Experimental Study On Aerodynamic Performance And Loss Prediction Of High Efficiency Combined Cycle Turbine Blades

It is very important to develop an efficient steam turbine generator set for the steamgas combined cycle to improve the power generation efficiency.At the same time,optimizing the aerodynamic performance of blades and reducing blade profile loss have important engineering application value for steam turbines.In this thesis,the aerodynamic performance and loss mechanism of the rotor and stator blade profile under variable impact Angle are studied by blowing test and numerical simulation of the rotor and stator blade plane cascade and annular cascade.Through Reynolds number numerical simulation,the stator blade was verified based on entropy loss prediction method,and the classical loss prediction model was proposed to fit and modify,so as to obtain the loss prediction model generally applicable to the cascade wind tunnel test with basically the same test conditions.It is very important to develop an efficient steam turbine generator set for the steamgas combined cycle to improve the power generation efficiency.At the same time,optimizing the aerodynamic performance of blades and reducing blade profile loss have important engineering application value for steam turbines.In this paper,the aerodynamic performance and loss mechanism of the rotor and stator blade profile under variable impact Angle are studied by blowing test and numerical simulation of the rotor and stator blade plane cascade and annular cascade.By changing Reynolds number conditions,the stator blade was verified based on entropy loss prediction method,and the classical loss prediction model could be fitted and modified to obtain a loss prediction model applicable to cascade wind tunnel tests under the same test conditions.First of all,wind tunnel tests were carried out on three high cross-section profiles of the 12 th stage dynamic and stator blades with variable Angle of impact(0°,±10°,±20°),and the static pressure coefficient distribution,total pressure coefficient distribution and outlet flow Angle distribution of the cascade on each plane were measured under different Angle of impact.The test results show that both static and dynamic blades are designed for rear loading.The dynamic blade has a greater degree of rear loading than the static blade,the lowest pressure point is more backward,and the adaptability to the variable impact Angle is stronger,and the loss is the minimum when the negative impact Angle is small.Secondly,the blowing test of annular cascade is carried out on the stator blades,and the variable impact Angle numerical simulation is carried out on the stator blades.The test results are compared with the numerical simulation results and verified.The comparison results show that the stator blade adopts the end-bend design,which improves the aerodynamic performance of the cascade.The radial pressure gradient is small,the inverse pressure gradient is short,and the flow loss is well controlled.The stator blade is more sensitive to the positive impact Angle.With the increase of the impact Angle,the loss of the upper passage vortex increases especially,and the passage vortex gradually moves away from the endwall.In the actual installation,the inlet flow at the blade root with zero or small negative impact Angle can be given priority.Finally,the variation law of profile loss with Reynolds number is studied by numerical simulation,and the loss prediction method based on entropy generation is verified,which shows that the prediction of profile loss based on entropy generation is reliable within the allowable error range.The loss prediction model of stator blade profile is predicted by the classical loss prediction model,and the variable Reynolds number numerical simulation of other typical turbine cascades can be carried out to modify the classical loss prediction model and obtain a loss prediction model applicable to cascade wind tunnel tests under the same test conditions.