Heat Transfer Performance And Structure Design Of The Scraped Thin-film Evaporator

The thin-film evaporator is a new-type highly efficient evaporatingequipment. It utilizes the high-speed rotation blade to disperse the fluid asuniform thin film so as to concentrate the material. It is especially suitablefor materials that are high-boiling，high viscosity and heat-sensitive. Up tonow the research of the evaporator has got some achievement，but thefoundational data for design is still limited. How to get the distribution ofthe velocity field, temperature field and concentration field, how toanalyze the fluid flow and the heat transfer performance is a valuableresearch subject.Based on the related literature at home and abroad in，the fluid flowand heat transfer process in thin-film evaporator are numerically simulated using CFD, and the velocity field and temperature field of the thin film areobtained. Especially, the parameters of the blades, for example bladelength, blade inclination angle and rotation speed, and mass flow-rate,material viscosity and inlet temperature on the fluid flow and heat transferprocess are preliminary analyzed. Also, the design process calculation andthe evaporator structure design are conducted.The simulation results show that the rotation speed and the bladeinclination angle have great effects on the fluid flow process in thethin-film evaporator. The high-speed rotation blade disperse the fluid asfully uniform thin film and increase the radical mixing of the fluideffectively, the radial velocity and total velocity of the fluid in thin-filmincrease obviously with the increase of blade inclination angle. The meanresidence time can be controlled by changing the inclination angle of theblade. The mass flow-rate and viscosity have great effects on heat transferprocess.