Miniaturized Combustor for Supersonic Methane-Air Flames

摘要

A miniaturized combustor has been designed that can produce open supersonic methane-air flames amenable to laser diagnostics. The combustor is based on a two-stage design. The first stage is a vitiation burner that provides ignition and flameholding. The design of the vitiation burner was inspired by well-known principles of jet engine combustors. The salient parameters of operation were explored experimentally, and flameholding was verified computationally using a well-stirred reactor model. Both experiments and computations were used to verify a traditional scaling used in jet engine combustor design. The second stage of the combustor generated an external supersonic flame, operating in premixed and partially premixed modes. The equivalence ratio of the external supersonic flame was varied, as well as the total mass flow rate, and the overall flame phenomenology was examined, specifically supersonic flame length. The very high Reynolds numbers and strain rates present in the supersonic flames should provide a useful testbed for the examination of flame suppression and extinction using laser diagnostics.