复杂边界通道内的三维紊流数值模拟

【作者】 郭鹏程；

【导师】 牛争鸣；

【作者基本信息】 西安理工大学 ， 水力学及河流动力学， 2000， 硕士

【摘要】 本文采用以压力为求解变量的原始变量法，对雷诺平均后的N-S方程，用有限差分法离散，并用压力速度校正法求解。 通过对流场预测方法及紊流模型的分析评价，指出用数值模拟的方法研究湍流问题已成为解决工程问题的重要手段与有效途径，并选定标准k-ε紊流模型作为本文的计算模型，对于固壁附近粘性底层中的流动，采用壁面函数法。 本文作为开发叶轮机械流场计算程序的准备工作，算例结构具有强烈的弯曲和扭转的特点，故采用解Possion方程的方法生成计算网格，以保证生成的网格具有良好的贴体性、正交性和光滑性。 本文分别计算了Taylor弯管、后台阶突扩通道和旋转方直通道的流动，并和测试结果或文献成果进行了比较，进而计算了形状具有弯曲、强扭、渐扩和旋转特点的复杂通道，结果具有合理性，说明了本程序的通用性和可行性。更多还原

【Abstract】 On the basis of the rule of Reynolds-averaged, the control equation forincompressible flow are obtained. The numerical procedure is essentially pressure-correction type of finite difference formulation on general curvilinear coordinates systembased on pressure as solving variable. By analyzing and commenting on the methods of flow field prediction and a varietyof turbulence models, this paper directs that numerical analysis is a kind of important andeffective method solved the engineering problems. And standard k-ε turbulence modelis applied to estimate the Reynolds stress of Reynolds averaged N-S equation. Wall-function is adopted for laminar sublayer near the surface of the solid wall.This paper is a part of developing procedure analyzing flow fields in runner ofturbine, the shape of the duct calculated is characterized by its complex and twist, so thePoisson equations are solved to generate body-fitted grid in order that being generatedgrids are of quite smoothness and orthogonality.Flows in Taylor curved duct, flows over a backward-facing step and flows in rotatingducts are calculated respectively, and the calculation results close to the availableexperimental datum. Then the flow fields in a sophisticated configuration are calculated.The results are shown that this procedure has a strong ability to calculate the flow-field insophisticated configurations.更多还原