Research on the flow and cavitation characteristics of multi-stage throttle in water-hydraulics

In water-hydraulic power systems cavitation is more likely to happen than in oil-hydraulic power systems because of the high vaporous pressure of water. A multi-stage throttle, which consists of two or more orifices in a throttle, is an effective way to avoid or reduce cavitation damage. In this research, the cavitation characteristics of two-stage throttles are analysed theoretically and compared with a single-stage. Then, experiments are conducted to investigate the flow and cavitation characteristics of multi-stage throttles including two kinds of two-stage throttles and one of a three-stage kind. All the experiments are carried out under the two cases with and without backpressure, respectively. The working medium is tap water. Experimental results show that the shape of the multi-stage throttle and operating conditions have remarkable effects on the flow and cavitation characteristics.