中轴流场参数波动对超燃燃烧室性能的影响研究

Influence of Axial Flow Field Parameter Fluctuations on Performance of Scramjet Combustor

当吸气式飞行器在进行宽域飞行时,燃烧室中轴线上流场会发生较大改变,流场参数沿轴向发生“波动”。因此,有必要开展中轴线流场参数波动对燃烧室性能的影响研究,为吸气式飞行器燃烧室在进行宽域飞行设计时提供相关理论支持。在N-S气相控制模型的基础上,结合燃烧模型、湍流模型、燃速模型、加质模型,建立了固体燃料超燃冲压发动机燃烧室流动燃烧数值仿真模型。通过该模型,开展中轴线上流场参数波动对燃烧室性能的影响。研究结果表明:宽域飞行时不同的飞行工况导致的入口空气流量不同,会引起燃烧室内马赫数沿流向振荡,振荡幅值越大,总压损失越大。入口空气流量过高或过低都会导致燃烧室内气流马赫数振荡,但选取合适的入口流量可显著降低燃烧室气流马赫数的振荡幅值。因此,针对需要在宽域条件下工作的燃烧室,应设计合适的入口流量使燃烧室整个工作周期内流场马赫数振荡综合最小,进而降低燃烧室流动损失,并提升燃烧室工作性能。

When air-breathing aircraft is flying over a wide area,the upflow of the combustor central axis will change greatly,and the flow field parameters will fluctuate along the axis.Therefore,it is necessary to carry out a study on the influence of axis flow field parameter fluctuation on combustion chamber performance,so as to provide relevant theoretical support for the combustion chamber of air-breathing aircraft in wide-area flight design.Based on the N-S gas-phase control model,combined with combustion model,turbulence model,burning rate model and mass transfer model,a numerical simulation model of flow combustion in solid fuel scramjet combustor is established.Through this model,the influence of the upflow field parameter fluctuation of the central axis on the combustor performance is carried out.The results show that for a optimized combustor configuration,different inlet air flow rates will cause the Mach number of the combustor to oscillate along the flow direction.The greater the oscillation amplitude,the greater the total pressure loss.Too high or too low inlet air flow rate will both result in Mach number oscillation in the combustor.However,selecting a suitable inlet air flow rate can significantly reduce the Mach number oscillation of combustor flow.Therefore,for different combustor configurations,appropriate inlet air flow should be designed to reduce the Mach number oscillation of the flow field in the combustor,reducing the flow loss and improving the working performance of the combustor.