外啮合斜齿轮高压泵的CFD数值模拟
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摘要
为研究流量脉动系数对外啮合斜齿轮高压泵内部流场的影响,通过理论推导流量脉动系数的计算公式,分析螺旋角对流量脉动系数的影响,并结合计算流体力学(CFD),对外啮合斜齿轮高压泵的流场进行数值模拟,得到高压泵在不同转速、不同径向间隙下的压力脉动和流量特性.结果表明:增大螺旋角会减小流量脉动系数,有利于改善出口流量的品质,降低齿轮泵泄漏;另外,转速和径向间隙在一定范围内增大时,脉动系数逐渐减小,泄漏涡强度也会减小.当转速和径向间隙继续增大时,脉动系数趋于平稳波动;转速增大时,啮合区域的压力变化较大,但是靠近泵腔壁处的齿轮压强变化较小;径向间隙增大时,泄漏流动和泄漏涡强度会降低,在设计中适当增大转速和径向间隙可以改善出口流量品质.研究高压泵内部流场的运动规律和流量脉动特性对于外啮合斜齿高压泵的设计和优化具有一定的参考价值.
In order to study the influence of flow pulsation coefficient on the internal flow field of external helical gear high-pressure pump,the influence of the helix angle on the flow pulsation coefficient was analyzed by the theoretical formula. Combined with computational fluid dynamics( CFD),the numerical experiment of the flow field in the external gear helical gear was carried out,and the influence of different rotational speeds and radial clearances on the pressure pulsation and flow characteristics was analyzed. The results show that the larger helix angle reduces the flow pulsation coefficient,it is good for improving the quality of the outlet flow and reducing the gear pump leakage. Furthermore,when the rotational speed and radial clearance increase within a certain range,the pulsation coefficient decreases and the leakage vortex intensity also decreases. When the rotational speed and radial clearance continue to increase,the pulsation coefficient tends to be stable. When the rotational speed increases,the pressure in the meshing area varies greatly,but the gear pressure near the pump wall changes little. On the other hand,when the radial clearance increases,the leakage flow and leakage vortex intensity will be reduced,the quality of outlet flow will also be improved by increasing the speed and radial clearance. The study of the motion law and flow pulsation characteristics of the internal flow field of the high-pressure pump is of some reference value to the design and optimization of the external helical gear.
In order to study the influence of flow pulsation coefficient on the internal flow field of external helical gear high-pressure pump,the influence of the helix angle on the flow pulsation coefficient was analyzed by the theoretical formula. Combined with computational fluid dynamics( CFD),the numerical experiment of the flow field in the external gear helical gear was carried out,and the influence of different rotational speeds and radial clearances on the pressure pulsation and flow characteristics was analyzed. The results show that the larger helix angle reduces the flow pulsation coefficient,it is good for improving the quality of the outlet flow and reducing the gear pump leakage. Furthermore,when the rotational speed and radial clearance increase within a certain range,the pulsation coefficient decreases and the leakage vortex intensity also decreases. When the rotational speed and radial clearance continue to increase,the pulsation coefficient tends to be stable. When the rotational speed increases,the pressure in the meshing area varies greatly,but the gear pressure near the pump wall changes little. On the other hand,when the radial clearance increases,the leakage flow and leakage vortex intensity will be reduced,the quality of outlet flow will also be improved by increasing the speed and radial clearance. The study of the motion law and flow pulsation characteristics of the internal flow field of the high-pressure pump is of some reference value to the design and optimization of the external helical gear.
引文
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[3]MAITI B. Analysis of flow through pump impellers by finite element method[J]. Applied scientific research,1989,46(2):105-126.
[4]DEVENDRAN R S,VACCA A. A novel design concept for variable delivery flow external gear pumps and motors[J]. International journal of fluid power,2014,15(3):121-137.
[5]SHEN H D,LI Z Q,QI L L,et al. A method for gear fatigue life prediction considering the internal flow field of the gear pump[J]. Mechanical systems and signal processing,2018,99:921-929.
[6]罗先武,张瑶,彭俊奇,等.叶轮进口几何参数对离心泵空化性能的影响[J].清华大学学报(自然科学版),2008,48(5):836-839.LUO Xianwu,ZHANG Yao,PENG Junqi,et al. Effects of impeller inlet geometry on cavitation performance of centrifugal pump[J]. Journal of Tsinghua University(science and technology),2008,48(5):836-839.(in Chinese)
[7]罗先武,刘树红,邵杰,等.微型泵半开式离心叶轮的空化性能[J].清华大学学报(自然科学版),2006,46(8):1451-1454.LUO Xianwu,LIU Shuhong,SHAO Jie,et al. Spification of micro-pump half-open centrifugal impeller[J]. Journal of Tsinghua University(science and technology),2006,46(8):1451-1454.(in Chinese)
[8]张静,史伟东,胡亮,等.斜齿轮泵流量及其流量脉动特性分析[J].液压气动与密封,2016(6):8-12.ZHANG Jing,SHI Weidong,HU Liang,et al. Analysis of flow and its pulsation characteristics of helical gear pump[J]. Hydraulic pneumatic and seal,2016(6):8-12.(in Chinese)
[9]孔繁余,何玉洋,郑德,等.外啮合齿轮泵流量特性影响因素分析[J].排灌机械工程学报,2014,32(2):108-112.KONG Fanyou,HE Yuyang,ZHENG De,et al. Analysis of influencing factors of flow characteristics of external gear pump[J]. Journal of drainage and irrigation machinery engineering,2014,32(2):108-112.(in Chinese)
[10]梁开洪,张克危,许丽,等.轴流泵叶顶间隙流动的计算流体动力分析[J].华中科技大学学报(自然科学版),2004,32(9):36-38.LIANG Kaihong,ZHANG Kewei,XU Li,et al. Fuzzy dynamic analysis of axial flow of axial-flow pump[J].Journal of Huazhong University of Science and Technology(natural science edition),2004,32(9):36-38.(in Chinese)
[11]张双全,符建平,段开林,等.三峡水轮机尾水管涡带的CFD数值模拟[J].华中科技大学学报(自然科学版),2006,34(7):19-20.ZHANG Shuangquan,FU Jianping,DUAN Kailin,et al.Fuzzy simulation of turbine vortex in the Three Gorges turbine[J]. Huazhong University of Science and Technology(natural science edition),2006,34(7):19-20.(in Chinese)