This study presents the hydraulic characterization of a direct-acting pressure-reducing valve (PRV) using a combined experimental and numerical approach. An experimental test bench was implemented to measure inlet, control port, and outlet pressures over a flow rate range from 0 to 4.0 m3/h, under a constant inlet pressure of 8 bar and a set pressure of 3 bar. In parallel, a three-dimensional steady-state CFD model was developed using a sequential force balance analysis between hydraulic and spring restoring forces. The results show good agreement between numerical predictions and experimental data, with a maximum error below 10% in outlet pressure. The pressure drop exhibited a nonlinear increasing trend with flow rate, reaching values close to 1.8 bar at 4.0 m3/h. The flow coefficient Kv remained within a range of 2.2–3.0, while the pressure regulation coefficient S remained below 0.05, indicating stable regulation performance. Additional simulations at 25 bar provided improved agreement with manufacturer data, suggesting that catalog curves may be based on nominal pressure conditions. The proposed methodology demonstrates that steady-state CFD coupled with force balance analysis is an effective and computationally efficient approach for predicting the hydraulic behavior of direct-acting PRVs.
López-Villacís et al. (Tue,) studied this question.