Investigation of flow field characteristics in hose pumps under various operating conditions and their impact on gap leakage

Abstract

Addressing the issue of leakage in practical scenarios involving hose pumps, this paper conducts an analysis on hose pumps with existing compression gaps. The model is simplified to represent the two-dimensional Newtonian fluid pulsating flow of a single-sided sine wave passing through the tube. The study derives the axial flow velocity distribution within the tube while establishing correlations between the leakage volume, tube clearance, pressure differential, deformed cross-sectional length of the tube, rotor speed (which exhibits a negative correlation), the deformation length of the tube in the x-direction, and the fluid's dynamic viscosity (demonstrating a positive correlation). Utilizing a bidirectional fluid-structure coupling method, this analysis investigates hose pumps with compression gaps. Specifically, it examines the flow field pressure, velocity, and vortex intensity of two Newtonian fluids with Reynolds numbers of 10–30 and 6000–15 000, respectively, within a 180° bend tube with a curvature-to-inner-diameter ratio of 4.6. This analysis is conducted under inlet velocities of 0.32 and 0.6 m/s, and outlet pressures of 0 and 0.1 MPa. The study identifies the positions of extreme leakage rates, elucidating the flow field characteristics and their impact on leakage. Furthermore, it investigates the causes of secondary flows within the tube, concluding that the fluid inside the tube exhibits symmetric helical motion. This research establishes the periodic variations in flow field vortex intensity and secondary flow intensity, along with the conclusion that leakage rates are positively correlated with axial vortex intensity and negatively correlated with secondary flow intensity.