Research On Effect Of Rotor/Stator Interface Approach And Turblence Model On Simulation Of Compressor

With the development of computational fluid dynamics, more and more rotor/stator interface approach and turbulence model is applied to the simulation of turbomachinery. However, different rotor/stator interface approach and turbulence model has a significant influence on the accuracy of the numerical calculation of turbomachinery. With the NASA stage 35 axial compressor as an object of study, the simulation of compressor was carried out with different approaches of data transmission at rotor/stator interface and turbulence models on the basis of choosing appropriate grid density.In order to study the effects of mixing plane approach on the simulation of NASA stage 35 compressor, the new 2d non-reflection of Numeca is compared with conservation coupling by pithwise row and full non-matching mixing plane.Conclusions are as follows:(1) For the prediction of adiabatic efficiency, the result of 2d non-reflection is more closer to the experimental values than that of conservation coupling by pithwise row and full non matching mixing plane. For the prediction of the total pressure ratio,the precision of 2d non reflection is relatively high at near peak efficiency condition,but in the near stall condition it is relatively low.(2) Comparison and analysis of accuracy to stator outlet total pressure, total temperature, relative flow angle and relative Mach number along the radial distribution,the results show that the prediction accuracy of conservation coupling by pithwise row and full non matching mixing plane is consistent, but it is less than that of 2d nonreflection.(3) For the prediction of total pressure and total temperature on the both sides of interface along the radial distribution, the results show that three kinds of mixing plane approach can not guarantee the conservation of total pressure and total temperature, but the change is very small.(4) Comparison and analysis of meridian entropy contours and the entropy of middle section of rotor and stator along the radial distribution, the results show that the entropy change of conservation coupling by pithwise row and full non-matching mixing plane is consistent, but the change of entropy is very small for the mothed of 2dnon-reflection. It indicates that the loss resulted from 2d non reflection is small.(5) Comparison and analysis of relative mach number contours, it was found that the accuracy of the three kinds of mixing plane method is consistent in root and leaf blade section. Meanwhile, the airflow separation on the suction surface of the rotor blade predicted by the conservation coupling by pithwise row is more obvious, and the relative Mach number contours predicted by full non matching mixing plane is more intensive in the downstream stator passage.In order to study the effects of turbulence model on the simulation of NASA stage35 compressor, K-epsilon(Extend Wall Function), K-epsilon(Low Re Yang-Shih), Shear Stress Transport(SST), Baldwin-Lomax, Spalart-Allmaras and EARSM turbulence model are adopted in numerical simulation.(1) Comparison and analysis of mass flow, total pressure ratio and adiabatic efficiency in three common condition, it was found that the prediction accuracy of each model is different in different conditions and the optimal model of NASA stage 35 compressor can not be determined.(2) The results show that the Spalart-Allmaras model and the SST model are relatively good at the calculation of conditions from choke to stall.(3) Comparison and analysis of radial performance parameters in three typical working conditions, which are choke point, peak efficiency point and stall point, the accuracy of SST model is better than Spalart-Allmaras model.(4) Comparison and analysis of relative mach number contours in 90 percent of blade at near stall condition, it was found that the shock wave intensity predicted by Baldwin-Lomax model is strong, but the K-epsilon model is weak. Meanwhile, six kinds of turbulence model in the near the pressure side of rotor and the trailing edge of the rotor and stator appeared in the low energy region, which Baldwin Lomax, SST and spalart allmaras are smaller, K-epsilon model range most widely.(5) Comparison and analysis of the limit line of the rotor suction surface in the near stall condition, a complete separation of the K-epsilon model was made at the top of the leaf. However, the other five models have been separated at the top of the leaf and the flow is soon to be attached.