Multiobjective Optimization of Clogging Performance in Nonpressure Screen Filters

To explore the effect of irrigation water containing organic impurities on the clogging performance of nonpressure screen filters, this study employed a multiobjective optimization method that considers both initial flow and water quality. Filter cake porosity, pressure drop, and thickness were chosen as evaluation indicators. Predictive models for each indicator were developed using the response surface methodology (RSM) to analyze their variation patterns and quantify the contribution rates of the influencing factors. A subjective-objective integrated weighting approach combined with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was then applied to the Pareto optimal solutions, enabling a comprehensive performance evaluation and optimization of the clogging behavior. The results indicate that filter cake porosity peaks (exceeding 0.9) at an organic matter content of 0.35–0.45. The pressure drop increases significantly with higher flow, rising by more than 30% as the flow increases from 120 to 160 m3·h−1. Meanwhile, filter cake thickness shows an approximately linear increase with both flow rate and impurity concentration, nearly doubling at 160 m3·h−1 compared with that at 120 m3·h−1. The sand to organic matter ratio is the primary controlling factor for porosity (contribution rate: 2.183) and thickness (contribution rate: 2.909), while the initial flow predominantly governs pressure drop (contribution rate: 1.417). Using the combined weighting method, the weights of each evaluation indicator for filter cake clogging performance were determined as follows: filter cake pressure drop (50.579%) > filter cake porosity (35.811%) > filter cake thickness (13.610%). For irrigation water sources with a high concentration of impurities, a medium-low flow is recommended for nonpressure screen filters to optimize the balance between system energy consumption and impurity removal capacity. These results provide decision-making references for the application of nonpressure screen filters.