Design and experimental research on key components of net cleaning equipment for deep-water cage

In order to solve the problem of lack of cleaning equipment for large-scale net cage aquaculture in China, we desinged a net cleaning equipment for deep-water cage aquaculture based on the principle of high-pressure jet cavitation. Then we established the hydrodynamic characteristic analysis equation of key components of cleaning equipment by using mathematical modeling and physical experimental methods. Besides, we conducted underwater cleaning experiments to investigate the effects of nozzle diameter, nozzle to rotating discs angle (Angle between nozzle axis and diversion rotary disc surface), and target distance on the biological removal rate of cleaning equipment under different working conditions. The results show that the biological removal rate of fouling on the net hanging board was influenced by multiple factors such as target distance, nozzle diameter and nozzle to rotating discs angle. Within the experimental parameter range, the biological removal rate of fouling on the net cleaning equipment was 30.26%–72.55%. Within the range of test parameters, when the nozzle diameter was 1.0 mm, the nozzle to rotating discs angle was 60°, and the target distance was 0 cm. The removal rate of fouling organisms on the net hanging boards was the highest. The effect of target distance on the removal rate of biofouling on the net hanging boards was the most significant. Under the impact of cavitation jet from net cleaning equipment, shellfish fouling organisms mainly fell off in the form of shell fragmentation. With the main residue being soft shellfish silk discs with strong adsorption capacity. The results optimize the parameter configuration of underwater cleaning equipment, providing theoretical support for the design of net cleaning equipment for cage aquaculture.