三分支管3维湍流流场的模拟研究

Study of Three Dimensional Turbulent Flow in Manifold Junctions

本文在网络生成、边界条件、收敛准则等方面对ＫＩＶＡ程序进行了改进，以便模拟三分支管内气体流动；利用３维粒子动态分析仪（３Ｄ－ＰＤＡ）测量了矩形截面三分支管试验件的３维速度场，以验证改进后的程序软件的可靠性；最后，以某一型号发动机的ＭＰＣ排气系统为例，在只有支管进气和支管总管都进气两种情况下，模拟了ＭＰＣ模件三分支管的３维定常湍流流动。由此揭示了ＭＰＣ模件三分支管３维湍流的流动特性，并分析了引起其排气能量传递损失的主要因素。

The modification to KIVA program in grid generation,boundary conditions and convergence criterion has been made to simulate turbulent flow in manifold junctions.The three dimensional velocities of the manifold junction with a rectangular section were measured by use of three dimensional particle dynamic analyzer (3D PDA) to verify the modified KIVA program.In the last,taking a MPC exhaust manifold junction of a model engine for example, the authors simulate numerically its three dimensional steady turbulent flowfield, With that gas enters only at the entrance of the side duct, or gas enters simultaneously at the entrances of the side duct and the main duct.From the simulation results of the flowfields, the properities of three dimensional steady turbulent flow in MPC exhaust manifold junctions are revealed, and the factors which may causing its flow loss are analyed.