结构参数对圆转矩形喷管换热的影响

Effects of structure parameters on heat transfer in round to rectangular nozzles

为了解结构参数对圆转矩形内喷管再生冷却换热的影响,设计了多个圆转矩形喷管,考虑了三种结构参数:转方位置、出口高宽比和出口圆角大小的影响。采用有限体积法求解三维可压缩的N-S方程对其内部流动和换热进行了数值模拟。湍流模型采用标准的k-ε双方程模型,壁面附近的流动和传热采用壁面函数法处理,速度与压力的耦合采用SIMPLE算法求解。结果表明:在型面一阶导数连续的情况下,转方位置对圆转矩形内喷管的换热影响不大;出口高宽比对圆转矩形内喷管的换热影响较大,出口高宽比不能太小,否则影响内喷管流场和换热;出口圆角大小影响内喷管周向上的温度分布,圆角太小造成周向温度分布不均匀。

To understand influence of structure parameters on heat transfer in round to rectangular nozzle（ R R nozzle） , several RR nozzles were designed. Three parameters were taken into consideration： round to rectangular transforming position, ratio of height to width and arc radius at exit. Three dimensional Navier-Stokes equations were solved with finite volume method. Standard k-ε turbulent model and wall function were used for near wall treatment. The coupling of pressure and velocity were realized with SIMPLE algorithm. Results indicate： under conditions that contour derivative is consecutive, transforming position does not significantly affect heat transfer in RR nozzles; height to width ratio at exit greatly influences heat transfer in RR nozzles and too small ratio would lead to high temperature points on gas side wall; arc radius has an effect on surface temperature of perimeter of gas side wall and too small radius makes circumferential temperature non-uniform.