Study of sand particle motion characteristics and distribution patterns in a helical-blade multiphase pump.

To reveal the dynamic characteristics and distribution patterns of sand particles in multiphase pumps used in closed oilfield gathering and transportation systems, this study focuses on a helical-blade multiphase pump. Through a systematic investigation of the effects of sand particle parameters (such as diameter, concentration, and shape) and pump operating parameters (including flow rate, rotational speed, and oil content) on the solid-liquid two-phase flow within the pump, the study aims to elucidate how these factors influence the internal motion behavior and spatial distribution of sand particles. The results indicate that sand particle diameter significantly influences two-phase flow trajectories, vortex structures, and particle motion, whereas the effects of concentration and shape are relatively weak. Higher flow rates and rotational speeds, combined with lower oil content, increase the kinetic energy of the fluid, thereby intensifying radial momentum fluctuations in the impeller. Axial momentum increases initially and then decreases with increasing particle size, rises with higher particle concentration, and remains unaffected by particle shape. Larger particles reduce transport efficiency, while higher concentrations increase the mass loading in key regions of the pump. High flow rates reduce the internal sand concentration, thereby facilitating transport; low rotational speeds increase sand concentration in critical locations. Increased oil content enhances fluid viscosity and drag forces, facilitating sand discharge. These findings provide theoretical insights into the coupled mechanisms of particle motion and energy dissipation in sand-laden multiphase flows, and offer practical guidance for anti-wear design and operational optimization of helical-blade multiphase pumps.