水轮机尾水管三维湍流数值模拟

Three Dimensional Turbulent Flow Simulation through a Hydraulic Turbine Draft Tube

利用κ－ε两方程湍流模型建立了适应水轮机尾水管三维湍流的控制方程组，推导出用爱因斯坦求和下标所表示的三维控制方程在贴体坐标下的张量形式。应用有限差分法对控制方程进行了离散，编制了三维湍流的计算程序，计算方法和程序用三维弯管湍流的试验数据进行了验证。对尾水管的内部流场进行了计算，得到了尾水管中压力场及速度场分布以及尾水管中的回流和二次流现象。

This paper presents a practical k-ε two equations' turbulence model through a draft tube of the hydraulic turbine and has built up a set of governing equations for the turbulent flow.Tensor representation of the governing equations under body fitted curvilinear coordinate systems is derivedby using Einstein's expressing method.The technique of the finite difference approximation is used to discrete the governing equations and to develop computer program.The computational method and computer program has been verified by the comparison between calulation results and experimental data.As the results of the present caluclation,the velocity and pressure distributions as well as the location of the backward flow and the second flow caused by pressure distribution of the inner flow through the tube are obtained.