离心泵泵腔轴向间隙对平衡腔压力和泄漏量的影响

针对不同泵腔轴向间隙对平衡腔和泄漏量的影响,采用RNG k-ε湍流模型,对IS80-50-315型单级单吸悬臂式离心泵后泵腔间隙分别为1,4,8,12,16,20 mm的全流道模型进行数值计算,分析了不同间隙下平衡腔液体压力的分布规律和泄漏量的变化情况,得到了与泵腔阻力系数、密封环阻力系数和平衡孔阻力系数相关的速度系数与隙径比的关系曲线和泄漏量计算公式,可用于试验中对0.006~0.127的全流道速度系数进行预估和不同泵腔轴向间隙的泵腔流道液体泄漏量的求解.研究结果表明:后泵腔轴向间隙增大,平衡孔进口处平面和闷盖壁面压力随之升高,这个变化在轴向间隙为4~16 mm时较为明显,而在泵腔间隙取最大值12 mm和最小值1 mm时压力改变较小;同一工况下的泵腔流道泄漏量随后泵腔间隙的增大而上升,而对于同一泵腔间隙,泵腔流道泄漏量在0.8Q_d时最大,1.2Q_d时最小,即泄漏量随流量的增大而减小.

Effects of axial gap of impeller side cavity on pressure and leakage in balance chamber in centrifugal pump

In order to study influences of axial gap of impeller side cavity on pressure and leakage in the balance chamber of a centrifugal pump, the turbulent flows in the IS80-50-315 centrifugal pump were numerically simulated by using the RNG k-ε turbulence model when the axial gaps of impeller side cavity in the pump were 1, 4, 8, 12, 16 and 20 mm, respectively. The pressure distribution rules and variations of leakage with the gap size in the balance chamber were analyzed. An empirical formula of leakage was established based on the discharge coefficient, which was related to the dimensionless axial gap and the flow resistance coefficients across the side cavity, wear-ring gap and balance holes, respectively. The empirical relationship was applicable for the leakage prediction when the dimensionless axial gap was in a range of 0.006-0.127. It was found that the pressure in the balance chamber increased with increasing axial gap, especially for the gap in the range of 4 -16 mm. A little variation in the pressure was shown at the inlet of balance holes. The pressure on the wall of lid decreased with increasing cavity gap, but this phenomenon was not more obvious when the axial gap was 1 mm and 12 mm. Under the same working condition, the leakage increased with increasing axial gap. At a fixed axial gap, however, the leakage decreased with increasing pump flow rate.