串联式TBCC发动机风车冲压模态性能模拟

建立了基于部件低转速特性匹配的串联式涡轮基组合循环（TBCC）发动机风车冲压模态性能计算模型，提出了压气机低转速大流量特性扩展方法，由换算扭矩代替等熵效率表示旋转部件特性，解决了低转速部件效率不连续相关问题。分析了冲压外涵面积变化和涡轮功率提取对风车冲压模态性能及部件匹配的影响规律，并基于推力、流量连续准则设计了涡轮模态至冲压模态转换过程（含风车冲压模态）的参数调节规律。计算结果表明:在风车冲压模态下，冲压外涵面积变化对风扇工作状态有显著影响，对压气机影响较小；涡轮可提取功率随着风车转速的减小先增加后降低，比冲随提取功率的增加基本呈线性降低趋势，功率提取位置（高、低压涡轮）对部件匹配有显著影响。 

Simulation of windmilling-ram mode performance for tandem TBCC engine

The windmilling-ram mode performance simulation model was developed for a tandem turbine-based combined cycle (TBCC) engine based on the matching of the component low-speed characteristics. Extrapolation method for the compressor characteristics at low-speed and high flow region was proposed, and the issues associated with the component efficiency discontinuity at low speeds were solved through substitution of isentropic efficiency by corrected torque while describing the characteristics map of rotational component. Influence of ram bypass area variation and turbine power offtake on the windmilling-ram mode performance and component matching was analyzed, and parameter regulating laws during mode transition, including the windmilling-ram mode, were investigated based on the smooth variation of engine thrust and airflow. The simulation results showed that: under the windmilling-ram mode, the fan operation was strongly related to the ram bypass area variation, exerting a relatively small influence on the compressor operation; with the increase of the windmilling spool speed, turbine power offtake first rose and then dropped, and the specific impulse was linearly reduced with the increase of turbine power offtake, while the power offtake location of high-pressure or low-pressure turbine had a significant influence on the component matching.