Structural Optimization Based on Response Surface Methodology for the Venturi Injector Used in Fertigation System

To enhance the hydraulic performance of the Venturi injector, the effects of the structural parameters were investigated using response surface methodology (RSM) and computational fluid dynamics (CFD) simulations. The fertilizer suction chamber diameter, contraction angle, and throat diameter ratio were chosen as variables, while the suction flow rate, suction concentration, and suction efficiency were selected as performance indicators. Multiple regression models were established, and the regression models were used for parameter optimization and experimental verification. The results showed that under the same inlet-outlet differential pressure, with the increase in the fertilizer suction chamber diameter, contraction angle, and throat diameter ratio, the suction flow rate, suction concentration, and suction efficiency showed a trend of first increasing and then decreasing, and there were peaks in suction performance. Predictive regression equations were established for the suction flow rate, concentration, and efficiency within the experimental parameter range. The determination coefficients of the three regression equations were 0.9987, 0.9961, and 0.9990, respectively, which indicated that the established regression equations could be used for performance prediction. The optimized combination of structural parameters included a fertilizer suction chamber diameter of 32 mm, a contraction angle of 35°, and a throat diameter ratio of 2.93. The error between the predicted and experimental values was less than 3%, indicating a high level of reliability in the predictive regression model. The performance indicators of the optimized Venturi injector were significantly improved, with an increase of 124.1~793.7 L h−1 in the suction flow rate, 9.52~16.42 percentage points in suction concentration, and 5.4~9.19 percentage points in suction efficiency.