The Flow Characteristic And Wear Characteristic In Single-stage Double-suction Centrifugal Pump Transport Silt Carrying Flow

There is high flow rate and convenient for maintenance in single-stage double-suction centrifugal pump and almost no axis force is generated because of the symmetric style impeller. So, it is widely used in some major projects such as "Yellow River irrigation project" and "South-to-North Water Diversion Project". To be compared with actual wear conditions, take a single-stage double-suction centrifugal pump (80SH-9.3) as object to research the flow and wear characteristic with sand water in this paper.Take the sand-laden water as transmission medium and assume that is incompressible. Based on Euler-Euler model and Euler-Lagrange model, also combine with3theory wear models (particle friction and collision model, Finnie erosion model and discrete collision wear model) to simulate the three-dimensional unsteady solid-liquid two-phase flow in single-stage double-suction centrifugal pump.Because the velocity of transmission medium is great influence on attrition rate inside the pump, and the velocity of sand water in suction chamber are slowly, this research is adopt Mixture model and DPM (Discrete Phase Model) and focus on the external characteristic of model pump and flow characteristic and wear characteristic inside the impeller and volute when transport sand water. The main research contents as follows:compared the different flow rate (0.8qv、qv、1.2qv), volume fraction of solid (2%、5%、10%) and diameter (0.019mm、0.036mm、0.076mm), and combined with the theoretical formula of sands water wear to made a quantitative analysis of the model pump research. Came to the following conclusions:1、the Mixture model can not calculate the laws of wear immediately. But it has shorter calculation time and better stability compare with DPM model. And in external characteristic:there is a very closely result exist between mixture model and pure water, the variation extent of flow rate, solid volume fraction and diameter are very small, it is different with practical.2、With the Mixture model:the friction wear intension of blade has a trend that increase first, and then decrease but increase again from inlet to outlet; the collision wear intension of blade is increase from inlet along the blade; the friction wear intension of pressure faces is stronger than suction faces at the inlet and outlet of blade. The friction wear intension is stronger than collision wear intension on the whole blade. Near the case tongue the wear intension is stronger. When flow rate becomes increasing, the friction wear intension increasing too, but the collision wear intension reach minimum under design flow condition; The collision wear intension of case wall under different flow rate are equal, and the intension of friction wear is minimum in design conditions. The wear intension becoming increase as the volume fraction of solid and the diameter increase.3、With the DPM model, the wear intension highest at the inlet and outlet of blade, and the wear intension on the pressure faces are higher than suction faces; the wear intension and area on hub is same as the other channel, mainly focus on the inlet of impeller and nearby the suction faces of blade; there are different levels of wear intension on the case and outlet of pump from casing tongue, and the wear intension on casing tongue are highest than other region. The wear intension becomes weak at the relevant position when flow rate increase, but increasing in each region when the volume fraction of solid or diameter increases.4、To explain the sand water flow characteristic and wear characteristic, the Mixture model combine the model based on the sand friction and collision move is a good choice, which can quantitative predict the change law of friction wear strength and collision wear strength along the blade or the case wall.