| In the actual operation process of gas turbines,it is often not the same as in design,development and testing.The intake air is usually disturbed by various disturbances,resulting in an uneven flow field.Intake distortion has great influence on compressor and even gas turbine,including aerodynamic performance,stability margin and flow field.In this paper,NASA Stage35 is taken as the research object,and its three-dimensional full channel numerical calculation is carried out.The total inlet pressure distortion is numerically simulated by changing the distortion intensity and changing the distortion position.The characteristic parameters were analyzed,and the flow field was observed and compared.Finally,the specific influence of total inlet pressure distortion on the working characteristics and flow field of transonic axial compressor was sorted out.The main research contents of this paper are as follows :1、The model is meshed and verified,and the three-dimensional full-channel NASA Stage35 compressor under uniform inlet condition is numerically simulated.Under the condition of uniform intake,the fluid form periodic changes on the circumferential cross section of the entire flow channel from the compressor inlet to the outlet.The losses at near-leaf top,edge of each single channel were greater than those at other positions;There is a small range of shock wave in the front edge of suction in the high part of 0.1 blade.The entropy loss of stator suction surface is large.2、The numerical simulation carries out for the distortion of inlet total pressure with distortion angle of 30°and distortion intensity of 0.2.The inlet distortion area moves downstream of the set position and the distortion range increases;The inlet total pressure distortion causes the total pressure loss,entropy loss and relative Mach number change.The distortion of inlet total pressure also leads to the generation of shock waves in the flow channel between rotor blades and the separation of the inner boundary layer in the static blade flow channel at the height of 0.95 blade.3 、 The numerical simulation and comparative analysis of the inlet total pressure distortion with three different distortion intensity(DI = 0.1,DI = 0.15,DI = 0.2)were carried out.The pressure ratio and peak efficiency of the compressor decrease with the increase of distortion.The peak efficiency at DI = 0.2 is 0.77 % lower than that at DI = 0.1and 8.42 % lower than that at uniform inlet.When DI = 0.2,the pressure ratio of the peak efficiency point decreases by 1.73 % compared with that when DI = 0.1.The increase of distortion intensity will lead to the increase of relative Mach number,total pressure loss,entropy loss and the expansion of range.Different distortions will lead to certain changes in leaf surface pressure.4 、 The numerical simulation and comparative analysis of the inlet total pressure distortion at three different distortion positions(adjacent area,interval of 60°,interval of120°)were carried out.the influence of distortion position on compressor pressure ratio and efficiency is small;The stability margin increased with the increase of interval,which were11.26 %,12.41 % and 16.53 %,respectively.The total pressure loss and entropy loss also decrease with the increase of the interval position of distortion region. |
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