Design Theory Of Submersible Mixer Impeller And Numerical Simulation Of Agitated Flow Field

With the development of industrialization and urbanization, urban sewage emissions dramatically, the submersible mixer as major sewage treatment equipment is very important to sewage treatment for its effect of mixing and pushing the flow, but its impeller design methods also lack the systematically theoretical guidance. Therefore, in order to improve the mixing effects effectively, it is an urgent need to have a scientific and systematic design theory and methods of submersible mixer to guide industrial production.Based on above consideration, this paper deeply discusses the propeller whirlpool theory and its mathematical models, the hydraulic design of submersible mixer impeller, 3-D modeling technique, and internal 3-D incompressible turbulent flow calculation of agitated flow field. The main work of the paper consists of:1. A brief description of the submersible mixer impeller development at home and abroad is introduced. By the comparison of various mixer impellers, we can find that the propeller-mixer impeller has some performance characteristics: high efficiency of mixing, low flow-miss ability, low consumption, and sheared moderately.2. By deeply studying the circulation theory of ship propeller, we can sum up the design method of propeller based on the circulation theory.3. The PEO/ENGINEER software was applied to design the submersible mixer impeller. The grid-generated technique along with respective feature was introduced and the free surface mesh generation method based on the algebraic way was quoted. The hydraulics professional software Gambit was used to carry on generating unstructured grid of the agitated flow field.4. The twin-equation mode and law of the wall was adopted to enclose N-S's equation. The turbulent flow mode based on Reynolds time-averaged control equations and k - ε two-equation turbulent mode was adopted. The SIMPLEC's algorithm was used to solve the N-S's equation. The numerical simulation of the internal 3-D incompressible turbulent flow agitated flow field was carried out according to different design parameter. The results showed that: the mixer impeller produced vortex jet flow, the constant velocity lines advanced as ellipse, the velocity along the centerline are larger than others, and utilized volume flow to transport the liquid.5. By changing some design parameters of mixer impeller, we can compare and analyze the numerical simulation results and find that: for the same impeller diameter,...