Design And Optimization Research Of The Vane-end Zone On Variable Geometry Turbine

As gas turbine being an important energy device,now it is now in the country's account for an increasing proportion of industrial production. For the gas turbine, gas turbine in part load performance is a very important influence factors in the practical work.In order to solve this problem,nowadays the researchers make the use of the variable geometry turbine technology to design variable condition of the turbine performance.Through the technology of the variable geometry turbine, the performance of turbine in the different working conditions can be operating under good conditions. However, due to the variable geometry turbine introducing clearance leakage loss,so it will make the difference of the blade end zone flow field and mainstream zone flow field. So now, in the field of variable geometry turbine, the improvement of variable geometry turbine performance is an important research focus. Now in order to improve the performance of the turbine, it need to know the principle of tip leakage flow in variable geometry turbine, in order to find effective control the clearance leakage losses, reducing clearance leakage loss.This article obtains from the experiment, through the variable geometry turbine plane cascade flow field in experimental analysis, a passive control scheme - flat tip and cavity tip for numerical simulation research. Through the analysis of of these two kinds of solutions,,it finds that cavity tip of end zone can have inhibitory effect on the clearance leakage flow.Then based on the experimental results, this paper in order to end zone optimization structure further study, in addition to slot structure of labyrinth seal structure and honeycomb seal structure on the district conducted a detailed study of the influence of the leakage loss. Through comparison and analysis, it can be found that under different opening cavity tip of end zone adding the labyrinth seal and add the honeycomb seal structure are to inhibit the action of the tip leakage flow, and honeycomb seal effect on inhibition of leakage flow is better. And in three kinds of honeycomb seal structure, the rotating shaft in front of the honeycomb seal structure has a stronger inhibitory effect on the clearance leakage flow.According to the research of the planar cascade end zone to optimize the structure, this article will be in large meridional expansion variable geometry turbine side area optimization structure further practical research. Based on three kinds of the opening, the analysis of the variable geometry turbine flow field under different structure, it found that through the influence of variable geometry turbine side area in end of honeycomb seal processing for flow field.,the articles shows that under different working conditions under the premise of traffic basic unchanged, The efficiency of the turbine is increased with the increase of compression ratio decline after rising first, and hub for the efficiency of the honeycomb seal treatment is higher than other side area structure optimization. The honeycomb seal of the hub can make a great contribution to control the leakage vortex and passage vortex, and the adaptability of angle attack is great as well.