一种潮流能直驱式反渗透海水淡化低转速柱塞泵

A Low Speed Piston Pump Directly Driven by Tidal Current Energy for Reverse Osmosis Desalination

针对潮流能直驱式反渗透海水淡化系统中,海水液压泵与水轮机转速不配比问题,提出了一种低转速、高容积效率的动外壳式多作用径向柱塞泵方案。该泵由动外壳、缸体、配流阀、柱塞组件、液体弹簧、管道轴和调压装置等组成。工作时,潮流能水轮机直接驱动外壳,多排错位轴对称的柱塞组件在液体弹簧的作用下紧贴外壳内壁,沿内壁多作用曲线相对缸体孔做往复运动,通过配流阀完成吸压海水。该泵利用单转多次作用方式,增加柱塞运动频率与速度,补偿低转速下因高压差产生的泄漏;利用动外壳式代替动缸体式或动斜盘式,将泵直接置于水轮机内,简化了系统结构;采用分组轴对称布置柱塞,消除了径向不平衡力;采用液体弹簧复位,使得复位迅速,安全可靠。仿真结果表明:该泵排量为202.9 mL/r,额定转速为50 r/min,额定压力为8 MPa;在额定工况下,当柱塞副单边间隙为10μm时,输出流量约为9.8 L/min,容积效率为96.6%,流量脉动为1.92%;配流阀启闭动作协调,单阀最大配流量为2.0 L/min;在保证容积效率下,额定转速降低至已有水液压轴向柱塞泵产品的5%左右。该柱塞泵可应用于以潮流能直驱的反渗透海水淡化系统、发电系统等核心能量转换设备。

A multiple-action radial piston pump scheme with a revolving outer ring featuring low speed and high volumetric efficiency is proposed to solve the problem of rotating speeds mismatch between the seawater hydraulic pump and the hydro-turbine in the reverse osmosis desalination system driven by tidal current energy.The pump is composed of a moving shell,a cylinder,a distributing valve,a plunger component,a liquid spring,a pipeline shaft,and a pressure regulator,etc.When the pump is working,the tidal current energy hydro-turbine drives the shell directly and the multi-row misaligned axisymmetric plunger component is closely attached to the inner wall of the shell under the action of the liquid spring,moves reciprocally along the multi-action curve of the inner wall relative to the cylinder hole,and completes seawater suction and compression through the distribution valve.The pump realizes multiple actions within single rotation to raise the frequency and velocity of the piston and to reduce its leakage caused by highly differential pressure at a lower speed.By using the moving shell mode instead of the moving cylinder or the moving swash plate mode,the pump is directly placed in the hydro-turbine,which simplifies the structure of the device as well as the whole working system.Moreover,the piston uses a grouped axisymmetric arrangement to eliminate the radial force and adopts the liquid spring to ensure rapid,safe and reliable reset.Numerical results show that:the displacement of the design is 202.9 mL/r,rated rotating speed is 50 r/min,rated pressure is 8 MPa;Under the rated condition and when the clearance of the plunger pair is 10μm,the output flow rate of the pump is about 9.8 L/min,the volume efficiency is 96.6%,and the flow pulsation is 1.92%;The opening and closing of the distributing valve are well coordinated,and the maximum flow rate of single valve is 2.0 L/min;The rated rotating speed is reduced to 5%of that of the existing water hydraulic axial piton pump with a similar volumetric efficiency.The radial piston pump provides a basis for the research and development of key energy conversion equipment such as reverse osmosis desalination systems and power generation systems that are directly driven by tidal current energy.