Analysis of cavitation and shear in bellows pump: transient CFD modelling and high-speed visualization

Pneumatic drive bellows pumps (PDBPs) are a crucial fluid control component in the semiconductor industry. However, when dealing with specific chemical mechanical polishing (CMP) slurries, agglomeration of particles can occur, leading to scratches, particle residues, pits, and other defects on wafer surface. The cause has been proposed be cavitation excessive shear PDBPs. A high-fidelity multiphase computational dynamics (CFD) model, which fully resolves response check valves under hydrodynamic external loads, was established evaluate behaviour distribution Moreover, test rig built visualize cavitating flow patterns PDBPs verify accuracy CFD model. Among different regions captured by high-speed visualization, region near inner edge end-ring inlet valve is dominant, high intensity, long duration, complex morphology evolution. Detailed initiation development process cavities dominant analysed numerically. rate domains estimated, domain stands out from other. strongest observed end-ring. Furthermore, an analysis relationship between indicates that high-intensity vortices generated owing strong account for inception cavitation. This study contributes understanding details provides guideline further optimization similar pumps.