Agitated thin film evaporator (ATFE) is a new type of high-efficiency evaporator that is forced to form a film through a rotating scraper, which can realize the smooth evaporation of high-viscosity non-Newtonian flow materials. The flow distribution and transmission mechanism of the materials in the evaporator directly determine the evaporation efficiency and power consumption of the evaporator. Different from the previous study mainly based on Newtonian flow, this paper establishes a three-dimensional computational fluid dynamics model of ATFE for non-Newtonian flow with different viscosity, and systematically probes the flow field distribution characteristics and film forming mechanism in the evaporator. The results show that the flow field distribution characteristics of low-viscosity non-Newtonian flow are similar to those of Newtonian flow, the material can be formed a uniform and continuous liquid film on the wall; as the viscosity increases, the uniformity and continuity of the liquid film gradually deteriorate. Through the study of the flow field distribution and transmission form of the materials, combined with the liquid film distribution, velocity distribution, shear strain rate distribution, and viscosity distribution, it is found that the shear field and viscosity distribution formed by the internal structure and operating state of the evaporator are the key to build good film formation. In addition, it is proposed that making an angle in the periphery of the blade can assist the film forming of the high-viscosity fluid, and also probes the optimal scraper angle. This research provides theoretical guidance and basis for the design and application of ATFE.
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