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Growth and Extinction Limits: Ground Based Testing of Solid Fuel Combustion in Low Stretch Conditions in Support of Space Flight Experiments

Johnston, Michael C
http://rave.ohiolink.edu/etdc/view?acc_num=case1511915506999995

Abstract Details

2018, Doctor of Philosophy, Case Western Reserve University, EMC - Aerospace Engineering.
This work examines the effect of material preheating on the combustion and flammability of thermally thick poly(methyl methacrylate) (PMMA) solid fuel near the limits of low stretch oxidizer feed rate common in spacecraft. The in depth temperature rises as solid fuel is preheated causing a decrease in conduction away from the solid surface, freeing energy for increased fuel vaporization. A 4 cm diameter PMMA sphere instrumented to measure in depth temperature and conduction was ignited and allowed to burn (preheat) in a low speed wind tunnel in the NASA Zero Gravity Research Facility drop tower. After reaching a specified temperature profile, the tunnel was dropped to cause a step change to microgravity for 5.18 seconds. The flammability boundary is mapped for independent parameters of heat loss to the solid interior and freestream velocity (stretch) near the low speed quenching branch at the near limit conditions of 17% oxygen concentration. Flame standoff distance decreased approximately linearly with increased conduction to the interior. Flame quenching distance decreased with increased freestream velocity (stretch). A second test series at similar stretch rates beneath a 21.8 cm diameter PMMA spherical shell served as a buoyant analog to microgravity tests. Conduction to the interior was held constant throughout each test by controlling the back surface temperature with an ice bath and varying shell thickness between 2.8-12 mm. A well defined surface area in the bottom stagnation zone was exposed to the flame and the remainder masked. Burning samples were suspended from a mass balance to measure global mass loss. Burning rate is expected to be spatially uniform near the stagnation region, therefore the first time derivative of global mass loss divided by exposed area gives local burning rate. Local burning rate as a function of oxygen concentration is presented for various heat losses. This work supports the planned space flight experiment Growth and Extinction Limits (GEL) which is part of the Solid Fuel Ignition and Extinction (SoFIE) project aboard the International Space Station. Significantly longer duration microgravity is made available at the expense of increased experimental complexity. The challenges of chamber confinement and ignition are discussed.
T'ien James, PhD (Committee Chair)
Takahashi Fumiaki, PhD (Committee Member)
Liao Ya-Ting, PhD (Committee Member)
Ishida Hatsuo, PhD (Committee Member)
Olson Sandra, PhD (Committee Member)
Ferkul Paul, PhD (Committee Member)
254 p.
Aerospace Engineering; Mechanical Engineering
Solid Fuel; Combustion; Low Stretch Flames; Microgravity; Flammability; Fire; SoFIE; GEL

Recommended Citations

Citations

  • Johnston, M. C. (2018). Growth and Extinction Limits: Ground Based Testing of Solid Fuel Combustion in Low Stretch Conditions in Support of Space Flight Experiments [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1511915506999995

    APA Style (7th edition)

  • Johnston, Michael. Growth and Extinction Limits: Ground Based Testing of Solid Fuel Combustion in Low Stretch Conditions in Support of Space Flight Experiments. 2018. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1511915506999995.

    MLA Style (8th edition)

  • Johnston, Michael. "Growth and Extinction Limits: Ground Based Testing of Solid Fuel Combustion in Low Stretch Conditions in Support of Space Flight Experiments." Doctoral dissertation, Case Western Reserve University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1511915506999995

    Chicago Manual of Style (17th edition)

case1511915506999995
181
© 2018, some rights reserved.Creative Commons License Growth and Extinction Limits: Ground Based Testing of Solid Fuel Combustion in Low Stretch Conditions in Support of Space Flight Experiments by Michael C Johnston is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.