基于带源项非结构网格CE/SE方法的PDRE爆轰排气流场中尾喷管特性研究

Study on Nozzle Performances During Detonation and Exhaust Process of PDRE Based on Unstructured Meshes CE/SE Method With Stiff Source Term

为了研究非定常两相脉冲爆轰发动机爆轰和排气流场中尾喷管的特性,推导了带源项非结构三角形网格求解元守恒元数值方法(CE/SE方法)的计算格式,应用该方法数值研究了满填充工况下带不同结构尾喷管火箭式脉冲爆轰发动机的内外流场和爆轰推进性能。研究表明:该非结构网格CE/SE方法可有效捕捉变截面管中强间断和复杂波系结构。各类喷管中,含收敛段喷管排气时间增长,气流在收敛段喉部发生壅塞;含扩张段喷管内出现斜激波过膨胀现象。当环境压力为0.1 MPa、填充率为1时,单次爆轰模式下带不同类型喷管的汽油/空气两相脉冲爆轰发动机的推进性能:除40°角扩张喷管外,其他各类喷管在爆轰和排气进程中均能提高发动机的冲量。

In order to study the nozzle performances during the unsteady two-phase detonation and exhaust process of pulse detonation rocket engine( PDRE),the calculation formulation of adaptable unstructured meshes space-time conservation element and solution element method( the CE/SE method) with stiff source term was deduced and used to simulate the internal and external flow field of PDRE systems. The study result shows that the CE/SE method is capable of solving flows with strong gradients and complicated wave interaction patterns in variable section tubes. The nozzle with a convergent section exhibits a long blow-down time due to its throat congestion,while the nozzle with a divergent section brings oblique shock waves due to the over-expansion in nozzle. When the ambient pressure and fill rate are 0. 1 MPa and 1 respectively,all nozzles except the divergent nozzle with 40° expansion angle can improve the impulse of gasoline/air PDREs during the detonation and exhaust periods.