限流方法解耦燃烧与喷射过程的合理性研究

Rationality Study of Flow Chock for Decoupling Combustion and Injection Process

关键词:  超燃冲压发动机  限流  燃烧工况模拟  燃料射流发展  实验与数值分析

Key words:  Scramjet  Flow chocking  Combustion case simulation  Fuel injection process  Experiment and numerical simulation

摘要:

为了研究双模态超燃冲压发动机燃烧室在燃烧诱导的高背压环境下燃料的输运和分布情况，采用了限流方法模拟燃烧诱导的高背压环境。针对燃烧室中凹槽上游氢气燃料喷射工况的研究发现，限流试验的压力分布与燃烧试验压力分布在燃烧室前半段比较接近，证明二者的流场在燃料喷射段有一定的相似程度；数值模拟结果表明，相较于低背压状态下62%的混合效率，高背压状态下混合效率提高到了87%，并且燃烧状态下拍摄的火焰区域与限流状态下数值模拟的燃料的可燃质量分数范围相符，证明了限流方法解耦燃烧与喷射过程的合理性。

Abstract:

In order to investigate fuel transportation and distribution in high backpressure dual-mode scramjet combustor environment，mechanical blockage methods was used to simulate high backpressure induced by combustion condition. It is found that in the upstream part of the combustor the pressure distribution in chocking case is consistent with combustion case when hydrogen fuel is injected upstream of cavity，this proved that the flow field in both cases have a certain degree of similarity. Numerical simulation results indicate that mixing efficiency increased to 87% in high backpressure condition，while that in low backpressure condition is 62%. In addition，the flame zone in combustion case which was shot by camera is consistent with combustible mass fraction contour line obtained by numerical simulation，this proved the rationality of flow chocking for decouple combustion environment and injection process.