【摘要】 通过求解三维稳态不可压缩N-S方程和能量方程,对半封闭层流方管冲击射流的流动与传热特性进行了数值研究。根据计算结果分析了射流中四个偏心速度峰值形成的原因,在层流范围内考察了射流雷诺数和冲击高度对流场结构和传热性能的影响。计算结果表明,冲击射流的传热特性受流场结构的控制,冲击面附近水平断面上四个偏心速度峰值的形成,导致在相应断面上形成温度分布的四个偏心最小值,以及在冲击面上形成局部Nu数的四个偏心峰值。更多还原

【Abstract】 The flow and heat transfer characteristics of a semi-confined laminar impinging square jet are investigated numerically by using the solution of the steady-state three-dimensional Navier-Stokes and energy equations for incompressible flows. Numerical results are presented to analyze the mechanism of the formation of the four streamwise velocity off-center peaks in jet. The effects of inlet Reynolds number and plate-to-plate spacing on jet flow-field structure and heat transfer characteristics are examined in the laminar range. The calculated results show that heat transfer performance of the impinging jet is dominated by the flow structure. It is the for- mation of the four off-center velocity peaks at the horizontal cut planes near to the impingement surface that results in the formation of the four temperature off-center minima at the corresponding cut planes and the formation of the four off-center peaks of the local Nusselt number at the impingement surface.更多还原