自摆角式径向柱塞泵配流冲击及影响因素研究

发布时间：2018-06-23 20:52

本文选题：径向柱塞泵 + 配流轴　；参考：《兰州理工大学》2017年硕士论文

【摘要】：高压径向柱塞泵中,配流轴上减振槽的包角角度和截面尺寸对泵的流量脉动起重要作用,因此研究配流轴结构对配流冲击和流量脉动的影响,是提高径向柱塞泵寿命、改善其性能指标的重要途径。在考虑油液压缩性和预升压区减振槽油液倒灌的基础上,根据轴配流式径向柱塞泵的工作机理,以XDP1000自摆角式轴配流高压(42MPa)径向柱塞泵配流副的减振槽结构为研究对象,建立径向柱塞泵在预升压区柱塞腔油液压力随转子转角变化的微分方程和泵出口理论瞬时流量的数学模型,分析三角形减振槽的最大截面边长及包角角度对配流冲击和流量均匀性的影响。建立柱塞泵配流流道的三维模型,根据柱塞的运动形式分析获得柱塞相对于转子的径向速度表达式,并对速度表达式进行速度分解;考虑液压油的可压缩性条件下,编写柱塞相对于转子做伸缩运动的UDF程序;运用CFD动网格技术,对柱塞的刚体运动和柱塞壁面的变形进行定义;在Fluent求解器中进行非定常可压缩流动的流场模拟计算,与数学模型下的分析结果相互比较;分析流场中压力、速度矢量分布,得到泵的流量曲线,并计算流量脉动率。总结数学模型和CFD流场仿真模型的分析结果,得到以下结论:(1)柱塞在预升压区存在不排油现象,以及减振槽由于倒灌而引入柱塞腔的流量是高压径向柱塞泵形成流量脉动的两个重要因素。在考虑油液压缩性与减振槽倒灌流量的情况下,径向柱塞泵的流量脉动率要大于原瞬时理论流量数学模型下得到的脉动率。(2)三角形减振槽截面边长增大,预升压时间相应缩短,但会增大柱塞泵的流量脉动率;增大减振槽包角角度能够减小泵的流量脉动率,但在预升压区出现油液压力升高不到排油压力的现象;柱塞腔油液压力需要满足在预升压区达到排油压力、压力梯度小的条件,否则会形成配流冲击,产生振动和噪声。(3)减振槽的结构参数同时影响柱塞腔油液的升压过程和柱塞泵的流量均匀性:三角形减振槽截面边长取7.9mm、包角取14°时具有较小的压力梯度和脉动率;减振槽包角相同时,半圆形减振槽相比三角形减振槽具有更小的结构尺寸和流量脉动率。(4)CFD模型的结果表明:柱塞泵出口油液压力介于5MPa与42MPa之间时,预升压区均存在油液的倒灌现象,泄压区均存在高压油的回流现象;CFD流场仿真模型下得到的流量脉动率与数学模型的结果相差3%,CFD模型与数学模型得到相互印证。
[Abstract]:In the high pressure radial piston pump, the angle and section size of the damping groove on the damper shaft play an important role in the flow pulsation of the pump. Therefore, it is an important way to improve the life of the radial piston pump and improve its performance index by studying the influence of the structure of the flow shaft on the flow shock and the flow pulsation. On the basis of the liquid inverted irrigation, according to the working mechanism of the axial flow radial piston pump, the differential equation of the oil pressure with the rotor angle in the plunger cavity of the radial piston pump in the pre boosted zone and the instantaneous flow rate of the pump outlet are established by using the vibration damping groove structure of the XDP1000 self pendulum axial piston pump (42MPa) radial piston pump. The mathematical model is used to analyze the influence of the maximum section length and angle of the triangle damper on the flow impact and the flow uniformity. The three-dimensional model of the flow passage of the plunger pump is established. The radial velocity expression of the piston relative to the rotor is obtained according to the movement form of the plunger, and the velocity expression is decomposed, and the hydraulic oil is considered. Under the compressibility condition, the UDF program of the plunger relative to the rotor is written, and the CFD dynamic grid technique is used to define the rigid body movement of the plunger and the deformation of the plunger wall. The flow field simulation of the unsteady compressible flow in the Fluent solver is compared with the analysis results under the mathematical model, and the flow field is analyzed. The flow curve of the pump is obtained and the flow pulsation rate is calculated. The results of the mathematical model and the simulation model of the CFD flow field are summed up. The following conclusions are obtained: (1) there is no oil discharge in the pre lift area and the flow rate of the plunger cavity is introduced into the plunger cavity due to the inversion of the plunger, and the flow pulsation is formed by the high-pressure radial piston pump. Two important factors. In the case of oil compressibility and the flow rate of the damper trough, the flow pulsation of the radial piston pump is higher than that of the original instantaneous theoretical flow mathematical model. (2) the length of the section of the triangular vibration reduction slot increases and the pre lift time is shortened, but it will increase the flow pulsation rate of the plunger pump; increase and decrease the flow rate of the plunger pump. The angle of the slot angle can reduce the flow pulsation rate of the pump, but the oil pressure rise in the pre lift area is not up to the oil discharge pressure; the hydraulic pressure of the plunger cavity needs to meet the condition that the oil pressure and the pressure gradient are small in the pre pressurizing area, otherwise the distribution impact, the production vibration and the noise will be formed. (3) the structural parameters of the vibration damping tank are simultaneously at the same time The rising pressure process of the plunger cavity and the uniformity of the flow rate of the plunger pump are: the length of the section of the triangle damping groove is 7.9MM, the pressure gradient and the pulsation rate are smaller when the angle of the package is 14 degrees. When the angle of the vibration damper is the same, the semi-circular vibration damper has smaller structure size and flow pulsation than the triangle damper. (4) the result table of the model of (4) Ming: when the pressure of the outlet of the plunger pump is between 5MPa and 42MPa, the flow of oil is inverted in the pre pressurized zone, and the reflux phenomenon of high pressure oil exists in the pressure relief area. The flow pulsation rate obtained under the simulation model of the CFD flow field is 3%, and the CFD model and the mathematical model are mutually corroborated.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH137.51

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