Experimental Study On Boundary Layer Characteristics Of Suction Surface Of Low-pressure Turbine Blade

This paper is based on the plane cascade experiment of a low-pressure turbine simulating upstream wake interference,aims to understand the characteristics of the boundary layer on the suction surface of the low-pressure turbine blade,an wind tunnel of meets the experimental conditions and some other hydrodynamic experimental conditions is designed and constructed.An experimental study on boundary layer characteristics of suction surface of low pressure turbine blades is carried out on the experimental platform.In the early stage of the experiment,a lot of preparatory work has been done,including the calibration of hot-wire probe,the positioning of measuring points on suction surface of blade and the design of automatic displacement route of hot-wire probe.In the process of design and construction of wind tunnel,the design effect is predicted by numerical simulation method.In the process of building,it is inevitable that there will be some errors of view,so after the completion of the construction process,the experimental flow field is further optimized by adjusting the upper and lower walls of the experimental section through the measurement of the flow field quality in the experimental section of the wind tunnel.This experiment mainly carries out the measurement of flow field parameters without wake and with upstream wake.Through the analysis and calculation of the experimental results,it is found that the boundary layer on the suction surface of the low pressure turbine blade gradually becomes thicker without upstream wake.With the downstream flow,the velocity of the airflow fluctuates greatly,the turbulence increases sharply at a certain position,and the separation of the boundary layer occurs downstream.In the case of upstream wake,the upstream wake enters the channel with the flow of airflow and interferes with the flow field in the channel.With the downstream movement,the parameters such as velocity and turbulence do not change sharply,no separation bubble.The separation of boundary layer did not occur,which indicated that the upstream wake induced transition of boundary layer and inhibited the separation of boundary layer.