楔形仿螺旋肋片内冷通道的流动与换热

Numerical prediction of turbulent flow and heat transfer in helix-alike internal cooling passage with wedged-fins

利用有限体积法对三维不可压缩的N-S方程进行离散,对上下表面带有错排间断性楔形肋片且对置的仿螺旋内冷通道进行了数值模拟。网格划分采用非结构化混合网格,湍流模型为kε-两方程模型,在近壁面处采用标准壁面函数法进行处理,速度和压力的耦合采用S IM PLE算法。计算获得了楔形仿螺旋肋片内冷通道在楔形肋片与主流方向夹角分别为0°、15°、30°时的三维流场分布。结果表明楔形仿螺旋肋片内冷通道的流场结构比较复杂,通道内流体流动达到了预期的仿螺旋流动效果。通道的平均努谢尔数随楔形肋片与主流夹角的增大而呈增大趋势,通道换热强度得到了明显的提高,但同时流动阻力也显著增加。

The turbulent flow and heat transfer in helix-alike internal cooling passage of the gas turbine blades were predicted by numerical simulation, in which the staggered arrays of discrete helix-alike wedged-fins with a certain angle were used along two inside opposite walls. The finite volume method with unstructured meshes was used to solve the 3-D Navier-Stokes equations. The conventional κ-ε turbulence model was employed together with standard wall function for near the wall treatment. The velocity and pressure was coupled using the SIMPLE algorithm. The anticipative complex 3-D accelerated spiral-flow field of helix-alike internal cooling ducts was presented with helix-alike wedged-fin angles 0°,15°,30°respectively. Results indicate that the averaged Nusselt number ratios （Nu/Nuo） increase with increasing helix-alike wedged-fin angles for all the cases studied. The heat transfer is enhanced remarkably but the pressure loss also increased.