论文部分内容阅读
燃烧加热风洞中的地面高超声速试验通常模拟真实飞行状态下的静温,静压,马赫数(TPM)或总焓,动压,马赫数(h0QM)。为弄清气流参数匹配方式对发动机性能的影响及其机理,基于准一维带化学反应数值模拟对这两种典型匹配方案获得可靠的燃烧室压力分布与发动机推力及比冲的能力进行了比较。结果表明,对于氢燃料加热气流,若燃烧室内未出现明显的局部热壅塞引起的激波结构,TPM匹配方案能较好模拟纯空气流动当量比相同时的压力分布;h0QM匹配方案则能更好模拟燃料量相同的情况;对于模拟燃烧室热壅塞效应,h0QM匹配方案表现更好。从模拟发动机推力的角度来说,两种匹配方案均可通过调整燃油量达到与纯空气结果的较好契合,不管燃烧室内是否出现壅塞激波结构;从模拟燃料比冲的角度来说,则h0QM匹配方案更可靠。燃烧释热比不同是导致两种匹配方案表现不同的关键原因。对于酒精燃料加热气流,两种匹配方案下发动机性能相仿;但此时污染效应更强,给优化匹配方案以准确模拟发动机性能带来更多挑战。
Surface hypersonic tests in combustion heated wind tunnels typically simulate static temperature, static pressure, Mach number (TPM) or total enthalpy, dynamic pressure, Mach number (h0QM) under real-world flight conditions. In order to understand the influence of air flow parameter matching on engine performance and its mechanism, the reliable combustion pressure distribution and engine thrust and specific impulse capacity were compared based on the quasi-one-dimensional chemical reaction numerical simulation . The results show that for the heating flow of hydrogen fuel, the TPM matching scheme can better simulate the pressure distribution when the flow equivalence ratio of pure air is the same, if there is no obvious shock wave structure caused by local thermal congestion in the combustion chamber. The h0QM matching scheme is better Simulating the same amount of fuel; h0QM matching scheme performed better for the thermal plug effect of the simulated combustion chamber. From the perspective of simulating the thrust of the engine, both of the matching schemes can achieve a better fit with the pure air result by adjusting the amount of fuel, regardless of whether a choke shock structure is present in the combustion chamber or not; from the point of view of simulated fuel ratio impulse h0QM matching scheme is more reliable. The difference in combustion heat release ratio is the key reason for the different performance of the two match options. For the heated flow of alcohol fuel, the engine performance is similar for both match scenarios; however, the pollution effect is stronger at this time, presenting more challenges for optimizing the match plan to accurately simulate engine performance.