Design And Performance Optimization Of Multi-stage Axial Compressor

In this dissertation,the research process begins with the aerodynamic designing of a multistage axial compressor using a design system which was created with the designing tools that the author have.In this design system,it not only have the traditional 1D preliminary、S2 through flow calculation、3D blade modeling and 3D CFD validation but also introduced an iteration process between the 3D CFD validation and S2 through flow calculation process which use the CFD results to amend the efficiency and loss coefficient given in S2 through flow calculation.This design system perfectly overcomed the drawback along with the fact that the S2 through flow calculation program we have do not have lose model and the blade designed by this design system have taken the effect of viscous flow around the end wall area into account.The 8-stage compressor was design with the help of the design system mentioned before,and the evaluation of the compressor performance was conducted.From the evaluation process,we can find that the main parameters in the compressor are distributed reasonably among each stage and the flow angle matches perfectly.At the off-design condition the performance of the compressor is mainly affected by the performance deterioration within the last 3 stages.After the aerodynamic design of the 8-stage axial compressor,the rotor of 1^st stage was chosen to be the study object of non-axisymmetric end wall optimization designing.During the optimization process,the efficiency at both the max efficiency point and design point were chosen to form the object function,in order to make sure that the change of flow rate will not affect the final optimization result.After the comparison between the flow field of the optimized rotor and datum rotor,we find that the non-axisymmetric end wall can not only affect the flow pattern near the end wall by improve the static pressure distribution and the aerodynamic load on the blade airfoil near the end wall region,it can also improve the efficiency along the entire rotor span by remove the reverse flow area and force the mass flow rate to redistribute along the rotor.Although the positive impact of the non-axisymmetric will be impaired by the positive attack angle under the low mass flow rate condition,the optimized rotor still can prevent the formation of reverse flow area.Finally,in order to improve the off-design performance of the compressor,a VGV/VSV turning schedule optimize design platform was built base on HARIKA algorithm.The turning method is to set the turning angle of the 1^st VSV as a reference turning angle and the VGV/VSV of other stages will rotate a specific angle by the reference angle multiply by a constant value which will be determined during the optimization process for each VGV/VSV.The study on the sensitivity of each optimization parameter on the object function and effect of different optimization object was conducted using this optimization platform.The finally VGV/VSV turning schedule was obtained and validated by 3D CFD calculation,the feasibility of this optimization design platform was demonstrated.