超低水头轴流式水轮机CFD优化及流动特性研究

CFD Optimization and Study of Flow Characteristics of Axial Flow Turbine with Ultra-Low Head

结合某水电站改造要求,研发了一种设计水头为2.75m的超低水头轴流式水轮机并对其性能进行优化,以达到有效利用低水头水力资源的目的。基于不可压缩连续方程及雷诺时均Navier-Stokes方程,采用Spalart-Allmaras湍流模型和SIMPLEC算法对轴流式水轮机进行三维全流场数值模拟,分别分析了轴流式转轮叶片翼型、轮毂比、导叶开度及安放角对水轮机性能的影响,并对最优模型进行实测验证。结果表明,在满足设计水头为2.75m的情况下,选用配置叶片B、轮毂比为0.30、叶片相对安放角为-2°的水轮机,当导叶相对开度为0°时,装置水力损失最小,最高效率达83.7%,且数值模拟计算所得出力与实测结果误差小于0.99%,表明基于CFD的数值模拟对超低水头轴流式水轮机的性能预测精度较高。

Combined with the reformation requirement of power station,a super-low water head of axial flow turbine with 2.75 mdesign head was developed and its performance was optimized to reach the purpose of utilizing the low head hydraulic resource effectively.Based on the incompressible continuous equation and Reynolds-averaged Navier-Stokes equation,three-dimensional flow passage numerical simulation of axial flow turbine was conducted by using Spalart-Allmaras turbulence model and SIMPLEC algorithm.The influences of blade airfoil,hub ratio,vane opening and blade setting angle on the turbine performance were analyzed.The optimal model was validated through turbine test.The results show that when the relative opening of the vane is 0°,the turbine has least hydraulic loss and the efficiency is 83.7%at the conditions of the turbine with blade B,0.30 hub ratio and-2°blade setting angle.The output error between numerical simulation and test is smaller than 0.99%.It means that performance prediction of super-low water head of axial flow turbine with CFD numerical simulation has high precision.