中国物理B ›› 2024, Vol. 33 ›› Issue (8): 84701-084701.doi: 10.1088/1674-1056/ad4323

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Influence of liquid film shape on evaporation performance of agitated thin film evaporator

Xin-Qiang Gu(顾鑫强), Yao Huang(黄瑶), Kun Zou(邹鲲), and Yi-Tian Peng(彭倚天)†   

  1. College of Mechanical Engineering, Donghua University, Shanghai 201620, China
  • 收稿日期:2024-01-26 修回日期:2024-03-26 出版日期:2024-08-15 发布日期:2024-07-30
  • 通讯作者: Yi-Tian Peng E-mail:yitianpeng@dhu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 52375172, 52075093, and 51905089).

Influence of liquid film shape on evaporation performance of agitated thin film evaporator

Xin-Qiang Gu(顾鑫强), Yao Huang(黄瑶), Kun Zou(邹鲲), and Yi-Tian Peng(彭倚天)†   

  1. College of Mechanical Engineering, Donghua University, Shanghai 201620, China
  • Received:2024-01-26 Revised:2024-03-26 Online:2024-08-15 Published:2024-07-30
  • Contact: Yi-Tian Peng E-mail:yitianpeng@dhu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 52375172, 52075093, and 51905089).

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摘要： The agitated thin film evaporator (ATFE), which is known for its high efficiency, force the material to form a film through the scraping process of a scraper, followed by evaporation and purification. The complex shape of the liquid film inside the evaporator can significantly affect its evaporation capability. This work explores how change in shape of the liquid films affect the evaporation of the materials with non-Newtonian characteristics, achieved by changing the structure of the scraper. Examining the distribution of circumferential temperature, viscosity, and mass transfer of the flat liquid film shows that the film evaporates rapidly in shear-thinning region. Various wavy liquid films are developed by using shear-thinning theory, emphasizing the flow condition in the thinning area and the factors contributing to the exceptional evaporation capability. Further exploration is conducted on the spread patterns of the wavy liquid film and flat liquid film on the evaporation wall throughout the process. It is noted that breaking the wavy liquid film on the evaporating wall during evaporation is challenging due to its film-forming condition. For which the fundamental causes are demonstrated by acquiring the data regarding the flow rate and temperature of the liquid film. The definitive findings of the analysis reveal a significant improvement in the evaporation capability of the wavy liquid film. This enhancement is attributed to increasing the shear-thinning areas and maintaining the overall shape of the film throughout the entire evaporation process.

关键词: liquid film shape, shear-thinning fluids, flow characteristics, evaporative heat transfer

Abstract: The agitated thin film evaporator (ATFE), which is known for its high efficiency, force the material to form a film through the scraping process of a scraper, followed by evaporation and purification. The complex shape of the liquid film inside the evaporator can significantly affect its evaporation capability. This work explores how change in shape of the liquid films affect the evaporation of the materials with non-Newtonian characteristics, achieved by changing the structure of the scraper. Examining the distribution of circumferential temperature, viscosity, and mass transfer of the flat liquid film shows that the film evaporates rapidly in shear-thinning region. Various wavy liquid films are developed by using shear-thinning theory, emphasizing the flow condition in the thinning area and the factors contributing to the exceptional evaporation capability. Further exploration is conducted on the spread patterns of the wavy liquid film and flat liquid film on the evaporation wall throughout the process. It is noted that breaking the wavy liquid film on the evaporating wall during evaporation is challenging due to its film-forming condition. For which the fundamental causes are demonstrated by acquiring the data regarding the flow rate and temperature of the liquid film. The definitive findings of the analysis reveal a significant improvement in the evaporation capability of the wavy liquid film. This enhancement is attributed to increasing the shear-thinning areas and maintaining the overall shape of the film throughout the entire evaporation process.

Key words: liquid film shape, shear-thinning fluids, flow characteristics, evaporative heat transfer

中图分类号:  (Computational methods in fluid dynamics)

  • 47.11.-j
47.50.-d (Non-Newtonian fluid flows) 47.61.Jd (Multiphase flows) 64.70.fm (Thermodynamics studies of evaporation and condensation)