【作者】 孙勇；

【导师】 何永森；

【作者基本信息】 湘潭大学 ， 计算数学， 2005， 硕士

【摘要】 用DHR 型k-ε紊流模型及其壁面函数·BFC(边界拟合曲线坐标变换)法,对总扩散角为8~°、扩散度为4 的锥形渐扩管路内完全发展的不可压粘性紊流场进行了数值模拟。所研究的紊流在入口的雷诺数为2.93 ×10~5和1.16 ×10~5。在径向适体均匀网格系统、近壁密集型径向适体非均匀网格系统、成倍增加网格数和对流项在固体壁面处不同的差分方法等计算条件下分别给出了时均流速u 、紊流动能k 分布的计算结果,并分别与实验结果进行比较和分析;同时给出了锥形渐扩管内各主要流动参数u 、k 、紊流耗散率ε和涡动粘性系数νt的分布。研究在不同计算条件下对计算精度和运算效率的影响程度,为工程技术实际应用提供依据。更多还原

【Abstract】 Fully developed incompressible turbulent flow in a conical diffuser having a total divergence of 8°and an area ratio of 4:1 has been simulated by a DHR k-εturbulence model and it’s wall function·BFC(Boundary-Fitted Coordinates) method. The research has been done for pipe entry Reynolds numbers of 2.93 ×10~5 and 1.16 ×10~5. The calculated results of the distribution of the mean flow velocity u and turbulence energy k has been given out under the different calculated conditions respectively, such as radial fitted-body uniform grid system, near wall denseness model radial fitted-body non-uniform grid system, increasing twofold grid numbers and difference methods on the solid wall of the convection terms, and they were analyzed and compared with the test results respectively; At the same time, the distribution of the main parameters that flow u , k , turbulence dissipation ratio εand eddy viscosity coefficient νt are given out in conical diffuser. The effect degree of the calculated degree and operation efficiency has been studied under the different calculated conditions, and they have offered reference for engineering techniques actual application.更多还原