Simulation And Optimization Research Of The Jet Pump Internal Flow Field

Jet pump is a kind of fluid machinery and mixing equipment, using high-speed fluid as working motivation. It has a lot of advantages, such as: simple structure,low cost,easy processing,good sealing,can work stable in various harsh conditions and so on. It has been widely used in every industry of national economy, and produced significant economic benefits. In agricultural plant protection machinery, it mainly used as pump for adding water,adding pesticide and jet mixing apparatus. The jet pump's low efficiency for energy transmission and quality transmission limits its further development. How to improve jet pump efficiency in every environment has been a big problem for experts at home and abroad.Previous studies mainly focus on partial configuration optimization to the influence of the pump whole performance. This paper begin with the structure, mainly study mixing situation in the pump with different density fluid, and the influence of inside surface roughness to the pump whole performance. Main contents are as follows:1. The paper discusses the development and present situation of jet pump design and application, theoretically analyzes the internal characteristics and cavitation characteristics of jet pump, preliminary masters the internal flow theory of jet pump.2. This paper introduces the principle of CFD technology and the procedures of numerical simulation, using PRO/E,CAD soft for three and two-dimensional modeling, using GAMBIT soft to divide model mesh, numerical simulating the internal flow of jet pump, contrasting the result of numerical simulation and experiment. The result proves the correctness of the numerical simulation.3. The paper using standard k-εturbulence model to numerical simulate the mixing situation of different density fluid in the jet mixing apparatus, which is the contractible model of jet pump. The paper simulates three situations, which are the density of inhaled fluid: 1.03 t /m~3,1.1 t /m~3,1.18 t /m~3 NaCl solution, and working fluid is water.4. The paper simulates internal flow situation of inhaled height: -1m and 1m, simultaneously, the paper extends the throat pipe to 24mm and 36mm, and simulates their internal flow situation respectively.5. The paper chooses six working pressure,seven different density NaCl solution for inhaled fluid and five heights for experiment designing, using experiment results to study the internal flow of jet mixing apparatus, simultaneously, contrasting the result of numerical simulation and experiment. The result proves the correctness of the numerical simulation. 6. The paper theoretically discusses the influence of internal friction loss coefficient to the jet pump whole performance, using FLUENT soft set the inside surface roughness to 0.3 and 0.5, and contrasting two numerical simulation result to state the influence of different inside surface roughness to the performance of jet pump.