混合对流绕圆柱涡旋脱落及对传热影响的数值研究

Numerical Study of the Vortex Shedding from a Circular Cylinder and Its Effects on the Heat Transfer of Mixed Convection

利用本文作者改进的关于流函数—涡量方程的数值求解方法 ,模拟了混合对流绕圆柱涡旋脱落及对传热的影响 ,得到了雷诺数 Re与格拉肖夫数 Gr双重作用下圆柱尾迹涡型转变的规律 ,并数值研究了存在小扰动的自由来流、圆柱旋转 (γ)及浮力与来流成不同角度 (δ)等因素对旋涡脱落、对传热的影响。除 Re数外 ,δ,Gr数对尾涡流型及传热产生较大影响 。

By using the numerical method proposed by the author for solving the unsteady equations of stream and vorticity functions, the vortex shedding from a circular cylinder and its effects on the heat transfer of mixed convection are simulated. With the change of both Re numbers and Gr numbers, the laws for the conversion of the wake vortex patterns are obtained. In this paper, the vortex shedding and its effect on the heat transfer are analyzed for some cases, such as those with small fluctuations in the free stream velocity, the rotation (γ) of circular cylinder and the change in the angle (δ) between the directions of the free stream and gravity. Besides the Re numbers, the angle δ and the Gr numbers may have remarkable influence on the wake vortex patterns and the heat transfer, and these parameters can be used for controlling the flows around a circular cylinder and the augmentation of heat transfer. [WT5HZ]