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为获得受限空间内激波作用下的超声速混合层生长规律,以支板喷射超燃冲压发动机典型流道为研究对象,开展了2.3Ma氢气射流与2.0Ma空气来流所形成的超声速混合层的生长特性研究.基于OpenFOAM计算平台,采用大涡模拟方法,数值研究了超声速混合层的流场结构和特征,流场结构和组分分布与实验结果吻合较好.通过超声速混合层组分浓度、厚度、可压缩效应及总压损失的分析,获得了超声速混合层的生长特性.研究结果表明:受限空间内超声速混合层的生长过程具有4个典型阶段,支板末端的膨胀波/激波结构会显著减低对流马赫数,从而降低混合层的可压缩性,促进混合层的生长;激波与混合层的相互作用能够增强局部湍流强度,获得涡量增益,加快混合层的生长速率,促进混合效率,但同时会引起较大的总压损失,降低发动机性能.发动机设计时要综合考虑波系结构与混合层相互作用带来的混合增强和总压损失,实现性能优化.
In order to obtain the growth law of supersonic mixed layer under shock wave in confined space, taking the typical runner of scramjet scramjet as the research object, the supersonic mixing layer formed by 2.3Ma hydrogen jet and 2.0Ma air jet was developed. Based on the OpenFOAM calculation platform, the structure and characteristics of the flow field in the supersonic mixing layer are numerically studied by using the large eddy simulation method.The structure and composition distribution of the flow field agree well with the experimental results.According to the results of supersonic mixing layer component concentration , Thickness, compressibility and total pressure loss, the growth characteristics of the supersonic mixed layer were obtained.The results show that the growth process of the supersonic mixed layer in the confined space has four typical stages, the expansion wave / excitement The wave structure can significantly reduce the convective Mach number, thereby reducing the compressibility of the mixed layer and promoting the growth of the mixed layer. The interaction between the shock layer and the mixed layer can enhance the local turbulence intensity, obtain the vorticity gain, accelerate the growth rate of the mixed layer, Promote the mixing efficiency, but at the same time will cause a greater total pressure loss, reduce engine performance. Engine design should take into account the wave structure and mixing Layer-to-layer interactions increase mixing and total pressure loss for optimal performance.