射流式离心泵不同喉管长度对自吸性能的影响

Effect of jet centrifugal pump with different throat lengths on performance of self-priming

为研究射流式离心泵喉管长度对泵自吸性能的影响规律,运用CFX软件提供的EulerianEulerian多相流模型,对不同喉管圆柱段长度的射流式离心泵内部气液两相流动进行定常数值模拟,得到泵内部压力、气相速度以及气相体积分数的变化规律,分析其对自吸性能的性影响,并通过试验进行验证.模拟结果表明:当喉管圆柱段长度为10 mm时,喉管处静压值将降低,卷吸作用得到加强,且其轴线上的气相过流速度进一步提高,整体增强了气相分离能力,泵的自吸性能明显提高;当喉管圆柱段长度为15 mm时,其对射流器内部静压值以及气相速度影响甚微,由于流动损失增加导致做功能力减弱,泵的水力性能降低.试验发现:当喉管圆柱段为10 mm时,自吸高度由原来的7. 45 m提高至9. 15 m,自吸时间也由原来的148. 5 s缩短至90. 0 s左右,自吸性能得到明显提高,且满足设计运行要求.

In order to study effect of jet centrifugal pump with different throat lengths on the perfor-mance of self-priming,the steady numerical simulation of gas-liquid two-phase flow in a jet centrifugal pump with different throat lengths was carried out with the Eulerian-Eulerian multiphase flow mo-del of the CFX software.The internal pressure,gas velocity and gas phase volume fraction of the jet centrifugal pump were obtained by numerical simulation and the self-priming performance of the jet centrifugal pump was analyzed and verified by experiments.The results of simulation show that when throat length is 10 mm,the static pressure in throat cylinder decreases,the entrainment action is strengthened,and the gas phase velocity on the axis increases,the gas phase separation capacity will be enhanced,and the self-priming performance of the pump is improved.When throat length is 15 mm,it has a little effect on the static pressure and gas velocity of the jet centrifugal pump.The hydraulic performance of the pump becomes poor because of the increase of the flow loss.The experiments state that when throat length is 10 mm,self-priming performance has been significantly improved,and meets design requirements,with self-priming height increasing from 7.45 m to 9.15 m and self-priming time decreasing from 148.5 s to 90.0 s.