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采用数值方法研究了狭缝射流冲击柱状凸形表面的流动换热特性,通过四种湍流模型计算结果与实验数据对比,确定了湍流模型适用性.以压力梯度分布为依据,重点分析了狭缝射流沿柱状凸形表面的流动结构和边界层分离特点及柱状凸形表面的强化换热特性.结果表明:RNG k--ε和Realizable k--ε模型具有预测适应性;狭缝射流冲击至柱状凸形表面,气体沿表面运动,速度降低,并在流动下游发生边界层分离;量纲一的逆压梯度随量纲一的曲率半径(D/B)的减小而增大,使得边界层分离更早出现;驻点区域换热Nu随量纲一的曲率半径(D/B)的减小而获得增强,但流动进入下游后,D/B对换热基本无影响;压力梯度是影响狭缝射流冲击柱状凸形表面换热分布的重要因素.
The numerical simulation of flow and heat transfer characteristics of a cylindrical jet with a slit jet impacting on a cylindrical convex surface is presented. The results of the four turbulence models are compared with the experimental data to determine the applicability of the turbulence model. Based on the pressure gradient distribution, Jet flow along the cylindrical convex surface and the separation of the boundary layer and the enhanced heat transfer characteristics of the cylindrical convex surface.The results show that the RNG k - ε and Realizable k - ε models have predictive adaptability, Columnar convex surface, the gas moves along the surface, the velocity decreases, and the boundary layer separates downstream of the flow. The magnitude of the pressure gradient increases with the decrease of the radius of curvature (D / B) of dimension one, so that the boundary Layer separation occurred earlier; the heat transfer Nu in stagnation area was enhanced with the decrease of the radius of curvature (D / B) of dimension one, but D / B had little effect on the heat transfer after flowing into the downstream; the pressure gradient was An Important Factor that Affects the Distribution of Heat Transfer in a Cylindrical Convex Surface Caused by a Slit Jet.