Analysis On Abrasion Rate Of The Screw Centrifugal Pump Based On DPM

As a new kind of solid-liquid two-phase flow pump, screw centrifugal pump combines the advantages of screw pump and centrifugal pump, and the special impeller structure can make use of their advantages sufficiently. Compared with the traditional solid-liquid two-phase flow pump, screw centrifugal pump has a series of strong points, such as: good through-flow condition, not easily blocking, high efficiency, longevity of service, low cost and steady power curve. And screw centrifugal pump has become a crucial equipment in transporting solid-liquid two-phase medium.Particles in solid-liquid two-phase flow can take part in screw centrifugal pump abrasion, and this behavior can make many problems, such as: low efficiency, high noise and short life in impeller and volute. The study of solid-liquid two-phase flow pump in China began in the early 1980 s, and compared to similar foreign advanced pump products, the efficiency generally 5% lower to 15%, foreign parts of solid-liquid two-phase flow pump life 10% higher than domestic product to 50%.The main research methods in studying solid-liquid two-phase flow pump abrasion have Mixture model and DPM, but they all have limitation. Mixture model determines the pump abrasion by particle volume distribution, but this method cannot calculate flow wall abrasion rate quantitatively. DPM doesn’t consider the influence of particles to fluid, this method applies only to the situation which volume fraction is less than 10%, and particles diameter use equivalent distribution method generally.This paper mainly analyzed screw centrifugal pump abrasion behavior in different working condition based on the theory of solid-liquid two-phase three-dimensional turbulent flow, combined with computational fluid dynamics numerical calculation method. Analysis abrasion position qualitatively, calculate abrasion rate quantitatively,and the result can offer a theoretical foundation in improving pump performance.Thesis research content and results are as follows:1. Based on DPM, analyzed screw centrifugal pump blade pressure side abrasive wear rule and internal flow field situation in different flow rate, particles density and solid volume fraction.2. Based on DPM, analyzed screw centrifugal pump flow component pressure and velocity trend in low solid volume fraction and velocity streamline.3. Based on the combination of Euler and DPM, analyzed screw centrifugal pumpabrasion position and rate in high volume fraction and complicated particles diameter.And compared with numerical simulation results in Mixture model, provided reliable evidence to proof the abrasion results.4. Analyzed screw centrifugal pump unsteady flow character quantitatively, set three monitor points in volute tongue and four monitor points in volute middle section.Obtained volute tongue pressure curve by time domain graph, and got middle section pressure curve by frequency domain graph.