不同偏流角下潮流能水轮机水动力特性与熵产率分析

Analysis of Hydrodynamic Performance and Entropy Production Rate of Tidal Current Turbine Under Different Deviant Angle

采用CFD与熵产理论相结合的手段,分析了不同偏流角对潮流能水轮机水动力特性的影响,发现偏流使无导管水轮机和导管水轮机输出功率及轴向推力均不同程度地降低,偏流20°时,两者功率最大下降率分别达到30.6%、16.8%,转子轴向推力最大下降率分别达到30.2%、19.8%。由于导管的聚流效应,不同偏流角下导管水轮机相比无导管水轮机仍保持较高的输出功率。在处于低叶尖速比时,直接耗散熵产损失对水轮机能量获取影响较大,此范围内总熵产损失较低;在高叶尖速比时,湍流耗散损失对水轮机能量获取影响较大,此范围内总熵产率随叶尖速比的增加而快速上升,导致水轮机输出率随叶尖速比的增加而不断下降。

The hydrodynamic performance of a tidal current turbine with different deviant angles is studied by the combination of CFD and entropy production theory. The results show that the output power and axial thrust of the ducted turbine and the bare turbine are reduced under action of the bias current. When the deviant angle is 20°, the maximum power drop reaches 30.6% and 16.8% respectively, and the maximum decrease of axial thrust is 30.2% and 19.8% respectively. Compared with the bare turbine, the ducted turbine with different yaw angles still maintains higher output power due to the accumulation effect of duct. When the ratio of blade tip is low, the loss of direct entropy production has a great impact on the energy acquisition of the turbine, and the total entropy loss is lower in this range;In the case of high tip speed ratio, the turbulence dissipation loss has a great impact on the energy acquisition of the turbine, and the total entropy production loss increases rapidly with the rising of tip speed ratio, which is contributed to the decrease of output power of the turbine with the rising of tip speed ratio.