| Reverse jet as an efficient flow control technique for increasing flow resistance,this paper analyzes an experimental study on the scale-up straight labyrinth seal model,focusing on the influence on the internal flow field of labyrinth seal by reverse jet.First of all,through the analysis of the internal flow field of seal labyrinth and four kinds of seal characteristics,the results show that: reducing ventilation effect,increasing the cavity dissipation effect and increasing friction effect are the three ways to enhance seal effect of labyrinth seal.Based on analysis of reserve jet flow mechanism we can know that the method can achieve the above three objectives.A 2D straight labyrinth seal experiment with reverse jet has been designed and proceeded,in order to observe the effect of using jet to increase flow resistance more intuitively,using PIV to obtain the flow field with reverser jet under three different jet angles and three different jet positions.Based on the experimental results,the effect of jet angle and jet position on seal performance is analyzed,the results show that jet positions determine the size of counter vortex and the direction of leakage flow entering the second teeth,and jet angels determine the effect of the jet on the leakage flow.A numerical simulation study for jet positions has been done,the results show that all different jet positions can enhance seal effect of labyrinth seal;through the numerical simulation of 18 kinds labyrinth seal model with reverse jet based on orthogonal method,the results show the primary and secondary sequence of the factor for seal: cavity width> tip clearance> jet width> jet angle> tooth top thickness> cavity depth> jet position.Last,make a detailed analysis of jet angel and jet position,the results show that: the smaller the jet angel,the better the sealing effect,when the jet position in the middle of the first cavity,the sealing effect is best,and when the jet angel is 45°,sealing performance increased by 11.5%. |
PDF Full Text Request