Numerical and Experimental Analysis of Internal Flow Characteristics of Four-Way Opposing Diaphragm Pump

This study investigates the steady-state behavior of a four-way opposed diaphragm pump. Simulations and experimental results confirm that peak stress locations align with observed damage sites. During the return stroke, diaphragm flipping induces tension at the flow-fixed interface edges, creating stress concentrations that contribute to fatigue and failure. Particle image velocimetry (PIV) shows that, under constant flow, increased voltage enhances umbrella valve opening, accelerates movement, broadens flow distribution, and disrupts symmetry. At 90°, valve-edge velocity exhibits sharp, high-amplitude oscillations and a narrow, elongated return region. Vortices near the valve port interfere with fluid motion, causing pressure fluctuations and potential sealing issues or increased opening resistance. Higher flow rates intensify vortex strength and shift their position, generating diaphragm pressure differentials that alter flow direction and velocity, reducing stability and inducing secondary vortices. Compared to a modified diaphragm, the standard type shows more complex vortex structures, greater flow instability, and dynamic response degradation under identical pressure and varying flow. These fragmented vortices further disrupt flow, affecting pump performance. The findings provide design insights for diaphragm pump optimization.