具有发散冷却功能的曲面结构边界层特性实验和数值研究

Experimental and numerical investigations of boundary layer performances on curve structure surfaces with transpiration cooling function

用实验测量和理论计算相结合的方法,研究了具有发散冷却功能的曲面结构边界层流动和换热特性.半球形实验件由高温合金钢粉末烧结的多孔材料制成,孔隙率和特征尺寸分别为0.37和20μm.实验件外部的热流温度及速度由热风洞的控制系统给定,内部的冷气流量由数字式质量流量控制器给定,外表面温度由NEC TH5104远红外热像系统测量.利用FLUENT软件中的二维、稳态、局部热平衡模型,对实验件进行发散冷却特性数值模拟,并通过与实验数据的比较,验证数学模型和数值方法.

With the combined approach of experimental investigation and numerical simulation,the fluid flow and heat transfer performances within the boundary layers of a curve structure with transpiration cooling function were studied. The specimen used in the experiments was made of sintered refractory steel, which has a porosity of 0.37 and a character length of 20μm. The temperature and velocity of free stream were controlled by two control systems of a hot gas wind tunnel, and the Reynolds number of gaseous coolant was given by a digital mass flow rate controller. The surface temperature on the specimen was measured by an infrared thermal imaging system,NEC TH5104. Using a two-dimensional,steady and local thermal equilibrium model of the commercial software FLUENT 6.3, the transpiration cooling performance of the specimen was numerically simulated under the same conditions with the experiments. Through comparison of the numerical results with the experimental data,the numerical program was validated. With the help of the validated program,the fluid flow and heat transfer performances within the boundary layer of the curve structure were discussed.