差分格式对柴油机进气流动模拟计算结果的影响

研究差分格式对柴油机进气流动模拟计算结果的影响. 利用三维计算软件FIRE,对双进气道柴油机进气道的稳流试验进行了模拟计算. 对动量矩方程、连续性方程、湍流方程的数值解法使用了不同的差分格式,对比不同条件下进气的质量流量和涡流转速,并和试验结果进行对比. 结果表明,不同情况下质量流量的计算值相差很小,和试验值之间的误差较小;涡流转速的计算结果相差很大,当选择高阶差分格式,同时选择适当的混合因子时,涡流转速的计算值和试验值吻合得很好.

Effect of Difference Scheme on the Simulation Results of Intake Flow in Diesel Engine

The effect of difference scheme on the simulation results of intake flow in a diesel engine was studied.The three-dimensional simulation of intake flow of a double-intake-port diesel engine was performed by using a three-dimensional software FIRE.Various difference schemes were used to solve the momentum equation,continuity equation and turbulence equation.The computed mass flux and the swirl rotate speed were compared under different conditions.And the computed results were compared with the experimental results.Results indicated that the differences among the computed values of mass flux under the condition of various schemes are very small.But,the differences among the computed values of swirl rotate speed under the condition of various schemes are very big.When the high order difference schemes and appropriate blend factor are adopted,the errors between the computed results and experimental results will be very small.