基于改进温度评估模型的叶片冷却性能分析

为适应航空发动机涡轮冷却技术的发展趋势，在传统叶片温度评估模型的基础上加以改进，提出了适用于内外耦合涡轮叶片的温度评估模型。将改进后的温度评估模型嵌入到发动机整机热力性能计算模型中，对飞机/发动机系统耦合分析，研究了F-16战机在典型飞行任务和飞行包线内高压涡轮导叶的冷却性能。结果表明：在全飞行任务下进行分析时，叶片在实用升限、起飞及大爬升率工况下叶片工作热环境恶劣，叶片易超温；叶片表面温度沿径向为增长趋势，在叶顶处达到最大值。在全飞行包线内进行分析时，叶片表面温度随高度变化明显；包线内高空低马赫数区域叶片的最高温度和承受的热应力最大，叶片最高温度可达1 342 K；高空低马赫数区域的综合冷却效率与包线内的最高冷却效率相比，降低了34.2%，叶片冷却性能下降明显。在进行模型参数敏感性分析时，与基准方案相比，当输入参数改变相同比例，改变冷气进口温度对叶片温度的影响最为显著。

Analysis of blade cooling performance based on improved temperature assessment model

In order to meet the development trend of aero-engine turbine cooling technology, based on the traditional blade temperature evaluation model, an improved model suitable for internal and external coupled turbine blades was proposed. The improved temperature evaluation model was embedded into the engine thermal performance calculation model. And the cooling performance of the high pressure turbine guide vane of F-16 fighter within typical flight missions and flight envelope was studied through the coupling analysis of aircraft and engine. Results showed that: when analyzed on the whole flight mission, under the conditions of practical lift limit, take-off and high climb rate, the blade worked in bad thermal environment and was prone to overheat; the blade surface temperature increased along the radial direction and reached the maximum value at the blade tip. When analyzed in the flight envelope, the blade temperature changed obviously with the height; the maximum temperature and thermal stress of the blade in the high altitude region with low Mach number were the largest, and the maximum temperature of the blade can reach 1342 K; compared with the highest cooling efficiency in flight envelope, the comprehensive cooling efficiency in the high altitude region with low Mach number was reduced obviously by 34.2%. When conducting sensitivity analysis of model parameters, compared with the benchmark scheme, when the input parameters changed by the same proportion, changing the inlet temperature of cool air had the most significant effect on blade temperature.