基于导流方法的真空吸鱼泵改进与试验

针对真空吸鱼泵起捕过程中存在鱼体损伤和起捕效率低的问题,该研究对集鱼罐的结构和吸鱼泵的工作方式进行改进。进鱼管穿过集鱼罐底进入集鱼罐内部,在进鱼管的顶部设置倒置的喇叭状导流结构,起捕时,鱼水混合物进入集鱼罐后分离,鱼留在集鱼罐内,水被排出集鱼罐。以鱼水比1:1时的数据做比较基准,当鱼水比分别为1:2、1:3、1:4、1:5时,经计算,输送相同质量的鱼,改进吸鱼泵用时比真空吸鱼泵分别减少20.4%、30.6%、36.8%和40.8%。开展真空吸鱼泵和改进吸鱼泵吸水过程的数值模拟分析并进行试验验证。结果表明,与真空吸鱼泵样机相比,改进吸鱼泵的集鱼罐内涡流不明显,输送能力不随鱼的提升高度而变化;改进吸鱼泵的输鱼友好性更强,鱼体无损伤。研究结果可为大型鱼类起捕装置设计提供理论依据和参考。

Improving the performance of vacuum fish pumps using diversion method

Deep-sea aquaculture has developed rapidly in the world in recent years. Aquaculture equipment is required for large-scale, mechanization, automation, and intelligence. Among them, the vacuum fish pump has been used widely in the process of fish catching and conveying. However there is a large range of strong vortexes in the tank during operation, leading to the mutual friction and collision injury between fish. In this study, the structure of the tank and the operation mode were improved to reduce the fish injury for the high working efficiency using a vacuum fish pump. The fish passed through the inlet pipe into the bottom of the tank and then entered the inside of the tank. A trumpet-shaped diversion structure was placed upside down at the top of the inlet pipe. An industrial centrifugal pump was selected as the driving device to replace the water ring vacuum fish pump. The water inlet of the centrifugal pump was connected to the water outlet of the tank. The fish-water mixture entered the tank, where the fish was separated from the water, due to the suction effect of the centrifugal pump. The incoming fish stayed in the tank, but the incoming water was discharged from the tank by the centrifugal pump. The baseline ratio of fish to water was 1:1 in the pool and the tank. When the ratio of fish to water in the pool was 1:2, 1:3, 1:4, and 1:5, respectively, it was calculated that the conveying time of the improved fish pump was reduced by 20.4%, 30.6%, 36.8%, and 40.8%, respectively, compared with the vacuum fish pump for conveying fish with the same quality. The numerical simulation was carried out to compare the water absorption of the vacuum and the improved fish pump using computational fluid dynamics. The results showed that there was a small vortex range in the tank of the improved fish pump, indicating the weak vortex intensity. An improved fish pump prototype was also designed and then manufactured to verify the numerical simulation in the performance experiments. Compared with the performance of the vacuum fish pump prototype, there was a relatively small vortex in the tank of the improved fish pump, and the conveying capacity remained changed with the change of fish lifting height. The improved fish pump was more friendly to fish conveying. The probability of fish injury was greatly reduced as well. The findings can provide a strong reference for the design of a large fish pump.