Theoretical Prediction of Critical Pyrolysate Mass Fluxes of a Material to Mitigate Spacecraft or Planetary Habitat Fire
S. M. Dakka (2017), JBIS, 70, pp.12-18Refcode
: Pyrolysate, fuel vapour flow rates, Ignition delay time, planetary environment, PMMA, numerical simulation, Fire preventionAbstract:
Future deep space exploration and plans for planetary settlements prompted researchers to address variety of challenging engineering problems. One problem is developing materials that can mitigate an event of interplanetary spacecraft fire. A numerical simulation of piloted ignition delay time of solid fuel material for PMMA sample, subjected to various incident radiant heat fluxes and airflows was developed based on thermo-chemical solid phase model. The model incorporates, conduction, convection, surface re-radiation and radiation surface absorption heat transfer modes and solid phase chemical degradation described by first order Arrhenius law chemistry. The predicted surface temperature rise adequately captured the measured surface temperatures for forced air flow velocities induced by buoyancy relevant to normal gravity environments. Based on the measured onset temperature of ignition the critical pyrolysate, fuel vapour mass flow rate was deduced in normal gravity conditions. The critical fuel vapour mass flow rate relevant to interplanetary environment was extrapolated based on normal gravity data. The results highlights the urgent need for space policy makers and stake holders to provide more funding directed towards design and fabrication of ground based facilities simulating planetary environments in order to enhance and leverage future planetary habitat designs with capabilities of mitigation on board events of fires.
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