Main discharge valve dynamics in variable wrap height compressors for electric vehicles: Decoupled FSI modeling with experimental validation

• A novel precision, fully structured flow domain model was developed for variable wrap height scroll compressors (VWHSC). • A fluid-solid decoupling method was employed to simulate the main discharge valve dynamics characteristics. • The nonlinear variation patterns of COP and discharge temperature in VWHSC under varying operating conditions were elucidated. • The opening/closing dynamics and flutter characteristics of the valve under varying operating conditions were elucidated. Electric scroll compressors are pivotal components in electric vehicle (EV) thermal management systems, enabling integrated cabin climate control (heating/cooling) and battery thermal regulation. Theoretical performance enhancements in these compressors can be achieved through scroll profile optimization or variable wrap height geometries to modulate the built-in volume ratio. Computational fluid dynamics (CFD) allows analysis of non-uniformities and dynamic flow mechanisms inside the chamber. However, most current CFD studies neglect the effects of discharge valves due to modeling complexity and prohibitive computational costs. This study develops a hexahedral-dominated structured mesh CFD model for variable wrap height scroll compressors (VWHSC), integrating discharge valve dynamics through the implicit coupling scheme that decouples fluid-structure interactions. The model demonstrates strong agreement with experimental data across rated discharge pressures and variable speeds, with temperature deviations constrained below 5.34 K and mass flow errors under 7.18 %. The coefficient of performance (COP) follows a convex parabolic trajectory with rotational speed, attaining a peak of 2.364 at rated pressure, with optimal COP shifting toward higher speeds under elevated pressures. Valve dynamics, governed by fluid force, inertial forces, rotational speed, discharge pressure, and central chamber pressure, reveal that increased speed amplifies valve opening angles and suppresses closure-phase flutter. Elevated discharge pressure similarly increases valve opening angles but narrows the fully open operating range, concurrently attenuating flutter phenomena. Flutter frequency reduction is achieved by suppressing chamber pulsation through modified volumetric variation patterns in the central chamber, implemented via discharge pipe enlargement or scroll tip geometry optimization. Incorporating valve dynamics enhances the VTHSC performance prediction accuracy and guides the development of optimized scroll design strategies.