Study On Coupling Characteristics Of Axial Piston Pump And Energy Recovery Machine For Seawater Desalination

At present,the global fresh water resources are in short supply,and the reverse osmosis seawater desalination technology is currently the mainstream technology with high marketization and wide application prospect.Energy recovery device is one of the three key components of reverse osmosis seawater desalination system,compared with foreign advanced technology,energy recovery has been the main bottleneck restricting the development of seawater desalination device in China.This paper takes the axial piston pump and energy recovery machine as the research object,analyzes the coupling characteristics and influencing factors in the operation process through theoretical research,simulation analysis and experimental verification,reveals the influence law of key parameters,which can provide a theoretical reference for the optimal design of axial piston pump and energy recovery machine.The research in this paper is based on the National Key Research and Development Plan "Research on Key Technology and Product Development of Pump and Energy Recovery Machine for Seawater Desalination(2017YFC0404201)",the main research work and achievements are as follows:(1)The mathematical modeling and simulation analysis of the axial motion of single piston,the flow and pressure in single piston chamber,the leakage from main friction pairs,the flow and pressure of axial piston pump and axial piston motor,and the torque of axial piston pump and energy recovery machine were carried out,and the detailed mathematical models of the flow area of axial piston pump and axial piston motor were established.The simulation results of the leakage from three main friction pairs show that the leakage from slipper pair is the most serious,followed by the leakage from port pair,and the leakage from piston pair is the least.The outlet flow and pressure of axial piston pump,the inlet flow of axial piston motor show 9 ripples in one rotation cycle,and the inlet pressure ripple of axial piston motor changes slightly.The torque simulation results of axial piston pump and energy recovery machine show that the actual output torque of axial piston motor accounts for 57.68% of the actual input torque of axial piston pump.(2)The coupling characteristics of axial piston pump and energy recovery machine under different structural parameters were simulated and analyzed,the simulation results show that the outlet flow and flow ripple amplitude of axial piston pump,the actual input torque and torque ripple amplitude of axial piston pump,the actual output torque and torque ripple amplitude of electric motor all increase significantly with swashplate angle of axial piston pump increasing.The inlet flow and flow ripple amplitude of axial piston motor,the actual output torque and torque ripple amplitude of axial piston motor increase gradually,the actual output torque of electric motor decreases while torque ripple amplitude increases slightly with swashplate angle of axial piston motor increasing.The outlet flow and flow ripple amplitude of axial piston pump decrease significantly,while the inlet flow and flow ripple amplitude of axial piston motor increase gradually with clearances of piston pair and slipper pair increasing.The outlet flow and flow ripple amplitude of axial piston pump decrease gradually,the inlet flow of axial piston motor increases while flow ripple amplitude changes slightly with clearance of port pair increasing.The flow and pressure in piston chamber of axial piston pump are affected to varying degrees by changing the length,width and depth of U-type groove.(3)The coupling characteristics of axial piston pump and energy recovery machine under different operating conditions were simulated and analyzed,the simulation results show that the outlet flow and flow ripple amplitude of axial piston pump,the actual input torque and torque ripple amplitude of axial piston pump,the inlet flow and flow ripple amplitude of axial piston motor,the actual output torque and torque ripple amplitude of electric motor all increase,the actual output torque of axial piston motor decreases while torque ripple amplitude increases slightly with speed of electric motor increasing.The actual input torque and torque ripple amplitude of axial piston pump,the actual output torque and torque ripple amplitude of electric motor decrease gradually with inlet pressure of axial piston pump increasing.The outlet flow of axial piston pump decreases slightly while flow ripple amplitude increases slightly,the actual input torque and torque ripple amplitude of axial piston pump,the inlet flow and flow ripple amplitude of axial piston motor,the actual output torque and torque ripple amplitude of axial piston motor,the actual output torque and torque ripple amplitude of electric motor all increase gradually with outlet pressure of axial piston pump increasing.The actual output torque of axial piston motor decreases,while the actual output torque of electric motor increases,and the torque ripple amplitude of both changes slightly with outlet pressure of axial piston motor increasing.(4)The performance experiments of axial piston pump,axial piston pump and energy recovery machine were carried out respectively,the experimental results show that the outlet flow and volumetric efficiency of axial piston pump increase gradually with speed of electric motor increasing.The actual input torque of axial piston pump decreases gradually,while the mechanical efficiency has a minimal reduction with inlet pressure of axial piston pump increasing.The outlet flow and volumetric efficiency of axial piston pump decrease gradually,while the actual input torque and mechanical efficiency of axial piston pump increase significantly with outlet pressure of axial piston pump increasing.The experimental results of axial piston pump,axial piston pump and energy recovery machine are basically consistent with the simulation values.