Numerical Simulation Of Erosion Mechanism Within Centrifugal Pump

Most rivers in China belong to high silt-laden river, and along with our country industry's fast development, Liquid-solid two phase current centrifugal pumps'application is getting more and more widespread. The hydraulic performance of the centrifugal pump may be greatly descended, and the safety and stability of pump are threatened. Therefore, it is very important and significant for theory and reality to investigate the interior flow characteristic of Liquid-solid two phase current centrifugal pump.In this dissertation, numerical calculation of Centrifugal pump in the pure water and solid-liquid two-phase flow was carried out, and the performance of the pump was analyzed in detail. The main work and conclusions of this article are listed as follows:First, the research to wheel hub forehead of the centrifugal pump has been conducted:the circular cone speed is quite centralized in the crown, the inlet velocity distributes non-uniform, sand abrasion is quite big to the crown, but the minimal pressure strength is smallest. Velocity distribution when the ball is more evenly. However, with the increase of ball-like top, it will have the eddy current as the column and the minimal pressure strength is big. According to this findings, has determined centrifugal pump's computing geometry full-scale mockup.Second, both two-fluid model and particle trajectory model were adopted to the inner flow characteristic of runner in solid-liquid two-phase flow in the numerical simulation. Based on simulation result of two-phase fluid model, pressure distribution, velocity field, sand volume fraction on blade surface under different sand concentration and different sand diameters were analyzed. Particle trajectory model was used to investigate the region and the degree of runner blade abrasion in different conditions. The results showed that the great current capacity operating mode attrition is serious, the main attrition is at the leaf blade suction surface to the export, the leaf blade working surface at the entry and the exit, the small current capacity operating mode wears lightly, The sand density is bigger, the particle size is bigger, the distribution is more centralized, is bigger to centrifugal pump's attrition, the efficiency drops the scope is bigger. Third, used the two-fluid mode computation analyzes the mix sand to the centrifugal pump'influence. Contrast to computed result of the fifth chapter, it comes to the conclusion:when the mix sand particle size difference is big, the small sand's distributed region on leaf blade is big, the big sand's is small, other changes are almost consistent with single-size sand results.