燃油分配对超燃冲压发动机的性能影响仿真分析

针对超燃冲压发动机两级燃油分配对内流道流动过程、燃烧模态、发动机性能及调节特性的影响问题,建立了发动机一维流动分析模型；对马赫数6/当量比1,马赫数6/当量比0.6,马赫数4/当量比1三种工况不同的一级/二级燃烧室燃油分配比例下的流动过程进行了仿真,并获得了不同燃油分配规律下的发动机性能.通过分析表明：超燃冲压发动机的两级燃油分配比例直接影响发动机内流道内的流动参数分布、燃烧模态及发动机比冲等性能参数.对于马赫数6/当量比1工况,当一级燃烧室的燃油分配比例为30％～70％时,可在全流道内组织纯超声速燃烧,最高比冲超过800 s；对于马赫数6/当量比0.6工况,即使将所有的燃油均在一级燃烧室喷入,流道也不会壅塞,该工况下最大比冲超过800s；对于马赫数4/当量比1工况,燃烧室内组织亚声速燃烧,最大比冲为1 031.9 s；为保证亚声速燃烧扰动不传递到燃烧室入口外,一级燃油分配比例不应过高.

Simulation and analysis for influence of fuel distribution on scramjet performance

Aiming at the influence of the fuel distribution on the flow mechanism in scramjet duct, combustion mode, engine performance and adjustment characteristic, a one-dimensional scram- jet analysis model was established. Simulation of flow process in one-stage/two-stage fuel distribution percent is carried under three different cases, including Ma 6/ψ, Ma 6/ψ 0.6, Ma 4/ψ 1. Scramjet per- formance in different fuel distribution is obtained. The analysis results show that the flow mechanism, combustion mode and engine performance are strongly dependent on the one-stage/two-stage fuel dis- tribution percent. For the case of Ma 6hp 1, combustion in the duct can be organized in supersonic flow when one-stage combustor fuel distribution is at the range of 30%-70%, whose maximum spe- cific impulse exceeds 800 s. For the case ofMa 6ψ 0.6, combustion is always organized in supersonic