| Centrifugal compressor has the characteristics of small size,simple and compact structure,single stage high pressure ratio,which is widely used in turbocharger,small gas turbine and other technology fields.Due to the high speed of the small centrifugal compressor,the internal flow of the compressor is complicated under the complicated conditions of variable flow,multi loads and variable speed.It is a hot issue for the compressor optimization design to pursue the high performance of the compressor under the complicated conditions.The experiential method and trial and error method are of low efficiency,long cycle and high cost for the design of centrifugal compressor,which can not meet the actual complex operation conditions.To find a fast and efficient optimization strategy that can comprehensively consider complex operation conditions,taking a small centrifugal compressor as the research object.this paper investigates the multi-mode and multidisciplinary coupling optimization and uncertainty optimization of the centrifugal compressor,based on the Latin hypercube test design,the Kriging agent model and the NSGA-II method,which is of great significance to improve the performance and life of the compressor.The main contents of this paper are as follows:1.The CFD numerical calculation model of centrifugal compressor impeller was established.The internal flow analysis of LSCC low speed centrifugal impeller and Krain high speed centrifugal impeller was carried out.The calculation results were compared with the experimental data to verify the applicability of the numerical calculation method.2.The influence of impeller geometry parameters such as inlet blade angle,outlet blade angle,tip clearance and impeller angle on compressor aerodynamic performance was studied.Based on the optimization of the Latin hypercube test design,the Kriging agent model and the multi-objective genetic algorithm,the centrifugal compressor was optimized in multiple conditions.The results show that the efficiency of the impeller is increased by 3.52%,the pressure ratio is increased by 5.62%,the efficiency is increased by 3.99%under the design flow,the pressure ratio is increased by 6.43%,and the range of work is widened,variable flow condition optimization can better meet the performance requirements under different working conditions.3.A fluid solid coupling analysis model of centrifugal compressor was established.Considering the effect of aerodynamic load and centrifugal load on the deformation and stress of compressor blades,the sensitivity analysis of the geometric parameters of inlet blade angle,exit blade angle,blade tip clearance and blade package angle to the deformation and stress of compressor blades was studied.The multi-disciplinary coupling optimization of centrifugal compressor impeller was carried out.The results show that the mean value of the impeller pressure ratio is increased by 7.49%,the efficiency is increased by 6.82%,the total deformation of the blade is reduced by 20.4%,and the stable working range is widened..After the aerodynamic structure coupling optimization,the blade geometry is closer to the design blade geometry under actual working conditions,so that the impeller performance and design performance are consistent under actual conditions.4.The two order non embedded probability distribution point method was used to analyze the performance of the compressor,and the influence degree of the uncertainty of the impeller speed fluctuation on the pressure ratio was studied,and an uncertain optimization of the impeller was excuted.The results show that the average pressure ratio of the impeller is increased by 0.81%,the efficiency is increased by about 4.49%,the variance of pressure ratio is reduced by 21.29%,and the performance of the compressor is more stable after the optimization. |
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