Numerical study on hydraulic performance of submerged propellers in oxidation ditch

The submerged propeller is an efficient diving mix device,which is applicable for oxidation ditch treatment in industry,city and village wastewater-treatment plant. The impeller structure and reasonable rotating speed are important factors that determine flow field distribution and energy conversion efficiency. So it is necessary to use modern design methods to develop new kinds of high efficiency submerged propellers,and research the flow field characteristics of submerged propellers. On the basis of the existing form drawing,three-dimensional model of submerged propellers and unstructured tetrahedral mesh were generated. Based on Navier- Stokes equations and standard k- ε turbulence model,the flow was simulated by using a simple algorithm. Through changing some design parameters of propellers,the corresponding numerical simulation results reveal that for the same impeller diameter and service area of submerged propellers,the power consumption could be reduced effectively by optimizing blade mounting angle,which can determine the best blade mounting angle and most suitable rotational speed under given conditions. The study can provide theoretical and project guidance for submerged propellers design.

The submerged propeller is an efficient diving mix device, which is applicable for oxidation ditch treatment in industry, city and village wastewater-treatment plant. The impeller structure and reasonable rotating speed are important factors that determine flow field distribution and energy conver- sion efficiency. So it is necessary to use modern design methods to develop new kinds of high efficiency submerged propellers, and research the flow field characteristics of submerged propellers. On the basis of the existing form drawing, three-dimensional model of submerged propellers and unstructured tetra- hedral mesh were generated. Based on Navier - Stokes equations and standard k - 8 turbulence model, the flow was simulated by using a simple algorithm. Through changing some design parameters of pro- pellers, the corresponding numerical simulation results reveal that for the same impeller diameter and service area of submerged propellers, the power consumption could be reduced effectively by optimizing blade mounting angle, which can determine the best blade mounting angle and most suitable rotational speed under given conditions. The study can propellers design. provide theoretical and project guidance for submerged