Experimental and numerical investigation of flow and pressure drop in hydraulic quick connect couplings

Quick-connect couplings are essential components of hydraulic systems because they offer effective and convenient fluid-line connections. However, conventional ISO 16028 DN 6.3 flat-face valve designs often incur significant energy losses owing to turbulence, flow separation, and abrupt geometric transitions. This study combines experimental and numerical methods to investigate the pressure drops in these couplings, identifying critical energy-loss regions: the socket rear, valve-to-socket junction, and plug rear. Experimental measurements using a centrifugal pump, magnetic flow sensors, and pressure gauges were validated against numerical simulations performed in ANSYS Fluent using the k-ω (SST) turbulence model. The optimized coupling features smoother transitions, reduced contractions, and an innovative two-slot valve configuration, achieving a 2.22 × improvement in the flow coefficient (K_v = 1.46 vs. 0.68) and a pressure drop reduction from 1.120 bar to 0.244 bar at Re = 28,797. Additionally, peak flow velocity decreased by 51 % (from 16.73 m/s to 8.21 m/s), effectively eliminating cavitation risks. These enhancements comply with ISO 16028 standards while significantly improving the hydraulic efficiency. The bidirectional flow analysis revealed slightly higher pressure losses in the socket-to-plug direction, emphasizing the need for directional optimization. The design delivers lower operational costs, improved reliability, and reduced environmental impacts through energy savings, making it ideal for high-pressure systems and construction equipment. This study demonstrates a sustainable and practical solution, paving the way for future advances in quick-connect coupling designs.