分流叶片长度及周向偏移量对ORC向心透平性能的影响

Effects of Splitter Blade Length and Circumferential Offset on the Performance of ORC Radial Inflow Turbine

利用分流叶片能有效改善叶片通道内的流动阻塞问题,降低流动损失。针对某带分流叶片的有机朗肯循环(ORC)向心透平,研究了不同分流叶片长度和周向偏移量对透平性能的影响,对不同叶片布置方案进行数值模拟,分析了内部流动状况、叶片载荷和损失分布。结果表明:分流叶片能有效削弱通道中的涡流,改善流动状况,使通道内部的压力分布合理;同时在一定程度上分担了主叶片的载荷。与分流叶片长度系数相比,周向偏移量对熵产率的影响较为明显;随着长度系数和周向偏移量的增加,高熵产率范围和总压损失系数均呈现先减后增的趋势,等熵效率的变化则相反,当l=0.5、d=0.5时等熵效率最大,为91.26%,而功率与叶片长度大体呈正相关;将长度系数和周向偏移量分别控制在0.5~0.6时,能保持较为理想的流动状况及叶片载荷分布,高熵产率范围较小,有利于透平性能的提升。

Using splitter blades can effectively improve flow blocking problem in blade channel and reduce flow loss.Aiming at an ORC radial inflow turbine with certain splitter blades,the influence of different splitter blade lengths and circumferential offset on turbine performance was studied.And internal flow conditions,blade load and loss distribution were analyzed by numerical simulation of different blade layout schemes.Results show that the splitter blade can effectively weaken the vortex in the channel,improve the flow condition,and make the pressure distribution inside the channel reasonable.At the same time,it can share part load of the main blade to a certain extent.Compared with the length of the splitter blade,the influence of circumferential offset on the distribution of entropy yield is obvious.With the increase of length and circumferential offset,the high entropy yield range and total pressure loss coefficient show a trend of first decreasing and then increasing,and the change of isentropic efficiency is the opposite.When l=0.5 and d=0.5,the isentropic efficiency is the largest by 91.26%,and the power is roughly positively correlated with blade length.When the length coefficient and circumferential offset are controlled between 0.5-0.6,the ideal flow condition and blade load distribution can be maintained,and the high entropy yield range is small,which is conducive to the improvement of turbine performance.