用于高转速液压泵吸油增压的离心泵设计与可视化研究

Design and Visualization of Centrifugal Pumps for Suction Pressurization of High Speed Hydraulic Pumps

液压泵高转速化时容易出现吸油不充分从而引发吸空,提升液压泵的入口压力可以缓解这一现象。为此,设计一种用于高转速液压泵前置增压的离心泵。通过CFD仿真与可视化试验相结合的方法,揭示其内部流动本质。结果表明:所设计的增压离心泵产生空化时的临界转速为2400 r/min,当转速超过临界转速时,叶片压力面开始产生空化,空化产生的气泡向叶片的吸力面与尾部移动,尾部处的气泡受叶片的切削破碎为小气泡游离在蜗壳内;随着转速的升高,油液内的空化现象越明显,气泡数目也逐渐增多,但泵内流型始终为气泡流。

Hydraulic pumps are prone to insufficient oil suction at high speeds,which can lead to suction emptying,and this phenomenon can be alleviated by increasing the inlet pressure of the hydraulic pump.For this reason,a centrifugal pump was designed for the pre-pressurization of high speed hydraulic pumps.The internal flow nature was revealed by a combination of CFD simulations and visualization tests.The results show that the design of the critical speed is 2400 r/min when the designed pressurized centrifugal pump produces cavitation,when the speed exceeds the critical speed,cavitation begins to produce at the blade pressure surface,the produced cavitation bubbles move towards the suction surface and tail of the blades,the bubbles at the tail are broken into small bubbles by the blade cutting and dissociate in the volute.As the speed increases,the cavitation phenomenon within the oil fluid is more obvious,and the number of bubbles gradually increases,but the flow pattern within the pump is always bubble flow.