Effect of geometry parameters on the hydrocarbon fuel flow rate distribution in pyrolysis zone of SCRamjet cooling channels

摘要

Hypersonic air-breathing propulsion (Mach 5) based on SCRamjet promotes the revolutions of both military and civilian applications. However, the engine thermal protection is seriously challenged due to high Mach number. One of the key problems is mal-distribution of hydrocarbon fuel in regenerative cooling channels under the complex thermal boundaries and channel geometry, which may cause structural failure. To improve the cooling channel design and achieve better fuel flow distribution, the effect of channel geometry parameters on flow distribution in pyrolysis zone is numerically studied. Both geometry induced and heat flux induced flow mal-distribution are concerned. The study indicates that the flow and heat transfer features in pyrolysis zone of parallel channels differs with those in non-pyrolysis zone. The flow distribution deviations in pyrolysis zone are lower. When the channel aspect ratio varies, thermal stratification dominates flow distribution more than the variation of heat flux on heated surface in pyrolysis zone, which is opposite of that in non-pyrolysis zone. Besides, thinner rib and smaller total flow area achieve better cooling performance while consuming less fuel chemical heat sink. The results help to conclude possible references to the design of cooling channels with fuel pyrolysis considered. (C) 2019 Elsevier Ltd. All rights reserved.