| Compared with traditional energy,hydrogen has the advantages of environmental protection and economy.Hydrogen energy industry has become one of the key industries in the world.At present,most compressors used to compress hydrogen are reciprocating compressors,which have a small flow rate compared with centrifugal compressors.In the long distance pipeline transportation of hydrogen,the traditional reciprocating compressor obviously can not meet the demand,and the centrifugal compressor has the advantages of large compression flow,long operation cycle,small footprint,low maintenance costs,more suitable for the long distance pipeline transportation of hydrogen.Centrifugal compressor is an important equipment for the development of hydrogen energy,so it is of great significance to further study it.Based on the one-dimensional design theory of the traditional centrifugal compressor with working medium,the pneumatic design method of the hydrogen centrifugal compressor with working medium is introduced in detail,and the optimal design program of the hydrogen centrifugal compressor is developed independently.Four parameters that have great influence on compressor efficiency are selected as optimization variables.BP neural network combined with genetic algorithm is used to carry out single objective optimization of isentropic efficiency of hydrogen centrifugal compressor,and the optimization parameters are obtained.Then,based on the cross-section parameters of the impeller with one-dimensional optimization design,a three-dimensional model of the compressor was established,and NUMECA software was used for numerical simulation calculation,and the design condition,variable condition performance and three-dimensional flow field analysis of the compressor were analyzed.The results show that the efficiency of the optimized hydrogen centrifugal compressor is obviously improved.Through the analysis of the internal flow field of the compressor,it is verified that the hydrogen centrifugal compressor has good performance.In order to explore the internal flow law of the hydrogen centrifugal compressor,this paper takes the first-stage hydrogen centrifugal compressor as an example to conduct numerical simulation of the hydrogen centrifugal compressor by changing the length of the shitter blade,the circumferential position and the size of the blade tip clearance,and analyzes the internal flow field of the hydrogen centrifugal compressor in detail.The results show that the performance of the hydrogen centrifugal compressor can be improved by applying the shunt blade in the impeller.When the length coefficient of the shunt blade is 0.8 and the circumferential position coefficient is 0.5,the performance of the hydrogen centrifugal compressor is the best.With the increase of tip clearance of centrifugal compressor impeller,partial leakage of air flow is generated at the tip.The larger the tip clearance is,the larger the tip leakage will be,which leads to the reduction of compressor performance.Because the working medium of compression is hydrogen,hydrogen emittance should be considered in the design of hydrogen centrifugal compressor.According to the standard requirements of "axial flow,centrifugal compressor and expander compressor for petroleum,chemical and gas industry"(API 617),when the hydrogen content is greater than 90%,the yield strength of impeller material cannot be greater than 827 MPa.So in the end of this paper,the impeller strength analysis.By referring to relevant literature,7075-T6 aluminum alloy with anti-hydrogen embrittleability is selected as the compressor material.Through the strength analysis of the centrifugal compressor impeller,it can be concluded that the maximum stress of the impeller appears at the chamfer of the shaft hole on the back of the hub,and its maximum stress is 328.26 MPa,which is less than the yield strength of the material,and the maximum deformation at the tip is less than the tip clearance,so the strength of the impeller meets the requirements. |
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