双层垂直轴水轮机性能计算的当量密实度法

Equivalent-solidity method for performance analysis of double-H type vertical-axis tidal current turbine

为解决流管模型在双层垂直轴水轮机性能计算中的数值发散问题,提出了一种流管模型的修正方法——当量密实度法。当量密实度法将双层垂直轴叶轮的计算与单层垂直轴叶轮的计算进行类比,将双层叶轮变换成为单层叶轮,减少了流管模型的计算盘面数,从而避免了数值发散问题。先利用某型单层垂直轴水轮机的实验数据和CFD(computational fluid dynamics)计算数据,对流管模型数值程序的有效性进行了验证,同时分析了流管模型在计算双层叶轮性能中存在的困难。给出了当量密实度法的理论,并利用CFD计算结果对新方法的数值程序进行了验证,对结果进行了分析。分析结果表明,当量密实度法的计算结果与CFD计算结果基本吻合,当量密实度法可以应用于双层垂直轴水轮机的性能估算。

; To solve the numerical divergence of the stream tube model in the performance calculation of double-H type vertical-axis tidal turbines, an equivalent-solidity method, which is a correction method for modifying the stream tube, was proposed. The equivalent-solidity method made an analogy between single-H type and double-H type turbines and converted a double-H type turbine into a single-H type turbine. This approach decreased the number of disks of the stream tube and avoided numerical divergence. The experimental and CFD calculation data from a single vertical axis turbine validated our numerical programs. Then, problems of the numerical divergence of the performance calculation of the double-H type turbine were analyzed. Therefore, the basic theory of the equiva-lent-solidity method was proposed; this theory validated the results of this new program based on the CFD calcula-tion results. Comparison results show that the equivalent-solidity method agrees well with the CFD method and can be used to estimate the performance of double-H type vertical-axis tidal turbine.