Research On The Adjustment Of Variable Inlet Guide Vane Of Axial Compressor Under Off-design Condition

Compressor is one of the core parts of gas turbine development.The adjustable guide vanes of compressor can increase surge margin,improve efficiency of off-design working conditions and improve the starting and acceleration of gas turbine.Therefore,in-depth research on regulating laws of guide vane of compressor has both theoretical and practical value.In this paper,the regulation law of a 2.5 stage transonic axial compressor with adjustable guide vanes under different back pressure at 0.6n working conditions were studied by numerical simulation and experimental methods,and the flow field with different guide vanes installation angles was numerically simulated and experimentally measured.Because the internal flow of a compressor is three-dimensional,viscous and unsteady in nature,the unsteady characteristics of the compressor are numerically simulated by using the nonlinear harmonic method.The main contents are as follows:1.By commercial software NUMECA of 112000Pa,110000Pa and 108000Pa respectively under the back pressure of guide vane and exploration on the regulation law,respectively,find the maximum efficiency point of the guide blade installation Angle of+4°,0° and 8°.And through the experimental means to verify.2.The performance characteristic curves of the three guide vane installation angles were obtained by numerical simulation method,and compared with the experimental measurement results,the performance curve trends of pressure and efficiency were basically consistent with the experimental values,and the error was within a certain range of requirements,which verified the reliability of the numerical simulation method.The surge margin of different installation Angle is analyzed.3.The internal flow field of the compressor with three installation angles was analyzed in detail,including the limit flow line of suction surface,inlet flow angle,surface static pressure coefficients of different blade heights,the efficiency along the direction of the blade outlet,the relative Mach number,velocity vector and entropy of S1 flow surface.4.Nonlinear harmonic method is used to calculate the unsteady state of the compressor.With the increase of harmonic order,the simulation of unsteady characteristics is more realistic.The 5-order nonlinear harmonic method achieves a good compromise between calculation time and accuracy for 2.5-stage axial compressor,and has a good practical application prospect.5.The nonlinear harmonic method can effectively capture the unsteady characteristics of rotor and stator interference in a compressor.When rotor and stator blades are in different relative positions,the static pressure and isentropic Mach number of different blade heights,and entropy of S1 flow surface change periodically as the rotor sweeps.6.Build and debug the 2.5 stage axial compressor test bench,and introduce the experimental principle,the composition of the test bench and the measurement system.The phase doppler anemometer(PDA)was used to non-contact measure the velocity of the first stage rotor blade inlet and outlet and the second stage rotor blade inlet,and the results were compared with the calculated values and verified each other.