为了提高发动机高温涡轮叶片的冷却效率,延长使用时间,通过增强换热技术,采用数值仿真计算方法,在Realizable k-ε湍流模型上对球形凸包壁面的光滑矩形通道进行了换热特性研究,分析了凸包区域流场特性以及导致凸包区域换热增强的机理.在Re=20000 ～60000的范围内比较了三种不同凸包深度的换热性能,研究了凸包深度对换热和流阻的影响,计算结果表明随着凸包深度增加,换热增强因子和流阻增大因子增加,平均综合换热性能也有所增强.计算数据显示Re数对凸包壁面的换热增强因子和阻力增大因子的影响相对较小,对平均综合传热性能的影响也相对较小.仿真结果验证-了仿真模型可为增强换热性能设计提供依据.%In order to improve the cooling efficiency of high-temperature turbine blades of the engine and extend the working hours, the paper used numerical simulation method and Realizable k-e turbulent model to gain the characteristics of heat transfer on the smooth wall in a rectangle channel, which had spheric convexities on the opposite wall. It analyzed the fluid characteristics of the convex region and the reason to enhance the heat transfer. Relative clearances (5/d) between the convexities and the smooth wall of 0.1, 0. 15, and 0.2 were investigated in a Reynolds number ranging from 20000 to 60000. The results show that the Nusselt number ratios and the friction factor ratios increased as the convex depth increased, and globally-averaged Nusselt numbers also increased. Data also illustrate that the influences of Reynolds number on Nusselt number ratio and friction factor ratio, and globally-averaged thermal performance, are relatively small. Simulation results validate the feasibility and rationality.
展开▼
