The Design And Flow Simulation Of The Roto-Jet Pump's Pick-Up Tube And Rotating Case

The Roto-Jet pump is a new kind of very low specific speed pump which is developed in recent years. It is always used in carbin black, food production, chemical industry and deep well mining system to supply the steady outflow with low flux and high pressure. The work theory of the Roto-Jet pump is very specific and it has very simple construction and smooth performance curve and cheap maintain. Our country began to introduce this pumps in 1990s. The research on it is very poor now especially on the flow in the pick-up tube and rotating case. The pick-up tube is one of the most important overflowing parts, and its design result will directly influent the efficiency of the Roto-Jet pump. All the research on this pump is analysis by synthesis in this paper and many models are designed according to the real condition. The flow in the pick-up tube and rotating case is researched by numerical simulation. One part of this paper is the researching of the design and flow of the pick-up tube. The design of the pick-up tube accords to the research on the roto-jet pump by other people in China and a new type model is designed. A parameterize designing software is made by Delphi 6.0. Numerical simulation on the three-dimensional turbulence flow in the pick-up tube is based on Reynolds time-average Navier-Stokes equations. The k-εTurbulence-closed model is used in this paper. In the near wall area the standard wall function is used. The finite difference discrete is applied on controlling equations after they are converting into the body fitted coordinate system. SIMPLEC algorithm is used to solve the velocity and pressure field. So that the distribution of the velocity, pressure and kinetic energy in the pick-up tube is shown to us by numerical simulation. We can compare the models through analysising the velocity and pressure. We get that: the new type model has same performance as the old one. Cavitation is liable to appear in the first elbow. The angle of flare is always less than 5o. The shape of the pick-up's inlet influence the internal pressure much.Another part of this paper is numerical simulation of the flow in the rotating case. Because the rotating case rotates with impellers with high speed, the flow in it can't be measured by means of experiments. The stationarypick-up tube will influence the flow in the rotating case. So that the distribution of the velocity, pressure and kinetic energy in the rotating case is shown to us by numerical simulation. We get that: Velocity in the rotating case linearly changes along the radius and velocity changes little on the axis direction. Pressure in the rotating case has the same value. Velocity, pressure and kinetic energy change a lot around the inlet of the pick-up tube, so it should be importance design. Aerofoil around the diffuse segment of the pick-up tube influences the flow in the rotating case little.