| Energy storage technology can facilitate the large-scale development of renewable energy and effectively solve the energy and environmental problems in our country.Compressed air energy storage(CAES)has the advantages of large storage capacity,long performance life,and it is not restricted by geographical environment,which has great development prospects.The compressor is the core equipment in the CAES system,and its performance directly determine the overall system efficiency and energy storage economy.Different from the common industrial compressors that usually operate near the design conditions,the compressors in the energy storage system need to have the ability to operate at high load and high efficiency over a wide range of flow rate and pressure ratio.Therefore,it is one of the key technologies to improve the compressors' capability of operating under off-design conditions with high efficiency and provide a safe and stable operation control scheme for the compressor in the CAES system.The typical stage of the multistage geared centrifugal compressor in a large-scale CAES system is selected as the research object and adjustable inlet guide vanes(AIGVs)and adjustable vaned diffuser(AVD)are taken as two adjustment technologies for off-design conditions in this paper.An in-depth research on the off-design condition characteristics of the centrifugal compressor is carried out through numerical and experimental methods.Finally,the optimal regulation strategies are found for the compressor operation in the CAES system.The main research contents and conclusions are as follows:1.According to the design parameters of the typical centrifugal impeller,the one-dimensional design program is compiled to obtain the one-dimensional aerodynamic parameters of the variable geometry component blades first.Then the three-dimensional blades optimization design is fulfilled based on the neural network and genetic optimization algorithm.Finally,the adjustment mechanism design is accomplished.A set of design system for highly efficient matching of variable geometry components and centrifugal impellers has been established.2.Based on the high-power multi-stage intercooling comprehensive experimental platform of the CAES compressor,the overall stage performance test system and the internal flow field measurement system are designed and built.The off-design condition performance curves of the centrifugal compressor under different inlet guide vane stagger angles and different vaned diffuser stagger angles are obtained.The flow field change laws of the inlet guide vane outlet and the impeller outlet are also obtained.These research results reveal some important flow phenomena of the centrifugal compressor during off-design condition adjustment.3.The complete calculation model of the centrifugal compressor is established.According to the full three-dimensional steady flow numerical calculation,a comprehensive analysis of the performance change laws and internal flow field distribution laws of the centrifugal compressor under different inlet guide vane stagger angles and different vaned diffuser adjustment angles is done.The research and analysis of the centrifugal compressor reveals the mechanism of energy loss when the centrifugal compressor operates under off-design conditions through adjustment.4.The compressor in the CAES system has the characteristics of operating under off-design conditions with high efficiency.In order to solve the optimization problem of multi-dimensional spatial variables that adjustment angle changes in the process of combined adjustment of AIGVs and AVD,the Kriging interpolation model and Nelder-Mead optimization method are introduced to obtain the high-efficiency off-design conditions regulation method of the centrifugal compressor.The results show that the combined adjustment of AIGVs and AVD enables an increase in pressure ratio range by 232.5%,the maximum efficiency is increased by 1.2%,and the average efficiency is increased by 2.8%compared with the condition that adjustment is absent. |
PDF Full Text Request