Pressure distribution of the tooth top sealing clearance in three-screw pumps

This study primarily investigates the hydrodynamic pressure distribution in the gap flow of three-screw pump. This article focuses on high-performance three-screw pumps with 10-micron-level clearances. A numerical model is developed to analyze this pressure distribution within the gap between the screw rotor and bushing. Micro pressure sensors and eddy current transducers embedded in the pump bushing are employed to measure the hydrodynamic pressure distribution in the sealing clearance and the orbit of the satellite screws. Unlike other types of progressive cavity pumps, this study demonstrates for the first time that there is a significant dynamic pressure effect on the sealing gap between the top surface of the screw teeth and the bushing in a three-screw pump. In addition, in the theoretical realm, a pioneering breakthrough has been made for the first time in the mechanism analysis of screw-type pressure vessels under complex boundary conditions. The article reveals the pressure distribution characteristics of the gap flow field of three-screw pumps. The results reveal the existence of positive and negative zones of oil film pressure relative to adjacent chamber pressures, with the peak pressure significantly exceeding the outlet pressure. This also explains the mechanism by which the clearance of the three-screw pump significantly affects the action of the oil film excitation force, and ultimately significantly affects the vibration of the three-screw pump. The influence of the clearance design on the gap flow field is explored. The theory is employed to offer a substantial basis for work to design optimization of screw pumps.