Test And Calculation Analysis Of The Impact On Stage Performance For Suction And Leakage Flow Between Stator And Rotor In A Turbine Stage With Positive Stator

Combining the experiment with numerical analyzing, the air turbine test and numerical simulation were studied and analyzed in detail for the action turbine stage with positive curved stator blade. More attention were paid for analyzing the flow phenomenon at interstage root while suction or leakageage occurred at the root of stator and rotor blade and its affection to stage performance.The stage performance test was carried out on air turbine test bed for the stage with positive curved stator blade. The experiment included two parts: (1) with constant pressure ratio and without suction or leakageage, the stage efficiency and stage discharge coefficient, as well as reaction varied with the velocity ratio, (2) with constant pressure ratio and at the velocity ratio of 0.5, the stage performance affected by the changing of suction or leakageage flow at interstage root.Numerical investigations were carried out for the experimental model stage by NUMECA computation fluid dynamics software, the content of the numerical simulation was basically the same as that of the experiment, and the results were analyzed in comparison with the experiment ones. In order to make our knowledge to a depth about the flow of suction or leakage at interstage root for the stage with positive curved stator blade, the numerical simulation of the turbine stage with straight stator blade having the same profile as the positive curved stator blade was carried out, and the result was compared with that of the turbine stage with positive curved stator blade.By means of experimental investigation and numerical simulation, the stage performance of the stage with positive curved stator blade and the suction or leakageage phenomenon in interstage chamber and its affection to the stage performance were analyzed. The results showed that, the suction or leakage in interstage chamber have a great effect on turbine stage performance. The gland leakage-off of the diaphragm flowing into the main stream will interfere with it severely, and cause a great adverse effect on turbine stage performance.A little quantity of leakageage can make the inlet boundary layer of the rotor blade thinner, thus, the end loss at the root of the rotor blade will be reduced and the stage efficiency will be increased.The obtained results of this thesis are of important academic value for the investigation on the desigh of gland seal of diaphragm,balance hole, and the application of positive curved stator blade. In addition, it is also of engineering and practical value for the design and optimization of through-flow of steam turbine.