为了提高液力透平的效率,设计前弯和后弯2种形式的叶轮,通过理论分析、数值计算以及实验研究的方法对其进行分析.应用流场分析软件ANSYS CFX分别对具有2种形式叶轮的液力透平进行全流场数值计算与分析,得到2种液力透平外特性曲线的差别,并分析2种液力透平叶轮内部流场流动规律.研究结果表明:前弯形叶轮在最高效率点的流量、扬程、轴功率和效率分别比后弯形叶轮高24.45%,29.80%,68.95%和4.38%;前弯形叶轮高效点以及高效点之后的流量效率(η-Q)曲线高于后弯形叶轮的流量效率曲线,流量扬程(H-Q)曲线低于后弯形叶轮的流量扬程曲线,2种形式的叶轮轴功率相差不大;前弯形叶片叶轮内部速度梯度小于后弯形叶片叶轮的内部速度梯度,前弯形叶片叶轮内部水力损失较少;实验结果与数值预测结果相吻合,验证了数值计算可以用来对液力透平进行优化设计.%To improve the efficiency of hydraulic turbine, forward and backward-swept impellers were designed. Theoretical analysis, calculation simulation and experimental research were carried out on forward and backward-swept impellers. Performance difference of these two impellers was found by adopting computational fluid dynamic software ANSYS CFX. The internal fluid flow law in impeller was analyzed. The results show that compared with that of backward-swept impeller the flow rate, head, shaft power and efficiency at the best efficiency point (BEP) of forward swept impeller are increased by 24.45%, 29.80%, 68.95% and 4.38%, respectively. After BEP, turbine's η-Q curve of impeller with forward-swept impeller is higher and H-Q curve is lower than that of backward-swept impeller. The variation of shaft power of these two impellers is small. Internal velocity distribution shows that gradient of velocity in forward-swept impeller is smaller than that in the backward-swept impeller. And hydraulic loss in forward-swept impeller is less than that in the backward one. The coincidence of experimental and numerical results demonstrates that CFD can be used in the performance prediction and optimization of hydraulic turbine.
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