丁胞型强化换热管的数值模拟

NUMERICAL SIMULATION OF DIMLED TUBES FOR HEAT TRANSFER ENHANCEMENT

在换热器管道的内壁面上布置丁胞可以有效地增强管道内的传热。通过三维数值模拟,对含丁胞的圆形截面管道内的定常不可压缩湍流流动进行了数值模拟。本文采用RNGκ-ε方程模型作为湍流计算模型和SIMPLE算法求解管道的流动传热情况。数值模拟结果表明,丁胞的大小、深度、排列密度等几何结构均对管道的换热效果有一定影响.在较低雷诺数下,含较小丁胞的管道换热效果好于含较大丁胞的管道;在较高雷诺数下,含较大丁胞的管道换热效果好于含较小丁胞的管道。

Heat transfer enhancement was investigated in a coaxial-pipe heat exchanger using dimples on the inner tube. Through three-dimensional numerical simulation, the incompressible fluid flow and heat transfer characteristics in the dimpled tube were studied. This computational model is built up by RNG κ-ε turbulent govern equation and SIMPLE algorithm. By this study, the thesis shows that the geometry structures such as the size, depth and the distributed density of dimples affect heat exchange performance of dimpled tubes. When Reynolds number is low, the heat exchange efficiency of tubes with smaller dimple is higher. When Reynolds number is high, the heat exchange efficiency of tubes with bigger dimple is higher.