| In this study,the net hanging test was carried out in the breeding cage of Fugu Group Redfin Fugu in Zhuang he City for half a year in the breeding season,and the characteristics of the attachment of the net coat were analyzed.An impact-jet coupling net coat in situ cleaning scheme was proposed.The cleaning blade,cleaning nozzle and cleaning disk were designed.The nozzle structure and key structural parameters were optimized by using Fluent fluid simulation technology,and the test bench of the net cage cleaning device was designed and trial-produced,Carry out orthogonal test to optimize nozzle cleaning operation parameters,verify the correctness of simulation results and the feasibility of impact-jet coupling mesh cleaning scheme,and provide theoretical basis and technical support for the research and development of mechanized mesh cleaning equipment for aquaculture cage.The specific research is as follows:From May 2021 to November 2021,the attachment net hanging test was carried out,and the results showed that there were 21 species of main attachment organisms in the Wang jia Island sea area,among which the dominant species were Mytilus edulis,Ulva lactuca,Enteromorpha clathrata Greville,Symphyocladia latiuscula,Caprella scaura,Clytia sp,and Ciona intestinalis.During the test period,the coverage first increased and then decreased.Summer was the peak period of adhesion,and the coverage rate decreased with the increase of water depth.The biological characteristics,growth rules and mechanical characteristics of the mussel were analyzed.The shell length of the mussel was significantly positively correlated with the shell width and shell thickness,and the shell length,shell width,shell thickness and body weight showed a very significant power function relationship.When measuring the compressive strength of mussels,there is a yield point on the curve.The compressive strength in the direction of shell length,shell width and shell thickness increases in turn,and the maximum crushing force is 195.91 N.A impact-jet coupling mesh cleaning device and the design of mesh cleaning test bench are developed and designed.The cleaning device is composed of rotary joint,cleaning blade,cleaning nozzle,diverter pipe and universal joint.The test bench is composed of test water tank,electric slide,cleaning bracket,cleaning plate,rotary joint,push rod motor and high-pressure plunger pump.The design,calculation and selection of key components such as cleaning disc,cleaning blade and sliding table are carried out.The size of cleaning disc is determined to be 240 mm in diameter,120 mm in width,25 mm in length and 20 mm in width,the lifting speed of sliding table is 0～80mm/s,and the stroke of push rod motor is 0～200mm.Fluent was used to analyze the change law of flow velocity and gas volume fraction of three types of nozzles,namely,abrupt,conical and arc-shaped nozzles.The jet and cavitation performance of abrupt nozzle was the best.Orthogonal experiment was designed to simulate the influence of the length of the throat,the outlet angle and the outlet diameter of the abrupt nozzle on the cavitation performance,and the optimal structural parameters combination of the nozzle was determined as follows: the length of the throat was 3mm,the outlet diameter was 1.4mm,the outlet angle was 45 °,and the gas volume fraction reached 85% under this parameter.According to the simulation and optimization results in the early stage,a trial-production mesh cleaning test bench was designed,and orthogonal experiments were carried out to study the influence of nozzle operating parameters on cavitation performance,and the performance of the whole cleaning device was tested.The results show that the pump pressure has the greatest impact on cavitation,followed by the target distance,and the nozzle angle has the smallest impact.When the pump pressure is 25 MPa,the target distance is 10 mm,and the included angle is 15 °,the cleaning effect is the best,and the cleaning rate of mussel can reach 82.5%. |
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