Design And Research Of High Speed Centrifugal Compressor For Hydrogen Fuel Cell Vehicle

With the increasing degree of environmental pollution and the petroleum shortage,the research and development of new energy vehicles became extremely urgent.Hydrogen fuel cell has been gradually considered as one of the most promising substitute resources to empower vehicles for its easy accessibility and zero emission of polluting reaction products.Due to the space and weight limitations on vehicles and high performance requirements,centrifugal air compressor has gradually become the mainstream type when designing a hydrogen fuel cell.In this paper,a high-speed centrifugal compressor with air bearings was designed for hydrogen fuel cell vehicle,and the following works were done:1)Three-dimensional flow field structure of both compressor and expansion sections on high-speed centrifugal compressor were designed with specific speed method and specific enthalpy drop method.Their characteristic performance curves were then analyzed by CFD software FLUENT.The results showed that the performance of this compressor can meet the requirements to be used on hydrogen fuel cell,and the power consumption will be effectively reduced by the gas recovery of its expansion end.2)Based on the stress analysis,the maximum stress and maximum deformation of the compressor impeller were studied and its working safety was proved in this way.LS-DYNA software was used to simulate its containment capacity,and the process of impact was analyzed with energy and acceleration change rules.The result proved that the volute could completely contain impeller fragments and ensured the working safety of high-speed centrifugal compressor.3)Based on dynamic grid method and linear displacement increment method,a study was carried out to analyze the influence on the dynamic characteristics of air radial bearing with the change of its structure.On account of this analysis,the bearing-rotor system shaft of centrifugal compressor was designed and validated by modal analysis,unbalance response analysis and impact response analysis.4)An experimental platform was set up to get the working performance curve of the compressor.With its comparison to the simulation results,the method of the compressor’s performance simulation was proved to be reliable.The experimental critical speed of the air bearing-rotor system was also compared with the simulation results,which proved the accuracy of the simulation results of the air bearings’ dynamic performances.As thus,the design of the air bearing-rotor system was verified.After the process of structural design,numerical simulation and experimental research,the design of high-speed centrifugal air compressor for hydrogen fuel cell vehicle has been completed,and the factors affecting dynamic performances of air bearing were studied.All of the researches provided important reference for future studies.