关键词: 能量损失, 喷嘴, 水射流系统

Abstract: The nozzle, which is the load to the pump and converts pressure energy into kinetic energy, is one of very important parts of water jet system. Under different conditions, the nozzle energy conversion efficiency is different, resulting in the effect of system efficiency. Due to the cause of formation, the energy loss of a nozzle is classified as feature energy loss and cavitation energy ones. Based on the flow characteristics, the influence factors and the relation with flow coefficient are investigated. Experiments are carried out to study the flow characteristics of cylinder nozzles, cone nozzles and cosine nozzles and, the effects of the inlet/outlet conditions and the nozzle features are addressed. Comparison analyses have been made on the feature and cavitation energy loss of the three nozzles. The results show that the inlet conditions greatly influence the cavitation energy loss and have little effects on feature ones, and that the nozzle features significantly affected both kinds of energy losses and they tend to be smaller when the inner surface is closer to streamline. The related conclusions provide a basis for the nozzle optimal design and the improvement of the efficiency of water jet system.

Key words: Energy loss, Nozzle, Water jet system