【摘要】 对倾斜同心套管夹层内的自然对流换热进行了数值模拟 .采用面扫描结合三维块修正的技术 ,并在压力和速度修正方程中运用了预测和校正技术 ,使得程序的收敛性、收敛速度和计算精度大为提高 .数值模拟结果表明 :同心套管在水平放置且高宽比 H较小时受端面效应影响换热要低于二维模型得到的值 ,在 H>1 0情况下可以用二维模型来近似 ;在倾斜放置时 ,决定换热的因素除Ra之外 ,半径比、H、倾角等均有影响 ;换热 Nu随 Ra和半径比的增大而上升 ;此外存在一临界高宽比 ,其值约在 3～ 5,与半径比有关 ;当 H小于临界值时 ,Nu随倾角的增大而上升 ,反之则下降更多还原

【Abstract】 Numerical study was carried out to investigate the natural convection heat transfer in concentric annuli under inclined condition. Surface scanning with 3 D block correction technique as well as prediction and correction method in the pressure and velocity correction were used to promote the convergency, the rate and accuracy of convergence. The parameter range of this paper is: Ra * number 10 2～10 6, radius ratio 1.33~10, aspect ratio 1~25, inclined angle 0~90°. Under horizontal position with low aspect ratio, the Nu number is lower than that of 2 D model due to the end plate effect. It is reasonable to use 2 D heat transfer result to calculate if the aspect ratio is larger than 10. When the annuli is in inclined position Nu number is determined by radius ratio, aspect ratio, inclined angle as well as Ra number and Pr number. Nu number is increased with the Ra number and radius ratio monotonously. Critical aspect ratio of value between 3~5 is found which is affected by radius ratio. When aspect ratio is less than the critical aspect ratio, Nu number increases with inclined angle, otherwise Nu number decreased with inclined angle.更多还原