Multi-parameter optimization of a double-row nozzle hydraulic collection device using orthogonal analysis and CFD-DEM joint simulations

The collection rate of the collection device in the deep-sea mining system directly affects the development prospects and economic benefits of the deep-sea mining system. Among the current mainstream hydraulic collection methods, this paper adopts orthogonal analysis and CFD-DEM joint simulation method to analyze the three parameters of front and rear nozzle aperture ratios (R_f-R_r), off-bottom height (H) and moving speed (V_m) of the double-row nozzle collection method. A solid-liquid coupled model that accounts for both internal and external flow fields is developed. Simulation analyses are conducted to examine the effects of various factors on two-phase flow dynamics. Orthogonal analysis methods are employed to investigate the comprehensive effects of parameter variations on collection rate and collection efficiency. The results reveal that H exerts the most significant influence on collection rate, while V_m has the greatest impact on collection efficiency. Based on the comprehensive data, a series of recommended parameter configurations for the double-row nozzle hydraulic collection device are proposed. Additionally, further analyses of the flow field conditions and nodule movements under optimal parameter configurations are undertaken. Finally, laboratory experiments with equal-sized nodules are carried out to validate the effectiveness of the coupled simulation method.