V型尾缘喷管流场特性数值模拟

模拟计算了一系列V型尾缘(Chevron)收敛喷管的详细涡结构(包括流向涡和展向涡)、引射系数、推力损失等性能,并与相关实验结果进行了对比验证。采用有限体积QUC IK格式和标准k-ε湍流模型,结合壁面函数求解雷诺平均的N-S方程。通过模拟计算与实验结果的对比,验证了计算方法的可行性。通过计算得出:V型尾缘喷管齿弯角越大,核心区长度越短,喷管出口下游的流向涡和展向涡的强度和尺度也越大。V型尾缘的齿弯角每增加1°,对应的喷管的堵塞比约增加0.98%,喷管的推力损失约增加1.71%,引射系数约增加3.45%。

Numerical simulations on the flow fields downstream chevron nozzles

Several chevron nozzles were numerical simulated.The vortex structure,entrainment ratio and thrust loss were analyzed.The QUICK and finite volume method,standard k-ε turbulence model,wall functions were employed to solve the N-S equations.The result shows that increasing chevron bend angle can enhance the fine-scale mixing,improve the initial axial velocity decay rate and increase the strength and the scale of the streamwise vortices and the slantwise vortices.When the bend angle increases by 1°,the block ratio is improved by 0.98%,the thrust loss is raised by 1.71% and the thrustper-mass-flux is improved by 3.45%.