一、引言 近年来对径流透平的科研工作已有较多的开展,以期获得新的设计计算方法,改善透平的性能.但蜗壳的设计,至今仍基于一元流动的假设,认为导向叶片进口流场是沿周向均匀的,这种假定不符合实际情况.实际上,由于气体的粘性,在蜗壳内壁面上将产生附面层,此附面层沿气体在蜗壳内的流向而发展.蜗壳壁面上,由于压强与气流的离心力不平衡而造成二次流.再加蜗壳进口本身流场不均匀的影响,蜗壳中的流动明显为三元流 I. INTRODUCTION Scientific research work on runoff turbine has been carried out more and more in recent years in order to obtain new design and calculation methods to improve the performance of the turbine.But the design of the volute is still based on the assumption of one- In fact, due to the viscous nature of the gas, an adherent layer is created on the inner wall of the volute which flows along the flow of gas in the volute And the development of the volute wall, due to pressure and airflow imbalance caused by the second flow, coupled with the volute itself is not uniform flow field inlet, volute flow is obviously three yuan flow