带有倾斜楔形肋片矩形通道内的流动与换热

Turbulent flow and heat transfer in rectangular passage with tilted wedged-fins

提出了一种新型的燃气轮机叶片内部通道强制对流冷却方案．为了探明该种对置叉排倾斜楔形仿螺旋肋片通道结构特有的综合挟热效果，利用数值分析方法研究了在通道宽高比为2．9、肋高与通道当量直径比为0．336、肋片与轴面的夹角为15°、雷诺数在2×10^4～1×10^5的非旋转情况下，雷诺数、肋片与主流方向夹角等参数对通道强化传热和流动阻力特性的影响．研究结果表明，该仿螺旋通道内流体流动达到了预期的仿螺旋流动效果，且该仿螺旋流动的效果随着楔形肋片与主流方向的夹角的增大而效果愈趋明显。这种旋转流动特性对内冷通道的强化传热和流阻特性具有很强的影响，与光滑通道相比，通道平均努塞尔数得到了明显的提高，但同时流动阻力也显著增加．

The numerical investigation was performed to predict three-dimensional turbulent flow and heat transfer in a newly proposed scheme of internal cooling passage of the gas turbine blades, in which the staggered arrays of discrete helix-alike wedged-fins with a certain angle were used along two inside opposite walls. The detailed discussion of the influences of some parameters on the heat transfer and pressure drop in the stationary rectangular passage, such as Reynolds number and the angle between the helix-alike wedged-fins and the main flow direction （α）, is presented for cross-section aspect ratio of 2.9, fin height to hydraulic diameter ratio of 0. 336, the inclined angle of the helix-alike wedged-fins of 15° and Reynolds number in the range of 2 ×10^4 to 1× 10^5. A complicated 3-D accelerated spiral-flow which is just like the fluid flow in helical-fin tube has been formed and the spiral-flow fashion becomes more remarkable with the increasing of angle a. This feature of the spiral-flow has significant effects on the heat transfer enhancement and flow resistance. Compared with fully developed turbulent flow in a smooth circular tube, the averaged Nusselt number markedly increases in this rectangular passage for the all studied cases. Meanwhile the pressure loss also has remarkable increase.