Study On The Influence Of Stator Leading Edge Tip Cutting On Aerodynamic Performance Of Planar Cascade

Although the leading edge of the compressor blade is small in size,the change in shape will affect the aerodynamic performance of the whole cascade.The blade tip-cutting design is a blade optimization method.Some researches have been carried out on the leading edge,trailing edge of rotor blade and trailing edge of the stator blade.However,few studies carried out on the leading edge of the stator blade tip-cutting design.In this paper,the NACA-K48 high-load diffuser stator is taken as the research object,and the leading edge is designed with different sizes of tip-cutting.Numerical simulation is carried out by using CFX numerical calculation software.By comparing and analyzing the changes in the distribution of total pressure loss coefficient,static pressure ratio,pressure coefficient,Mach number and limit streamline,Aerodynamic performances of tip-cutting and bilateral tip-cutting of blades with different sizes are compared,and the best leading edge tip-cutting scheme is explored.Firstly,Numeca is used to mesh the cascade runner,and different mesh numbers are selected to verify the grid independence,and the results are checked with the experimental results to ensure the accuracy of the numerical simulation results.The numerical analysis of the prototype cascade shows that:under the same Mach number,the flow loss at-60 angle of attack is the lowest,the loss at other angle of attack increases,the static pressure ratio increases with the increase of the angle of attack,and the performance deteriorates is more serious at the large negative angle of attack;under the same angle of attack,loss increases with Mach number,but the static pressure ratio decreases,and the flow distribution of low Mach number is better.Then,the tip cutting design is carried out at the tip of the stator blade leading edge,firstly select 3 groups of different axial tip-cutting dimensions(3.3%,6.7%,and 10.0%chord length),compare with the prototype cascade under different working conditions(0.7Ma with-9°～0° angle of attack,0.5Ma with-12°～0° angle of attack).The results show that the blade tip-cutting design can reduce the flow loss and increase the static pressure ratio at the design angle of attack and the negative angle of attack,under the condition of slightly increasing the blade load capacity.But the flow condition at the positive angle of attack is deteriorated.Considering comprehensively,the effect of 3.3%chord length axial cutting size is better.Based on the axial cutting dimensions,3 different radial tip-cutting dimensions(5%,10%and 20%leaf height)were selected.The results show that the smaller radial tip-cutting size will deteriorates cascade performance to some extent.The larger the radial tip-clipping size is,the greater the performance improvement range is under the negative and design angle of attack,but the deterioration degree of positive angle of attack is also severe.In the end,it is considered that the design of axial cutting 3.3%chord length radial cutting 10%and 20%leaf height had better effect.Finally,on the basis of the tip-cutting design of the blade tip,the double side tip-cutting design of the leading edge was carried out,and a simple comparison was made with the trailing edge sweeping design.The results show that the flow loss of design angle of attack and negative angle of attack can be greatly reduced and the static pressure ratio can be increased under the condition that the performance deterioration range is small under the condition of positive angle of attack.Under the condition of this paper,the trailing edge sweeping design can only minor improve the aerodynamic performance of the cascade(reduced the total pressure loss and increase the static pressure ratio),and the trailing edge sweeping will increase the axial dimension of the blade.Therefore,the double side tip-cutting of the leading edge had better aerodynamic performance improvement effect.