Abstract:
In order to optimize the key equipment for deep-sea aquaculture cage netting cleaning, based on the cavitation jet principle, we investigated the influence of different geometric parameters of angular nozzles on cavitation jet characteristics to provide a reference for the optimal design of high-efficiency cleaning nozzles. We employed numerical simulation of cavitation water jets for angular nozzles using the Reynolds-Averaged Navier-Stokes (RANS) equations coupled with the Realizable k-ε Turbulence Model, the Volume of Fluid (VOF) Multiphase Flow Model, and the Schnerr-Sauer Cavitation Model. Besides, we designed 25 nozzle schemes with different structural parameters using an orthogonal experimental approach, and analyzed the effects of six parameters (Contraction length, cylindrical section length, diffusion section length, throat diameter, contraction angle, and expansion angle) on cavitation performance. The results indicate that the parameters ranked in descending order of influence on collapse distance: cylindrical section diameter
d>diverging angle
θ>contraction length
L2>diverging section length
L4>cylindrical section length
L3>converging angle \alpha ; while for vapor volume fraction: cylindrical section diameter
d>diverging angle
θ>diverging section length
L4>converging angle
α>contraction length
L2>cylindrical section length L_3. The cylindrical section diameter d was the dominant parameter affecting cavitation characteristics and exhibited a monotonic variation trend; the cylindrical section length L_3 had an optimum value; whereas the contraction length L_2, diverging section length L_4, and converging angle \alpha showed significant non-monotonic variations, reflecting complex interactions among the parameters.