CFD法研究多喷嘴冲击式水轮机的射流干涉

为提高冲击式水轮机的比转速和出力,通常采用增加喷嘴数的办法,然而增加喷嘴数会引起射流干涉,降低水轮机的水力效率.文中研究了射流干涉的产生机理,通过计算相邻两射流之间的动画单元数、水斗接受最后一滴射流的动画单元数、发生射流漏损时无效射流恰与水斗分离的动画单元数以及两相邻射流相交的动画单元数,提出了相邻两射流间发生干涉的判别式.利用所提出的判别式预测了不同喷嘴数和水斗数时冲击式水轮机的射流干涉情况,所得结果证明了判别式的有效性.

CFD-Based Investigation into Jet Interference in Multi-Nozzle Pelton Turbines

In order to increase the specific speed and force of Pelton turbines,the multi-nozzle configuration is commonly adopted.However,the addition of nozzles leads to the jet interference,which reduces the efficiency of Pelton turbines.In this paper,the reasons for jet interference are analyzed.By calculating the numbers of four kinds of threshold frames,that is,the frame when the bucket meets the next jet,the frame for the last capture of outermost streamline of jet by a bucket,the frame for the occurrence of ineffective jet by non-capture and the frame at the cross point of two jets,two criteria are presented to predict the occurrence of interference for two adjacent bare jets.The criteria are then used to predict the bare-jet interference in the Pelton turbines with different nozzles and buckets,whose effectiveness is finally verified by the predicted results.