Abstract：Clarifying the coupled influence of the local scraper geometry and rotational speed on the liquid-film/head-wave hydrodynamics is crucial for the optimal design and operation of scraper-type molecular distillers. A three-dimension transient CFD model was developed using the VOF multiphase approach coupled with the RNG k-ε turbulence model. The flow field was characterized by liquid volume fraction, mean radial/axial velocities, and turbulence-related features. The results show increasing the scraper angle strengthens the radial component and makes the liquid adhere more closely to the scraper surface, thereby hindering effective film spreading, whereas an excessively small angle weakens mechanical driving and film renewal. Increasing the scraper width from 2.0 to 8.0 mm enhances contact and momentum transfer, improving radial spreading and axial renewal; however, widths beyond 8.0 mm introduce excessive resistance and reduce the flow intensity. Higher rotational speeds enhance the centrifugal effect and facilitate uniform film formation and evaporation, while overly high speeds may cause splashing and film non-uniformity. Within the investigated geometry and operating window, a scraper angle of 45°, a width of 8.0 mm, and a rotational speed of 150 r/min provide the most stable and uniform flow field, offering a theoretical basis for structural and operational optimization.
LIU Shuyu,SU Xiang,HAN Ce et al. Numerical Simulation of the Effect of Scraper Structure on Flow Field Distribution for Molecular Distillation[J]. Chemical Reaction Engineering and Technology, 2026, 42(1): 36-45.
