The primary goal of the Flame Design experiment is to improve our understanding of soot inception and control in order to enable the optimization of oxygen enriched combustion and the “design” of non-premixed flames that are both robust and soot free. An outside review panel recently declared that Flame Design “… could lead to greatly improved burner designs that are efficient and less polluting than current designs.” Flame Design will investigate the soot inception and extinction limits of spherical microgravity flames, created in the same manner as for the s-Flame experiment. Tests will be conducted with various concentrations of both the injected fuel (i.e., ethylene or methane) and the oxygen enriched atmosphere in order to determine the role of the flame structure on soot inception. The effect of the flow direction on soot formation will be assessed with an inverse spherical flame unless such testing is not approved by the Payload Safety Review Panel (PSRP). If inverse spherical flame testing is not allowed, the plan is to use a coflow burner, conducting both normal and inverse flame tests. In the case of the inverse flames, the oxygen/inert mixture is injected from a central tube, while the fuel is ejected from a surrounding annulus. The Flame Design experiment will explore whether the stoichiometric mixture fraction can characterize soot and flammability limits for non-premixed flames like the equivalence ratio serves as an indicator of those limits for premixed flames.
Principal Investigaotor: Prof. Richard Axelbaum, Washington University, St. Louis
Co-Investigators: Prof. Peter Sunderland, U. Maryland
Dr. David Urban, NASA GRC
Project Scientist: Dennis Stocker, NASA Glenn Research Center
Deputy Project Scientist: Prof. Fumiaki Takahashi, Case Western Reserve University