【作者】 翟江；

【导师】 周华；

【作者基本信息】 浙江大学 ， 机械电子工程， 2012， 博士

【摘要】 高压泵是反渗透海水淡化工程中的关键元件。与目前广泛使用的多级离心泵、往复泵相比,基于水液压技术的全水润滑轴向柱塞结构的海水淡化高压泵具有效率高、噪音低、体积小、易维护等优点,适合在中小型反渗透海水淡化系统中使用。本文以研制中小型反渗透海水淡化系统中使用的高压轴向柱塞泵为目标,开展泵的特性及其关键技术研究,为水介质轴向柱塞机械的研究和开发提供参考。本文考虑了泵在工作过程中因海水的可压缩性、高饱和蒸汽压诱发空化等引起的弹性模量、密度、动力粘度等流体属性的变化,建立了泵柱塞腔压力、泵柱塞腔内部空化、泵柱塞腔吸排水流量、泵进出口流量、泵关键摩擦副内泄漏流量和泵出口压力的动态模型。与不考虑流体属性变化的模型相比,该模型避免了仿真过程中绝对压力出现负值等现象,并能对柱塞腔内的空化、泵进口压力过低造成的吸空进行估计。根据海水淡化高压轴向柱塞泵的主要工作参数,通过对低粘度海水润滑下完全平衡型滑靴副缝隙流动的流态分析,得到了完全平衡型滑靴副中固定阻尼区域一般处于湍流状态,可变阻尼一般处于层流状态的结论,在此基础上进行了完全平衡型滑靴副的设计。考虑到滑靴体工程塑料覆盖层在高压水流下的微小变形对流动区域压力场的影响,提出了基于流固耦合数值分析的修正方法。在国内成功研制出适用于中小型反渗透海水淡化工程的高压轴向柱塞泵,该泵采用全水润滑端面配流结构,额定工作压力为8MPa,额定转速为1500rpm。性能试验结果表明该泵在额定工况下输出的实际流量超过110L·min-1,总效率超过80%。在反渗透海水淡化系统中的实际应用表明该泵性能稳定、可靠性高,能够在中小型海水淡化工程中替代同类进口产品。第一章介绍了反渗透海水淡化工程中高压泵技术的现状,分析了轴向柱塞结构高压泵的优势,指出了本文的研究目的及意义,介绍了本文的主要研究内容。第二章建立了海水主要流体属性随压力变化的模型,通过与轴向柱塞泵压力流量特性方程组相结合,得到了基于海水流体属性的海水淡化高压轴向柱塞泵压力流量特性模型,通过对模型的数值计算分析了泵的空化、压力、流量、泄漏和效率等特性。第三章建立了海水淡化高压轴向柱塞泵工作过程的动态CFD模型,对泵内部的空化流动进行了数值模拟,在不同的泵入口压力条件下,获得了泵内空化发生的位置和作用时间、柱塞腔吸排海水流量、泵出口截面的质量流量和平均压力脉动等特性。第四章讨论了海水润滑滑靴副的设计方法,推导了海水润滑完全平衡型滑靴副的设计计算公式。对采用了低弹性模量工程塑料的完全平衡型滑靴副的结构场和流场进行了流固耦合分析,讨论了微小弹性变形对其静压支承性能的影响。第五章分析了海水淡化高压轴向柱塞泵主要零件的动力学特性,获得了泵关键摩擦副的动态pv值数据。建立了海水淡化高压轴向柱塞泵的虚拟样机,综合分析了泵主要零件的动力学特性、泵的压力流量特性,获得了主要零件的动态等效应力和变形位移等数据。第六章在水润滑条件下对多种耐蚀金属与聚醚醚酮配对进行了摩擦学试验,获得了相应的摩擦磨损数据,分析了摩擦表面的微观形貌,为海水淡化高压轴向柱塞泵关键摩擦副配对材料的选择提供了参考。第七章介绍了海水淡化高压轴向柱塞泵样机的主要加工工艺过程,对加工完成的样机进行了性能试验,完成性能试验的样机进行了实际应用。第八章对本文的研究工作进行了总结,对进一步的研究提出了展望。更多还原

【Abstract】 High pressure pump is one of the most important components in Sea Water Reverse Osmosis (SWRO) desalination engineering. Compared with multi-stage centrifugal pump and reciprocating pump which are widely used in SWRO projects, high-pressure axial piston pump based on water hydraulic technology has many advantages, such as high efficiency, small size, low noise and full water lubricated, and it is suitable to be used in small and medium scale SWRO systems. In order to develop the axial piston pump, this dissertation focuses on its main characteristics and key technology.In this dissertation, as the cavitation caused by high vapour pressure and slightly compressibility of seawater, the variable fluid properties such as elastic modulus, mass density and viscosity were considered in pressure and flow model of the high pressure axial piston pump for SWRO. Compared with the model without considering variable fluid properties, the new model avoids the negative pressure value in simulation process and can predict cavitation and sucked empty of the pump to a certain extent. Base on the main operating parameters of the pump, the gap flow pattern of the hydrostatic bearing slipper pair lubricated by seawater was analyzed. It was concluded that the flow regime of the variable damping is laminar but the fixed damping is turbulent. The corresponding design and calculation formulas were derived. Because the micro deformation of slipper body can influent the pressure field of the flow regime, the correction and compensation methods based on fluid-solid coupling numerical analysis were presented. The prototype of high pressure axial piston pump for SWRO was successfully developed in the domestic. This pump is directly lubricated by seawater and uses valveplate as it distributor. The rated operating pressure of the pump is8MPa, and the rated rotation speed is1500rpm. From the results of performance test at rated operating condition, the actual flow rate of the pump is over110L·min-1and the total efficiency is over80%. The practical application of the pump in SWRO projects shows that the pump has stable performance, high reliability, and can replace similar imported products in the small and medium scale SWRO systems.In Chapter1, current status of high pressure pumps in SWRO projects were described. The advantages of high pressure axial piston pump were analyzed. The main research objects and academic significances of this dissertation were pointed out. The main contents of this dissertation were introduced.In Chapter2, the main fluid properties of seawater varying with pressure were modeled, and the pressure and flow model of the axial piston pump for SWRO was built by the combination of fluid properties models and pressure-flow equations of axial piston pump. The dynamic pressure, flow, leakage, cavitation and efficiency of the pump were analyzed by the numerical calculation of this model.In Chapter3, the dynamic CFD model of the pump at working was established, and the cavitation flow in the pump was numerically simulated. At different inlet pressures, the dynamical cavitation position and duration, the mass flow rate of single cylinder chamber, the oulet mass flow and pressure ripple rate were analyzed.In Chapter4, the design method of slipper pair lubricated by seawater was discussed, the calculation formulas of hydrostatic bearing slipper pair were derived. The structure field and flow field of hydrostatic bearing slipper pair lubricated by seawater were analyzed by fluid-solid coupling numerical method. The influence of micro deformation of slipper body to hydrostatic supporting ablity was analyzed.In Chapter5, the dynamic mechanical characteristics of main parts of the pump were analyzed. The dynamic pv values of key tribo-pairs of the pump were acquired. The virtual prototype of the pump was built, and comprehensive analysis of the dynamic mechanical characteristics, stress and deformation displacement of the main parts, pressure and flow of the pump were analyzed.In Chapter6, tribology tests under water lubrication of variety corrosion resistant metals against composite PEEK materials were completed. Corresponding friction and wear data, morphology of friction surfaces were presented. This test is a basis for materials selection of the key tribo-pairs for the pump.In Chapter7, the main machining processes of the pump’s prototype were introduced. The performance test of the pump was carried out. The pump, which was completed performance test, was used as high pressure pump at a SWRO experimental system. The pump was also used at a SWRO sytem in a desalination plant at a certain island as demonstration application.In Chapter8, the research work of this dissertation was summarized, and some advices on further research work were presented.更多还原