Multi-step optimization design of pressure regulator for lateral inlet based on stepwise design of spring and structural

Installing a pressure regulator for laterals (PRL) at the non-pressure compensated drip tape inlet offers a cost-effective, uniform pressure control solution for irrigation, especially in developing countries. PRL regulate both flow and pressure, requiring high performance. However, traditional optimization methods face challenges like extensive experimentation and the risk of compromising certain metrics while optimizing others. This study proposes a multi-step optimization method combining Computational Fluid Dynamics (CFD) and response surface experiments. Results show that with optimal spring parameters, PRLs achieve a pressure deviation (α) of under 5 %, an outlet pressure deviation from inlet pressure (C_V) under 10 %, and a pressure difference (ΔP) of less than 0.02 MPa across a 300–1000 L/h flow range. Unstable pressure at low flow is caused by a gap between the regulating cup and housing. Optimizing the outlet angle reduces pressure deviation from flow variations. Key factors influencing preset pressure (P_set) are spring stiffness (K) and pre-compression length (ΔL), followed by the bottom surface radius (R_bottom) and cup thickness (R_up). For C_V, R_bottom and R_up are most significant, with minimal impact from parameter interactions. For ΔP, R_bottom, K, ΔL, and R_up, with significant interactions, are key factors. Based on comprehensive evaluations, three PRL variants with preset pressures of 0.08, 0.10, and 0.12 MPa were developed, offering improved performance: ΔH under 0.05 MPa, ΔP under 0.012 MPa, C_V under 5 %, and α under 1.5 %. These optimized PRLs significantly outperform the original design and offer a broader range of products.