论文部分内容阅读
凹腔是一种常用的超燃冲压发动机火焰稳定装置,在超燃冲压发动机的设计过程中准确了解凹腔在不同飞行速度下的性能表现是十分重要的,由于凹腔内流体运动非常复杂掌握凹腔结构参数对凹腔内流场结构的影响是比较困难的。采用数值模拟对超声速凹腔流场结构进行了分析,着重研究了来流马赫数和凹腔长深比对凹腔剪切层增长特性的影响。研究表明,马赫数和凹腔长深比增大均导致凹腔剪切层增长率下降;马赫数对凹腔剪切层的影响和其对自由剪切层的影响类似,而长深比对凹腔剪切层的影响近似呈线性变化,且涡量厚度和可视厚度具有相似的变化特点;剪切层中心线的也同时受来流马赫数及凹腔长深比的影响。基于参数化计算结果,并借鉴自由剪切层增长率的建模思路和方法,成功建立了一个考虑了马赫数和长深比影响的超声速凹腔剪切层增长率预测模型,并用数值仿真的结果进行了模型的精确度验证。
Cavity is a commonly used flame stabilization device of scramjet. It is very important to know exactly the performance of cavities at different flight velocities during the design process of scramjet. Because of the complicated fluid movement in the cavities, The influence of cavity structure parameters on the flow field structure in the cavity is more difficult. The numerical simulation was used to analyze the flow field in the supersonic cavity. The effects of Mach Mach number and cavity depth-depth ratio on the growth characteristics of the cavity shear layer were studied emphatically. The results show that the Mach number and the ratio of cavity depth to depth both lead to the decrease of the growth rate of the cavity shear layer. The influence of the Mach number on the cavity shear layer is similar to that of the free shear layer, The influence of the cavity shear layer changes approximately linearly, and the vorticity thickness and visual thickness have similar variation characteristics. The centerline of the shear layer is also affected by Mach-number and depth-to-depth ratio of the cavity. Based on the parametric calculation results and the modeling ideas and methods of free shear layer growth rate, a prediction model of growth rate of supersonic cavity shear layer considering Mach and deep-depth ratio was successfully established. Results The accuracy of the model was verified.