涡轮叶片流动换热的特性研究

发布时间：2018-11-13 12:00

【摘要】：航空发动机作为飞机的“心脏”,对飞机性能的提升起着决定性作用,而发动机性能的提升很大程度上依赖于涡轮前总温的提高。近年来,燃烧室出口的温度逐年增加,致使涡轮叶片的工作环境变得越来越恶劣,叶片的工作温度也已远远高于材料允许的耐热温度。因此,必须采取有效的冷却方式对涡轮叶片进行冷却保护,这样才能确保发动机工作的可靠性,延长发动机的寿命。涡轮一级导向叶片直接面对来自燃烧室燃气的热冲击,其前缘和缘板区域的流动和传热均异常复杂,且此区域更加易于被高温燃气所烧蚀,因此本文对某一特定涡轮导向叶片的前缘区域和缘板区域的流动换热特性分别进行了研究,主要内容为:叶片前缘流动换热特性研究,建立了12个不同叶片前缘结构的模型,通过数值计算的方法,分别研究了次流雷诺数、吹风比及气膜孔形状对气膜孔流量系数和叶片表面平均绝热冷却效率的影响,研究结果表明,(1)在相同形状气膜孔下,气膜孔的流量系数随着次流雷诺数的增加而增加,在低次流雷诺数下,流量系数增幅明显。(2)在相同次流雷诺数下,复合形状气膜孔的流量系数要比圆柱形孔的大。(3)对于吸力面有气膜孔排的模型,叶片表面的平均绝热冷却效率随着吹风比的增加先增加后减小,在气膜再附壁区域,平均绝热冷却效率又有所增加;对于压力面有气膜孔排的模型,靠近气膜孔出口附近的绝热冷却效率随着吹风比的增加而减小,且平均绝热冷却效率沿叶片型面逐渐降低。涡轮叶片缘板的流动换热特性研究,通过建立几种不同缘板间隙模型,运用Fluent软件进行数值计算,研究不同缘板间隙下缘板的温度分布。研究表明,随着缘板间隙变大,缘板的高温值逐渐提前且高温区域逐渐扩大。
[Abstract]:As the "heart" of aircraft, aero-engine plays a decisive role in improving the performance of aircraft, and the improvement of engine performance depends largely on the increase of total temperature in front of turbine. In recent years, the temperature at the outlet of combustion chamber increases year by year, which makes the working environment of turbine blade worse and worse, and the working temperature of turbine blade is much higher than the heat-resistant temperature allowed by the material. Therefore, an effective cooling method must be adopted to protect the turbine blade in order to ensure the reliability of the engine and prolong the engine life. The flow and heat transfer of the leading edge and the edge plate of the turbine are very complicated when it directly faces the heat shock from the combustion chamber gas, and this region is more easily ablated by the high temperature gas. Therefore, the flow heat transfer characteristics of the leading edge region and the edge plate region of a particular turbine guide blade are studied in this paper. The main contents are as follows: the flow heat transfer characteristics of the leading edge of the blade are studied, and 12 models of the leading edge structure of the blade are established. The effects of the secondary Reynolds number, the blowing ratio and the shape of the film hole on the flow coefficient of the film hole and the average adiabatic cooling efficiency of the blade surface are studied by numerical calculation. The results show that: (1) under the same shape of the film hole, The flow coefficient of the film hole increases with the increase of the secondary Reynolds number, and the increase of the flow coefficient is obvious at the low secondary Reynolds number. (2) at the same secondary Reynolds number, The flow coefficient of the composite film hole is larger than that of the cylindrical hole. (3) for the model with a suction surface with a film hole, the average adiabatic cooling efficiency of the blade surface increases first and then decreases with the increase of the blowing ratio, and then decreases in the region of the film attached to the wall. The average adiabatic cooling efficiency is increased. The adiabatic cooling efficiency near the outlet of the gas film hole decreases with the increase of the blowing ratio, and the average adiabatic cooling efficiency decreases gradually along the blade surface. In this paper, the flow heat transfer characteristics of turbine blade edge plate are studied. By establishing several different edge plate gap models and using Fluent software, the temperature distribution of the edge plate under different edge plate clearance is studied. The results show that the high temperature values of the edge plates advance and the high temperature regions expand gradually with the gap between the edge plates becoming larger.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V231.1

【相似文献】