Analysis About Flow Field And Performance Prediction For Roto-jet Pump

The Roto-Jet pump is a new kind of very low specific speed pump, which has many characters, such as low flux, high pressure, smooth Q-H curve, simple construction. It's efficiency is higher about 10-20% than the centrifugal pump which are at the same specific speed. It is always used in the industry of oil, chemical, metallurgy, paper making, fire fighting. Because start relatively late in fastenning the research of gushing out the pump at home, it is not deep enough and overall to study, especially of the pick-up tube and rotating case, it is still relatively low to cause the efficiency of this type pump, it is less to use. Therefore, it has very important theory value and well applical foreground to research in the rule of flow field inside the Roto-Jet pump and it's design technique.This paper descripes the principle,structure and design principles of roto-jet pump,thus lay a solid theoretical foundation for the thorough expermental research and numerical simulation on the roto-jet pump.We design the expermental projedt according to standard of roto-jet pump, do the expermental research on the model of roto- jet pump, then get the accurate results and performance curves. On this basis , we can choose reasonable expermental points for the numerical simulation.With the help of softaware Pro/Engineer, the solid model is established and assembled.Using software CFX,the flow field inside front channel, pick-up tube and rotating case is simulated by the standarded k-εturbulence model and SIMPLEC algorithm ,getting the pressure and velocity field.The hydraulic performance of roto-jet pump such as head , efficiency and sharft power are got by data calculation,which provide guiding role in project for the optimization and development in roto-jet pump.Comparing with the experimental data, the simulation data proves that roto-jt pump can be simulated by CFX,which makes the basis for the following work.The three models of compound impeller with short and long blade ,single closed impeller,single semi-open impeller and double semi-open impeller ,are simulated.We can get the three models'pressure field , velocity field and performance curves.By analysis and comparison, the single closed impeller is better than the two others. On the basis of single closed impeller,with the same method ,the two roto-jet pump models which are used different impellers: impeller with rectangle channel, compound impeller with short and long blade being simulated and compared,we can drew the conculsions: the velocity of flow field inside rotating case of impeller with rectangle channel is greater, but the velocity of flow field inside pick-up tube is the same with the other,so ,comparing with the pump with compound impeller with short and long blade ,the kinetic energy can be better translated into pressure energy,meaning that it can get graeter pressure difference between inlet and outlet, graeter pump head.Through the comparing ,the pump with impeller with rectangle channel is better than the other.