The operation of self-actuated valves in suction and discharge processes plays a crucial role in the thermal efficiency and structural reliability of hermetic reciprocating compressors. The present work provides a thorough description of an in-house numerical method based on a partitioned fluid-structure interaction algorithm intended to obtain high-fidelity numerical predictions and optimise valve system design. A large eddy simulation model is used for the turbulent flow, whereas a normal mode superposition assumption along with an impact penalty method is used for the reed. Under this framework, a detailed analysis of the coupled problem with a straight and tapered exit ports is carried out. Differences in effective flow area and pressure drop are found as a result of the port geometry, but also of the valve velocity