Experimental And Numerical Research On The Influence Of Cooling Air Ejection On The Aerodynamic Performance Of Gas Turbine

As an important means of thermal protection for turbomachinery components,gas cooled turbine technology is widely used in gas turbine cascades,Air-cooled turbine technology is widely used in gas turbine cascades.The three-dimensional flow field in the turbine cascade is very complex,and the flow distribution of the cascade can be changed by the cold air injection into the mainstream,which causes the change of the aerodynamic performance of the cascade.It has a great significance to study the effect of the cold gas ejection on the aerodynamic losses of the turbine cascade.In this paper,the experiments of fan turbine cascade combined with numerical simulation methods are used to study the aerodynamic effect of cold air ejection on the film hole and trailing edge slots of a transonic turbine stator cascade and rotor cascade blade in different outlet conditions.In the static cascade experiment,the gas film holes are set at the leading edge,suction surface and pressure surface of the blade,and the PSEJ structure is set at the trailing edge.The comparison and analysis of the experimental results under the no cold air ejection and the two different air flow ejection were carried out under the working conditions of ensuring the export Maher number are 0.9,1 and 1.05.In the rotor blade experiment,only the PSEJ structure was set at the trailing edge.Under the condition of ensuring the export Maher number are 0.9,1 and 1.05,the experimental results of cold air injection and cold air injection are compared and analyzed.Using the CFD numerical calculation method which were verified by the experimental data to simulate the flow in more air injection conditions,which makes up the limitation of the experimental means to obtain the too little flow field data,and focuses on the influence of the air flow rate on the aerodynamic loss performance of the transonic turbine cascade.Through the comprehensive comparison of the experimental and numerical simulation results under different conditions,it is found that the air flow rate has a great influence on the energy loss of the transonic turbine cascade,and the influence of the air flow rate on the aerodynamic loss of the cascade is also very different under the different outlet Mach number.The cold air ejection(outlet Ma=1.0)at the leading edge of the stator blade is a reverse injection,and the energy loss of the cascade will increase monotonously with the increase of the main flow ratio.When the cold air ejected on the leading edge/trailing edge/suction surface/pressure surface of the stator blade,the average energy loss of the cascade is reduced firstly and then increases with the increasing of the main flow ratio of the cooling air,whether it is the subsonic(Ma=0.9)or the supersonic(Ma=1.05)flow.When the cold air ejected on the leading edge/trailing edge/suction surface/pressure surface of the stator blade,the influences of the cold air on the aerodynamic loss(blending losses,secondary flow losses,shock losses,wake losses,etc.)in various regions of the cascade are different and affect each other,the loss of the whole turbine cascade is a comprehensive result of the loss of each part.The influence of cold air on the throat shock and tail shock and the influence on the wake are the main factors influencing the aerodynamic losses when the cold air ejection at the tail edge of the rotor blade.