Research On Numerical Simulation Of Turbine Combined Agitator

Stirred equipments have been widely applied.The performance of stirred equipments directly affects product quality,production efficiency and cost.Therefore improving the performance and efficiency of stirred equipments has always been research focus.The experimental verification,numerical simulation and theoretical analysis are applied to research and analyze the flow field characteristics of the turbine agitator and its new combined agitators in the thesis.The main conclusions are as follows:(1)Through simulation study and comparative analysis of the axial,radial,and tangential velocities of the flow field in the stirred tanks with and without baffles,it is found that the baffles can restrain tangential flow,increase axial and radial flow and improve stirring effects.The flow field characteristics of the turbine agitator with blades in different tilt angles are also simulated and analyzed.It is found that the flow field pattern of the straight-blade paddle agitator is radial,and its power consumption is the largest.As the blade tilt angle decreases,the characteristics of the radial flow weak,the characteristics of the axial flow increase and the power consumption decreases.(2)According to the characteristics of a straight-blade impeller and a inclined-blade impeller agitator,two new turbine combined agitators are designed.Through simulation analysis,it can be known that the stirring effects of the flow filed between the upper and lower blades have been improved in the double-layer straight-inclined-blade alternating agitator.However,there is a certain degree of stratification between the upper and lower blades in the double-layer straight-inclined-blade dislocating agitator.In addition,compared with the double-layer straight-inclined-blade dislocating agitator,the double-layer straight-inclined-blade alternating agitator has larger velocity component,wider stirring range,greater stirring intensity and better stirring effect.(3)Through the simulation analysis of the flow field generated by the double-layer straight-inclined-blade alternating agitator in two different eccentric stirring methods,it can be found that the stirring range is wider,the stir is more uniform,the overall fluidity of the fluid and the mixing effect are better and the power consumption is less when the impeller works in reverse eccentric method.The flow field generated by the impeller in the reverse eccentric method has been further researched and the influence of the eccentricity in the flow field in the stirred tank has been also explored.The results show that the overall mixing effect of the flow field is the best and the stirring performance also improves when the eccentricity is 0.1.The research in the thesis has some engineering significance and reference value for the design and research of agitators.