Research of Combustion Dynamics on Cryogenic Flow under Supercritical Pressure

对超临界压力下的低温流动进行了数值和实验研究，以了解其热力学特性和流体动力学。用RANS模拟得到了超临界压力下单轴氮气射流的平均密度分布与实验数据吻合较好。为了捕捉低速H2/O2剪切流剪切层附近的非定常特征，提出了包含多组分质量守恒方程的预调节方法。在LES模拟中，还模拟了理想气体和跨临界条件下的低温氮/氮混合层。结果表明，伪临界温度对湍流涡旋结构的影响较小。在跨临界压力下的低温氮气射流实验中，在拟临界温度附近，沿对称线的温度梯度变小。

The numerical and experimental studies on the cryogenic flow under the supercritical pressure are performed in order to understand the thermodynamic characteristics and fluid dynamics. The averaged density distributions of the mono-axial nitrogen jet flow under the supercritical pressure using RANS simulations agree well with the experimental data. The preconditioning method including multi-species mass-conservation equations was developed to capture the unsteady feature near the shear layer in the low-speed H2/O2 shear flow. As for LES simulations, the cryogenic nitrogen/nitrogen mixing layers in ideal-gas and transcritical conditions were also simulated. The results show that the effects of the pseudo-critical temperature are small on the turbulent eddy structure. In the experiment for the cryogenic nitrogen jet under the transcritical pressure, the temperature gradient along the symmetric line becomes small near the pseudo-critical temperature.