三分支排气管三维定常流计算中的几个问题

为了以ＫＩＶＡ程序为基础来计算分支排气管内的气体流动，对ＫＩＶＡ程序作了若干改进，如增加了处理进、出口边界的功能，以适应开口热力系统流动的计算；在压力亚循环阶段和对流通量计算过程中，引入面中心速度求解动量方程，使流场解的特性得到很大的改善；采用分块耦合方法生成三分支排气管三维贴体网格；利用时间相关法设置定常流动收敛准则等。最后，采用改进的ＫＩＶＡ求解分支排气管定常三维流场，计算结果与试验结果吻合良好，说明ＫＩＶＡ的改进是成功的。改进的ＫＩＶＡ具有较高的模拟精度和较强的通用性，可以用于具有复杂形状的开口系统的流动计算

Several Problems About the Computation of Three-Dimensional Steady Flows in the Three-Branch Exhaust Pipe

In order to use KIVA to simulate the flows in the exhaust manifold,the inflow and outflow boundaries are built in the code.During the acoustic subcycling and in the convective fluxing of quantities,the idea of face centered velocities is introduced to solve the momentum equation,and the behavior of solutions is well improved.The multiple block coupling method is used to generate 3 D body fitted grid for the three way branch pipe.The steady convergence criteria are set up using the time marching method.The modified KIVA is adopted to compute the steady 3 D flow field in the pipe.The computing results are in good agreement with the experimental ones,which means that the modifications to the KIVA are successful and the modified code has a higher precision and wider applicability and can be used in the open flow system with complex configuration.