flame spread rate over solid fuels using image analysis." Fire Safety Journal. 2017 Jul;91:123-9. https://doi.org/10.1016/j.firesaf.2017.03.039 , Jul-2017
Articles in Peer-reviewed Journals Carmignani L, Bhattacharjee S, Francesco L, Celniker G. "The effect of boundary layer on blow-off extinction in opposed-flow flame spread over thin cellulose: experiments and a simplified analysis." Fire Technology. 2017 May;53(3):967-82. First Online: 22 July 2016. http://dx.doi.org/10.1007/s10694-016-0613-3 , May-2017
Articles in Peer-reviewed Journals Bhattacharjee S, Simsek A, Miller F, Olson S, Ferkul P. "Radiative, thermal, and kinetic regimes of opposed-flow flame spread: A comparison between experiment and theory." Proceedings of the Combustion Institute. 2017;36(2):2963-9. Available online 17 August 2016. http://dx.doi.org/10.1016/j.proci.2016.06.025 , Jan-2017
Dissertations and Theses Delzeit T. (Thomas Delzeit) "Effect of Edge Propagation on Downward Flame Spread over PMMA Samples." Masters Thesis, Universität der Bundeswehr in Münche, August, 2017. , Aug-2017
Dissertations and Theses Rhoades B. (Blake Rhoades) "Experimental Investigation of Relations between Spread Rate and Burning Rate of PMMA." Masters Thesis, San Diego State University, March, 2017. , Mar-2017
Papers from Meeting Proceedings Bhattacharjee S, Carmignani L, Celniker G, Rhoades B. "Measurement of Instantaneous Flame Spread Rate Over Solid Fuels Using Image Analysis" 12th International Symposium on Fire Safety Science, Lund, Sweden, June 12-16, 2017.

12th International Symposium on Fire Safety Science, Lund, Sweden, June 12-16, 2017. , Jun-2017

Papers from Meeting Proceedings Carmignani L, Bhattacharjee S. "Correlating Mass Burning Rate and Flame Spread Rate for Thin PMMA: Implications on Pyrolysis Temperature." Western States Section of the Combustion Institute Fall Technical Meeting 2017, Laramie, WY, October 2-3, 2017.

Western States Section of the Combustion Institute Fall Technical Meeting 2017, Laramie, WY, October 2-3, 2017. , Oct-2017

Papers from Meeting Proceedings Bhattacharjee S, Carmignani L, Rhoades B. "Correlating the burning rate with burn angle for downward flame spread over PMMA." 2017 10th U.S. National Combustion Meeting, College Park, MD, April 23-26, 2017.

2017 10th U.S. National Combustion Meeting, College Park, MD, April 23-26, 2017. , Apr-2017

Papers from Meeting Proceedings Carmignani L, Bhattacharjee S. "Flames: Out of this world." Research Expo 2017, University of California San Diego, April 20, 2017.

Research Expo 2017, University of California San Diego, April 20, 2017. , Apr-2017

Project Title:  Residence Time Driven Flame Spread Over Solid Fuels--NNX15AG11G Expand All
Images: icon  Fiscal Year: FY 2017 
Division: Physical Sciences 
Research Discipline/Element:
COMBUSTION SCIENCE--Combustion science 
Start Date: 04/06/2015  
End Date: 04/05/2020  
Task Last Updated: 01/31/2017 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bhattacharjee, Subrata  Ph.D. / San Diego State University 
Address:  5500 Campanile Drive, Mechanical Engineering Department 
 
San Diego , CA 92182-0001 
Email: prof.bhattacharjee@gmail.com 
Phone: 619-594-6080  
Congressional District: 53 
Web:  
Organization Type: UNIVERSITY 
Organization Name: San Diego State University 
Comments:  
Co-Investigator(s) / Affiliation:  Miller, Fletcher  Ph.D./ San Diego State University  Paolini, Christopher  Ph.D./ San Diego State University  Takahashi, Shuhei  Ph.D./ Gifu University  Wakai , Kazunori  Ph.D./ Gifu University 
Project Information: Grant/Contract No. NNX15AG11G 
Responsible Center: NASA GRC 
Grant Monitor: Olson, Sandra  
Center Contact: 216-433-2859 
Sandra.Olson@nasa.gov 
Solicitation: 2009 Combustion Science NNH09ZTT001N 
Grant/Contract No.: NNX15AG11G 
Project Type: FLIGHT  
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:  
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: COMBUSTION SCIENCE--Combustion science 
Task Description: NOTE: Continuation of "Residence Time Driven Flame Spread Over Solid Fuels," grant # NNX10AE03G.

Flame spread over solid fuels in an opposed-flow environment has been investigated for over four decades for understanding the fundamental nature of hazardous fire spread. The appeal for this configuration stems from the fact that flame spread rate remains steady, even if the flame itself may grow in size. For practical fire safety issues, however, wind-assisted flame spread is more relevant.

However, these two regimes have always been studied in isolation without much effort to establish a connection, even though the underlying mechanism of flame spread is the same in all regimes. Sitting between the two regimes are high-residence time flames, as found in a low-velocity or quiescent microgravity environment. Residence time is the time spent by an oxidizer in the combustion zone. Such flames, which are of interest on their own merit due to fire safety issues in spacecraft, offer some unique characteristics because of the high residence time. Radiation becomes dominant and, based on previous space experiments and analysis, we contend that a vigorously spreading flame on Earth becomes self-extinguishing in a microgravity environment under certain conditions such as the fuel thickness being greater than a critical value.

The proposed research uses a comprehensive approach-- a novel experimental set up and a theoretical framework based on scaling and numerical modeling-- to investigate flame spread driven by varying residence time, from blow-off extinction in an opposed-flow configuration through high residence time flame to blow-off extinction in a concurrent-flow configuration. At the heart of this proposal is a novel but simple experiment where the residence time of the oxidizer can be controlled and high residence time flames can be established for a long duration (compared to drop towers). As a proof of concept, we have constructed a flame tower at San Diego State University (SDSU) in which, after a sample is ignited, the sample holder, placed in an open moveable cart, can be traversed at any desired speed upward or downward, creating an external flow that can augment or mitigate the buoyancy-induced flow. Preliminary results show that we can control the residence time and create flames in different regimes, including a transition between a wind-aided and wind-opposed configuration. At Gifu University in Japan, we have been developing an interferometry based imaging system which we intend to enhance to capture the thermal footprint of a flame's leading edge. The leading edge is central to our understanding of mechanism of flame extinction. Further development of this technology will enable us to integrate diagnostics in future space based experiments and provide validation data to a comprehensive numerical model. The comprehensive model, to be built upon our existing two-dimensional model, will solve an unsteady, three-dimensional, Navier stokes equation with finite rate kinetics in the gas and solid phases and radiation in the gas phase. The software implementation will be object-oriented and utilize a new technology called Web Services that will decouple various sub-models and enhance parallel execution.

The radiation model will also be refined by including the equilibrium composition of species for finding radiative properties in high residence-time flames. The comprehensive model, tested against available theory, data in literature, and data generated at SDSU and Gifu, was applied to test the three hypotheses presented in the preceding grant regarding flame extinguishment in a microgravity environment. A successful outcome of that project is leading to a well thought out space-based experiment on the mechanism of flame extinction in a gravity free environment. We have received authority to proceed to Preliminary Design Review.

 

Research Impact/Earth Benefits: Our research has four components. (a) We have built three experimental setups at SDSU: Flame Tower where a test sample can be traversed up or down at any desired velocity; Flame Stabilizer where the motion of the flame can be arrested by moving the sample exactly at the speed of the flame spread in the opposite direction; and a rotating Flame Tunnel where a combustion tunnel can be oriented at any desired angle to study the interaction of buoyancy and forced flow; (b) Theoretical and computational work that explores the similarity and differences between the mechanisms flame spread in a zero gravity space environment and on Earth; (c) Support the space based experiment (in the SoFIE project) to establish extinction mechanism of flames.; (d) Develop software tools for data analysis and share those with the research community.

The data that we are acquiring in the experiments provide the research community with a comprehensive set of results for testing different theories of flame spread in a normal gravity environment. Moreover, by controlling the residence time, various regimes of flame spread, including the microgravity regime, can be explored in the Flame Tower. Our theoretical work predicts a fuel thickness beyond which steady flame spread is unsustainable in a gravity free environment. If we are successful in establishing a critical thickness, this will have a powerful impact on making fire resistant environment for humans in space.

 

Task Progress & Bibliography Information FY2017 
Task Progress: Significant progress has been made during this period of the project. The major highlight of this period is further analysis of BASS-II experimental results (obtained from experiments aboard International Space Station-ISS) and publication of two archival journal articles based on these results. We also presented several conference papers. In this period we have significantly expanded the capabilities of our Flame Stabilizer apparatus for automated data acquisition. One of our major accomplishment is the publication in the 36th International Symposium on Combustion, the abstract of which is highlighted below (see also Bibliography section):

The three regimes of opposed-flow flame spread – radiative, thermal, and kinetic regimes – are well known. For thermally thin fuels, the spread rate is independent of opposing flow velocity in the thermal regime. It decreases with an increase in the flow velocity in the kinetic regime, leading to blow off extinction. In the radiative regime which occurs mostly in a buoyancy-free environment of microgravity, the spread rate decreases with a decrease in flow velocity leading to radiative extinction unless the oxygen level is very high. In a recent experiment aboard the International Space Station, thin sheets of (Poly(methyl methacrylate) (PMMA) were ignited in a flow tunnel with the opposing flow varying over a wide range. All three regimes of flame spread were captured in a single set of experiments for the first time. Instantaneous spread rates were obtained from digital video processing and compared with a computational model in all three regimes along with the evolution of flame shapes. Spread rates in the radiative and thermal regimes are also compared with existing theories of flame spread in the thermal and the radiative regime producing remarkable qualitative agreement.

 

Bibliography Type: Description: (Last Updated: 06/13/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings Carmignani L, Bhattacharjee S. "Flame Spread over PMMA Samples and Blow-Off Extinction for Different Angles." 32nd Annual Meeting of the American Society for Gravitational and Space Research, Cleveland, OH, October 26-29, 2016.

32nd Annual Meeting of the American Society for Gravitational and Space Research, Cleveland, OH, October 26-29, 2016. , Oct-2016

Abstracts for Journals and Proceedings Carmignani L, Rhoades B, Bhattacharjee S. "Comparison of flame spread and blow-off extinction over vertical and horizontal PMMA samples." 10th Southern California Flow Physics Symposium (So Cal Fluid X), UC Irvine, Irvine, CA, April 2016.

10th Southern California Flow Physics Symposium (So Cal Fluid X), UC Irvine, Irvine, CA, April 2016. , Apr-2016

Abstracts for Journals and Proceedings Lange G, Kievens K, Bhattacharjee S. "Measurement and Computations of Thermal Radiation in Downward Spreading Flame." Western States Section Technical Meeting of the Combustion Institute, Spring Technical Meeting, University of Washington, Seattle, WA, March 21-22, 2016.

WSS Technical Meeting of the Combustion Institute, Spring Technical Meeting, University of Washington, Seattle, WA, March 21-22, 2016. , Mar-2016

Articles in Peer-reviewed Journals Bhattacharjee S, Simsek A, Miller F, Olson S, Ferkul P. "Radiative, thermal, and kinetic regimes of opposed-flow flame spread: A comparison between experiment and theory." Proceedings of the Combustion Institute. In press, corrected proof. Available online 17 August 2016. http://dx.doi.org/10.1016/j.proci.2016.06.025 , Aug-2016
Articles in Peer-reviewed Journals Carmignani L, Bhattacharjee S, Francesco L, Celniker G. "The effect of boundary layer on blow-off extinction in opposed-flow flame spread over thin cellulose: experiments and a simplified analysis." Fire Technology. First Online: 22 July 2016. http://dx.doi.org/10.1007/s10694-016-0613-3 , Jul-2016
Papers from Meeting Proceedings Bhattacharjee S, Carmignani L, Simsek A. "Boundary Layer Effect on Opposed-Flow Flame Spread in the Microgravity Regime." 46th International Conference on Environmental Systems, Vienna, Austria, July 10-14 2016.

46th International Conference on Environmental Systems, Vienna, Austria, July 10-14 2016. ICES paper 2016-387. http://hdl.handle.net/2346/67700 ; accessed 2/1/17. , Jul-2016

Project Title:  Residence Time Driven Flame Spread Over Solid Fuels--NNX15AG11G Expand All
Images: icon  Fiscal Year: FY 2016 
Division: Physical Sciences 
Research Discipline/Element:
COMBUSTION SCIENCE--Combustion science 
Start Date: 04/06/2015  
End Date: 04/05/2020  
Task Last Updated: 02/25/2016 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bhattacharjee, Subrata  Ph.D. / San Diego State University 
Address:  5500 Campanile Drive, Mechanical Engineering Department 
 
San Diego , CA 92182-0001 
Email: prof.bhattacharjee@gmail.com 
Phone: 619-594-6080  
Congressional District: 53 
Web:  
Organization Type: UNIVERSITY 
Organization Name: San Diego State University 
Comments:  
Co-Investigator(s) / Affiliation:  Miller, Fletcher  Ph.D./ San Diego State University  Paolini, Christopher  Ph.D./ San Diego State University  Takahashi, Shuhei  Ph.D./ Gifu University  Wakai , Kazunori  Ph.D./ Gifu University 
Project Information: Grant/Contract No. NNX15AG11G 
Responsible Center: NASA GRC 
Grant Monitor: Olson, Sandra  
Center Contact: 216-433-2859 
Sandra.Olson@nasa.gov 
Solicitation: 2009 Combustion Science NNH09ZTT001N 
Grant/Contract No.: NNX15AG11G 
Project Type: FLIGHT  
No. of Post Docs:
No. of PhD Candidates:
No. of Master's Candidates:
No. of Bachelor's Candidates:
No. of PhD Degrees:  
No. of Master's Degrees:
No. of Bachelor's Degrees:
Program--Element: COMBUSTION SCIENCE--Combustion science 
Task Description: NOTE: Continuation of "Residence Time Driven Flame Spread Over Solid Fuels," grant # NNX10AE03G.

Flame spread over solid fuels in an opposed-flow environment has been investigated for over four decades for understanding the fundamental nature of hazardous fire spread. The appeal for this configuration stems from the fact that flame spread rate remains steady, even if the flame itself may grow in size. For practical fire safety issues, however, wind-assisted flame spread is more relevant.

However, these two regimes have always been studied in isolation without much effort to establish a connection, even though the underlying mechanism of flame spread is the same in all regimes. Sitting between the two regimes are high-residence time flames, as found in a low-velocity or quiescent microgravity environment. Residence time is the time spent by an oxidizer in the combustion zone. Such flames, which are of interest on their own merit due to fire safety issues in spacecraft, offer some unique characteristics because of the high residence time. Radiation becomes dominant and, based on previous space experiments and analysis, we contend that a vigorously spreading flame on Earth becomes self-extinguishing in a microgravity environment under certain conditions such as the fuel thickness being greater than a critical value.

The proposed research uses a comprehensive approach-- a novel experimental set up and a theoretical framework based on scaling and numerical modeling-- to investigate flame spread driven by varying residence time, from blow-off extinction in an opposed-flow configuration through high residence time flame to blow-off extinction in a concurrent-flow configuration. At the heart of this proposal is a novel but simple experiment where the residence time of the oxidizer can be controlled and high residence time flames can be established for a long duration (compared to drop towers). As a proof of concept, we have constructed a flame tower at San Diego State University (SDSU) in which, after a sample is ignited, the sample holder, placed in an open moveable cart, can be traversed at any desired speed upward or downward, creating an external flow that can augment or mitigate the buoyancy-induced flow. Preliminary results show that we can control the residence time and create flames in different regimes, including a transition between a wind-aided and wind-opposed configuration. At Gifu University in Japan, we have been developing an interferometry based imaging system which we intend to enhance to capture the thermal footprint of a flame's leading edge. The leading edge is central to our understanding of mechanism of flame extinction. Further development of this technology will enable us to integrate diagnostics in future space based experiments and provide validation data to a comprehensive numerical model. The comprehensive model, to be built upon our existing two-dimensional model, will solve an unsteady, three-dimensional, Navier stokes equation with finite rate kinetics in the gas and solid phases and radiation in the gas phase. The software implementation will be object-oriented and utilize a new technology called Web Services that will decouple various sub-models and enhance parallel execution.

The radiation model will also be refined by including the equilibrium composition of species for finding radiative properties in high residence-time flames. The comprehensive model, tested against available theory, data in literature, and data generated at SDSU and Gifu, was applied to test the three hypotheses presented in the preceding grant regarding flame extinguishment in a microgravity environment. A successful outcome of that project is leading to a well thought out space-based experiment on the mechanism of flame extinction in a gravity free environment. We have received authority to proceed to Preliminary Design Review.

 

Research Impact/Earth Benefits: Our research has three components. (a) We have built three experimental setups at SDSU: Flame Tower where a test sample can be traversed up or down at any desired velocity; Flame Stabilizer where the motion of the flame can be arrested by moving the sample exactly at the speed of the flame spread in the opposite direction; and a rotating Flame Tunnel where a combustion tunnel can be oriented at any desired angle to study the interaction of buoyancy and forced flow. (b) Theoretical and computational work that explores the similarity and differences between the mechanisms flame spread in a zero gravity space environment and on Earth; (c) Support the space based experiment (in the SoFIE project) to establish extinction mechanism of flames.

The data that we are acquiring in the experiments provide the research community with a comprehensive set of results for testing different theories of flame spread in a normal gravity environment. Moreover, by controlling the residence time, various regimes of flame spread, including the microgravity regime, can be explored in the Flame Tower. Our theoretical work predicts a fuel thickness beyond which steady flame spread is unsustainable in a gravity free environment. If we are successful in establishing a critical thickness, this will have a powerful impact on making fire resistant environment for humans in space.

 

Task Progress & Bibliography Information FY2016 
Task Progress: Significant progress has been made during this period of the project. The major highlight of this period is analysis of BASS-II experimental results and publication of two archival journal articles based on these results. We also presented several conference papers and have submitted two manuscripts for the 36th International Symposium on Combustion. We have also obtained further ground-based data from our flame tunnel and flame stabilizer setup.

 

Bibliography Type: Description: (Last Updated: 06/13/2019)  Show Cumulative Bibliography Listing
 
Abstracts for Journals and Proceedings Bhattacharjee S, Nadertaber A, McGrath K, Ivisic I. "Opposed-Flow Flame Spread: A Comparison of Microgravity and Normal Gravity Experiments Establishing the Thermal Regime." 8th International Symposium for Physical Sciences in Space and 31st Annual Meeting of the American Society for Gravitational and Space Research, Alexandria, VA, November 11-14, 2015.

31st Annual Meeting of the American Society for Gravitational and Space Research, Alexandria, VA, November 11-14, 2015. , Nov-2015

Abstracts for Journals and Proceedings Simsek A, Bhattacharjee S. "Effect of Boundary Layer on Blow-off Extinction in Opposed-Flow Flame Spread: A Computational Study." 9th So Cal Fluids Symposium, San Diego State University, San Diego, CA, April 18, 2015.

9th So Cal Fluids Symposium, San Diego State University, San Diego, CA, April 18, 2015. , Apr-2015

Articles in Peer-reviewed Journals Bhattacharjee S, Laue M, Carmignani L, Ferkul P, Olson S. "Opposed-flow flame spread: A comparison of microgravity and normal gravity experiments to establish the thermal regime." Fire Safety Journal. 2016 Jan;79:111-8. http://dx.doi.org/10.1016/j.firesaf.2015.11.011 , Jan-2016
Articles in Peer-reviewed Journals Bhattacharjee S, Aslihan S, Olson S, Ferkul P. "The critical flow velocity for radiative extinction in opposed-flow flame spread in a microgravity environment: A comparison of experimental, computational, and theoretical results." Combustion and Flame. 2016 Jan;163:472-7. http://dx.doi.org/10.1016/j.combustflame.2015.10.023 , Feb-2016
Dissertations and Theses Simsek A. (Aslihan Simsek) "Radiative, Thermal, and Kinetic Regimes of Opposed-flow Flame Spread." Masters Thesis, San Diego State University, October 2015. , Oct-2015
Dissertations and Theses Ivisich I. (Ivan Ivisich) "A Validated Radiation Model and Its Application to Microgravity Flame Spread." Masters Thesis, San Diego State University, October 2015. , Oct-2015
Dissertations and Theses Laue M. (Matthew Laue) "Experimental Study of the Effect of Fuel Thickness in Opposed –Flow Flame Spread Over PMMA." Masters Thesis, San Diego State University, April 2015. , Apr-2015
Dissertations and Theses Lotti F. (Francisco Lotti) "Blow-off Extinction in Flame Spread over Thin Fuels: An Experimental Study." Masters Thesis, Univ. of Pisa, Italy, April 2015. , Apr-2015
Papers from Meeting Proceedings Laue M, Ivisich I, Bhattacharjee S. "A Comparison of Radiation Signature from Spreading Flames in Normal and Zero Gravity Environment." 8th Annual Student Research Symposium, San Diego State University, San Diego, CA, March 6-7, 2015.

8th Annual Student Research Symposium, San Diego State University, San Diego, CA, March 6-7, 2015. , Mar-2015

Papers from Meeting Proceedings Bhattacharjee S, Aslihan S, McGrath K, Olson SL, Ferkul PV. "The Critical Flow Velocity for Radiative Extinction in Opposed-Flow Flame Spread in a Microgravity Environment: A Comparison of Experimental, Computational, and Theoretical Results." Presented at 9th Mediterranean Combustion Symposium, Rhodes, Greece, June 7-11, 2015.

Paper LF-16. 9th Mediterranean Combustion Symposium, Rhodes, Greece, June 7-11, 2015. , Jun-2015

Papers from Meeting Proceedings Olson SL, Ferkul PV, Bhattacharjee S, Miller FJ, Fernandez-Pello CF, Link S, T'ien JS. "Results from on-board CSA-CP and CDM Sensor Readings during the Burning and Suppression of Solids – II (BASS-II) Experiment in the Microgravity Science Glovebox (MSG)." 45th International Conference on Environmental Systems (ICES), Bellevue, WA, July 12-16, 2015.

45th International Conference on Environmental Systems (ICES), Bellevue, WA, July 12-16, 2015. ICES paper 2015-196. , Jul-2015

Papers from Meeting Proceedings Bhattacharjee S, Carmignani LI. "The Effect of Boundary Layer on Blow-Off Extinction in Opposed-Flow Flame Spread: Results of Experiments and Simplified Analysis." ATEM'15: International Conference on Advanced Technology in Experimental Mechanics 2015, Toyohashi, Japan, October 4-8, 2015.

ATEM'15: International Conference on Advanced Technology in Experimental Mechanics 2015, Toyohashi, Japan, October 4-8, 2015. , Oct-2015

Papers from Meeting Proceedings Bhattacharjee S, Simsek A, Ivisic I. "The Role of Fuel Thickness in Opposed-Flow Flame Spread in a Quiescent Microgravity Environment." Western States Section (WSS) Technical Meeting of the Combustion Institute, Provo, Utah, October 2015.

Western States Section (WSS) Technical Meeting of the Combustion Institute, Provo, Utah, October 2015. , Oct-2015

Papers from Meeting Proceedings Grayson L, Kievens K, Bhattacharjee S. "Measurement of Thermal Radiation in Stabilized Downward Spreading Flame." Western States Section (WSS) Technical Meeting of the Combustion Institute, Provo, Utah, October 2015., Oct-2015

Western States Section (WSS) Technical Meeting of the Combustion Institute, Provo, Utah, October 2015., Oct-2015 , Oct-2015

Significant Media Coverage Price M. Video by Jeneene Chatowsky. "Fire in the Sky. Article and video about PI's NASA research." SDSU Media Center. 360:The Magazine of San Diego State University, Spring 2015. http://newscenter.sdsu.edu/sdsu_newscenter/news_story.aspx?sid=75511 , May-2015
Project Title:  Residence Time Driven Flame Spread Over Solid Fuels--NNX15AG11G Expand All
Images: icon  Fiscal Year: FY 2015 
Division: Physical Sciences 
Research Discipline/Element:
COMBUSTION SCIENCE--Combustion science 
Start Date: 04/06/2015  
End Date: 04/05/2020  
Task Last Updated: 06/02/2015 
Download report in PDF pdf
Principal Investigator/Affiliation:   Bhattacharjee, Subrata  Ph.D. / San Diego State University 
Address:  5500 Campanile Drive, Mechanical Engineering Department 
 
San Diego , CA 92182-0001 
Email: prof.bhattacharjee@gmail.com 
Phone: 619-594-6080  
Congressional District: 53 
Web:  
Organization Type: UNIVERSITY 
Organization Name: San Diego State University 
Comments:  
Co-Investigator(s) / Affiliation:  Miller, Fletcher  Ph.D./ San Diego State University  Paolini, Christopher  Ph.D./ San Diego State University  Takahashi, Shuhei  Ph.D./ Gifu University  Wakai , Kazunori  Ph.D./ Gifu University 
Project Information: Grant/Contract No. NNX15AG11G 
Responsible Center: NASA GRC 
Grant Monitor: Olson, Sandra  
Center Contact: 216-433-2859 
Sandra.Olson@nasa.gov 
Solicitation: 2009 Combustion Science NNH09ZTT001N 
Grant/Contract No.: NNX15AG11G 
Project Type: FLIGHT  
No. of Post Docs:  
No. of PhD Candidates:  
No. of Master's Candidates:  
No. of Bachelor's Candidates:  
No. of PhD Degrees:  
No. of Master's Degrees:  
No. of Bachelor's Degrees:  
Program--Element: COMBUSTION SCIENCE--Combustion science 
Task Description: NOTE: Continuation of "Residence Time Driven Flame Spread Over Solid Fuels," grant # NNX10AE03G.

Flame spread over solid fuels in an opposed-flow environment has been investigated for over four decades for understanding the fundamental nature of hazardous fire spread. The appeal for this configuration stems from the fact that flame spread rate remains steady, even if the flame itself may grow in size. For practical fire safety issues, however, wind-assisted flame spread is more relevant.

However, these two regimes have always been studied in isolation without much effort to establish a connection, even though the underlying mechanism of flame spread is the same in all regimes. Sitting between the two regimes are high-residence time flames, as found in a low-velocity or quiescent microgravity environment. Residence time is the time spent by an oxidizer in the combustion zone. Such flames, which are of interest on their own merit due to fire safety issues in spacecrafts, offer some unique characteristics because of the high residence time. Radiation becomes dominant and, based on previous space experiments and analysis, we contend that a vigorously spreading flame on Earth becomes self-extinguishing in a microgravity environment under certain conditions such as the fuel thickness being greater than a critical value.

The proposed research uses a comprehensive approach-- a novel experimental set up and a theoretical framework based on scaling and numerical modeling-- to investigate flame spread driven by varying residence time, from blow-off extinction in an opposed-flow configuration through high residence time flame to blow-off extinction in a concurrent-flow configuration. At the heart of this proposal is a novel but simple experiment where the residence time of the oxidizer can be controlled and high residence time flames can be established for a long duration (compared to drop towers). As a proof of concept, we have constructed a flame tower at San Diego State University (SDSU) in which, after a sample is ignited, the sample holder, placed in an open moveable cart, can be traversed at any desired speed upward or downward, creating an external flow that can augment or mitigate the buoyancy-induced flow. Preliminary results show that we can control the residence time and create flames in different regimes, including a transition between a wind-aided and wind-opposed configuration. At Gifu University in Japan, we have been developing an interferometry based imaging system which we intend to enhance to capture the thermal footprint of a flame's leading edge. The leading edge is central to our understanding of mechanism of flame extinction. Further development of this technology will enable us to integrate diagnostics in future space based experiments and provide validation data to a comprehensive numerical model. The comprehensive model, to be built upon our existing two-dimensional model, will solve an unsteady, three-dimensional, Navier stokes equation with finite rate kinetics in the gas and solid phases and radiation in the gas phase. The software implementation will be object-oriented and utilize a new technology called Web Services that will decouple various sub-models and enhance parallel execution.

The radiation model will also be refined by including the equilibrium composition of species for finding radiative properties in high residence-time flames. The comprehensive model, tested against available theory, data in literature, and data generated at SDSU and Gifu, was applied to test the three hypotheses presented in the preceding grant regarding flame extinguishment in a microgravity environment. A successful outcome of that project is leading to a well thought out space-based experiment on the mechanism of flame extinction in a gravity free environment. We have received authority to proceed to Preliminary Design Review.

 

Research Impact/Earth Benefits: Our research has three components: We have built a novel experimental facility called Flame Tower at SDSU, where ground based experiments on flame spread have been conducted; Theoretical and computational work that explores the similarity and differences between the mechanisms flame spread in a zero gravity space environment and on Earth; Design and propose a space based experiment to establish extinction mechanism of flames.

The data that we are acquiring in the Flame Tower will provide the research community with a comprehensive set of results for testing different theories of flame spread in a normal gravity environment. Moreover, by controlling the residence time, various regimes of flame spread, including the microgravity regime, can be explored in the Flame Tower. Our theoretical work predicts a fuel thickness beyond which steady flame spread is unsustainable in a gravity free environment. If we are successful in establishing a critical thickness, this will have a powerful impact on making fire resistant environment for humans in space.

 

Task Progress & Bibliography Information FY2015 
Task Progress: New project for FY2015.

Continuation of "Residence Time Driven Flame Spread Over Solid Fuels," grant NNX10AE03G.

 

Bibliography Type: Description: (Last Updated: 06/13/2019)  Show Cumulative Bibliography Listing
 
 None in FY 2015