基于CFD的海水淡化轴向柱塞泵关键技术研究

发布时间：2018-10-22 06:56

【摘要】：作为反渗透海水淡化工程的核心部件之一,高压泵对制水成本、运行维护等有着重要的影响。高压柱塞泵凭借其效率高、体积小、寿命长等优点,适用于中小规模反渗透海水淡化工程来降低能耗。但是,柱塞泵固有的压力和流量脉动产生较大的工作噪声,限制了柱塞泵的运用。国内对于压力和流量脉动控制的研究与国外相比存在一定的差距。因此,对于柱塞泵这两方面脉动的研究有较高的理论和实用价值。对柱塞泵工作原理以及噪声产生机理进行研究,深入分析了柱塞的运动规律、泵体内主要的间隙泄漏,并得出了相应的流量泄漏表达式。通过对不同转角条件下柱塞腔与配流盘间交界面进行分析,推导出了过流面积公式。在此基础上,确定柱塞泵内流体主要为湍流状态,对应的CFD仿真分析时求解模型为标准k-ε模型。然后,建立了柱塞泵CFD仿真分析流体模型,编写了柱塞运动控制UDF程序,并运用CFD分析软件Fluent对模型进行分析。通过CFD仿真分析研究了柱塞数目、斜盘倾角、缸体转速、配流盘结构以及负载压力对柱塞泵出口流量脉动的影响规律,发现:柱塞数奇数时柱塞泵出口流量脉动率明显低于相邻的偶数柱塞时,且随着柱塞数目增多,流量脉动率逐渐降低;柱塞泵斜盘倾角增大或者缸体转速升高,柱塞泵排量增大,出口流量脉动率降低;负载压力增大时,柱塞泵出口流量脉动率也随之升高;在配流盘过渡区域增加阻尼槽后,可以将柱塞泵出口流量脉动率降低60%以上。由于缺乏相关的理论指导,本课题在对柱塞腔内压力脉动进行研究时,参照流量脉动的分析方法,探究了流量脉动影响因素对柱塞腔压力脉动的影响情况。结果显示,柱塞数目奇偶性和配流盘阻尼槽对压力脉动与流量脉动的影响规律一致;柱塞泵转速和负载压力对二者的影响规律相反;斜盘倾角对柱塞腔压力脉动的影响无明显规律性。将以上五因素对柱塞泵出口流量脉动、柱塞腔压力脉动以及排量的影响规律相结合给出了柱塞泵设计时的一些参考意见。在配流盘阻尼槽结构优化时,对吸排水腔配流盘阻尼槽的宽度角和深度角分别进行了研究。研究结果表明:对于吸水区和排水区三角阻尼槽,当宽度角为90°左右,深度角为6°左右时,柱塞腔压力脉动和出口流量脉动最小。在相同的过流面积条件下,三角形阻尼槽的降噪效果好于U形阻尼槽降噪效果。
[Abstract]:As one of the core components of reverse osmosis seawater desalination project, high pressure pump has an important influence on water production cost, operation and maintenance. High pressure piston pump has the advantages of high efficiency, small volume and long life, so it can be used to reduce energy consumption in small and medium scale reverse osmosis seawater desalination project. However, the inherent pressure and flow pulsation of piston pump cause greater noise, which limits the application of piston pump. There is a certain gap between domestic pressure and flow pulsation control. Therefore, the research on the pulsation of piston pump has high theoretical and practical value. The working principle and noise generation mechanism of piston pump are studied. The movement law of plunger, the main clearance leakage in pump body and the corresponding flow leakage expression are obtained. Based on the analysis of the interface between the plunger cavity and the flow distribution disc at different rotation angles, the formula of flow area is derived. On this basis, it is determined that the fluid in the piston pump is mainly turbulent, and the corresponding CFD simulation model is the standard k- 蔚 model. Then, the CFD simulation analysis fluid model of piston pump is established, the UDF program of plunger motion control is written, and the model is analyzed by CFD analysis software Fluent. The effects of plunger number, tilting angle, cylinder speed, disk structure and load pressure on the flow pulsation at the outlet of the piston pump are studied by CFD simulation. It is found that when the plunger number is odd, the flow pulsation rate of the piston pump outlet is obviously lower than that of the adjacent even number plunger, and with the increase of the plunger number, the flow pulsation rate decreases gradually, and the tilting angle of the plunger pump increases or the cylinder speed increases. The flow pulsation rate of the piston pump increases with the increase of load pressure, and the flow pulsation rate of the piston pump can be reduced by more than 60% after the increase of damping tank in the transition region of the distribution disk. Due to the lack of relevant theoretical guidance, in the study of pressure pulsation in the plunger cavity, the influence factors of the flow pulsation on the pressure pulsation of the plunger cavity are explored according to the analysis method of the flow pulsation. The results show that the effect of parity of plunger number and damping slot on pressure pulsation and flow pulsation is consistent, while the effect of piston pump speed and load pressure on them is opposite. The effect of inclined angle on the pressure fluctuation of plunger cavity has no obvious regularity. Combining the above five factors on the flow pulsation at the outlet of the piston pump, the pressure pulsation of the plunger cavity and the influence law of the displacement, some reference suggestions for the design of the piston pump are given. The width angle and depth angle of the damping slot in the suction and drainage cavity were studied respectively when the structure of the damping slot was optimized. The results show that when the width angle is about 90 掳and the depth angle is about 6 掳, the pressure pulsation and outlet flow pulsation of the plunger cavity are minimum. Under the same flow area, the noise reduction effect of triangular damping tank is better than that of U-shaped damping tank.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P747;TH322

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