A hermetic variable speed rotary compressor has a substantially vertically oriented drive shaft, by which the oil is driven upwards and delivered to the lubricating components. To avoid oil starvation or excessive oil supply over a wide range of working speed, it is essential to understand the flow characteristics in such a centrifugal oil pump. In this study, a novel test rig has been built to perform the measurements of oil flow rate under various operating conditions. Several key design parameters in relation to the flow rate such as oil inlet diameter, oil viscosity and oil level height in oil sump have been discussed in detail. The results indicate that the oil flow rate increases up to the speed at which the flow stagnation appears and then starts to slightly decrease with the speed. The stagnation speed decreases with the oil inlet diameter but increases with an augment in oil level height. The oil viscosity does not considerably affect the stagnation speed. Based on the simulated results, it is found that the gas region at oil inlet expands and the effective oil flow area reduces when the rotational speed is high enough. Such behavior of oil flow could be one potential explanation to the occurrence of flow rate stagnation.

封闭式变速旋转压缩机具有基本垂直定向的驱动轴，通过该驱动轴，油被向上驱动并输送到润滑部件。为了避免在宽泛的工作速度范围内出现缺油或过多供油的情况，必须了解这种离心式油泵的流量特性。在这项研究中，已经建造了一种新颖的试验台，以在各种工况下进行油流量的测量。与流量有关的几个关键设计参数，如进油口直径，机油粘度和油底壳中的油位高度已被详细讨论。结果表明，机油流速增加到出现停滞的速度，然后开始随速度略微降低。停滞速度随着进油口直径的增加而降低，但随着油位高度的增加而增加。油的粘度不会显着影响停滞速度。根据模拟结果，发现当转速足够高时，进油口处的气体区域会扩大，有效油流面积会减少。油流的这种行为可能是流速停滞发生的一种潜在解释。