并联式TBCC排气系统模态转换过程的流场特性研究

为了研究并联式TBCC（Turbine Based Combined Cycle）排气系统在模态转换过程中出口流场的变化特性及其气动性能的变化规律，采用动网格等技术完成了某并联式TBCC组合排气系统在整个模态转换过程中的非定常数值模拟。同时，对该排气系统模态转换过程中若干工况时的冷流进行了风洞试验，并将试验与数值仿真结果进行比较。研究结果表明:模态转换过程中，并联式TBCC排气系统出口流场的波系结构十分复杂，分流板出口激波对排气系统的气动性能产生了一定影响；TBCC排气系统的推力系数始终保持在0.9以上，但其产生的升力变化较大；风洞试验获得的壁面压力分布及流场纹影与数值模拟结果吻合较好，从而证明了本文数值模拟方法的可行性。

Study of flow field characteristics of an over-under TBCC exhaust system during mode transition process

To study the flow characteristics and aerodynamic performance of an over-under TBCC exhaust system during the mode transition process, the unsteady numerical simulation of the mode transition process is completed by using dynamic grid method. Moreover, a series of cold flow wind tunnel tests of the TBCC exhaust system are carried out under several working conditions during the mode transition process, and the results are compared with the numerical simulation results. The results show that the wave structure of the TBCC exhaust flow field is extremely complex during the mode transition process, and the shock generated at the trailing edge of the splitter plate has some effects on the aerodynamic performance of the exhaust system. The axial thrust coefficient keeps above 0.9, yet the lift varies greatly during the process. The static pressure distribution on the walls and schlieren images obtained by wind tunnel experiments are consistent well with the numerical simulation results, which proves the accuracy of the numerical simulation results in this paper.