Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization
This study employs the VOF model to conduct a numerical simulation of two-dimensional external falling film evaporation on micro-ribbed tubes. It aims to investigate the impact of various structural parameters of micro-ribs on the flow and heat transfer performance of the external falling film and d...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-04-01
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| Series: | Desalination and Water Treatment |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S194439862500089X |
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| _version_ | 1849471413847588864 |
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| author | Wei Zhang Ben Niu Zhen Liu Zhaoliang Wang |
| author_facet | Wei Zhang Ben Niu Zhen Liu Zhaoliang Wang |
| author_sort | Wei Zhang |
| collection | DOAJ |
| description | This study employs the VOF model to conduct a numerical simulation of two-dimensional external falling film evaporation on micro-ribbed tubes. It aims to investigate the impact of various structural parameters of micro-ribs on the flow and heat transfer performance of the external falling film and determine the optimal tube configuration under different conditions. The results show that the maximum deviation between the numerical calculation results and Parken's experimental results is less than 8 %. The results show that triangular micro-ribbed tubes exhibit a higher average heat transfer coefficient (hav) at moderate to high Γ (spray density). For the triangular-rib tubes, the hav shows a trend of initially increasing and then decreasing concerning structural parameters H(rib height), W(rib width), and N(rib number). At H= 0.4 mm, W= 1.6 mm, N = 32, compared with the smooth tube, the hav of the micro-ribbed tube is increased by 34.5 %. The alteration of structural parameters affects the local heat transfer coefficients (h) of the micro-ribbed wall (upper wall and lower wall) and the base-tube wall. The center of the upper wall and the base-tube wall of the micro-ribbed tube is the high heat transfer area, while the front and end of the lower wall and base wall are the low heat transfer area. The increased disturbances caused by vortices forming in the inter-rib region are primarily responsible for enhancing the hav. The size of the inter-rib region is the main reason for the generation of vortices. In addition, the thickness of the liquid film outside the micro-ribbed tube and the temperature gradient inside the liquid film also have important effects on heat transfer. |
| format | Article |
| id | doaj-art-3eb90ee9e826444ea8ca8f14c99391af |
| institution | Kabale University |
| issn | 1944-3986 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Desalination and Water Treatment |
| spelling | doaj-art-3eb90ee9e826444ea8ca8f14c99391af2025-08-20T03:24:51ZengElsevierDesalination and Water Treatment1944-39862025-04-0132210107310.1016/j.dwt.2025.101073Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimizationWei Zhang0Ben Niu1Zhen Liu2Zhaoliang Wang3College of New Energy, China University of Petroleum (East China), 66 West Changjiang Road, Qingdao 266580, China; Correspondence to: 66 West Changjiang Road, Qingdao, ChinaCollege of New Energy, China University of Petroleum (East China), 66 West Changjiang Road, Qingdao 266580, ChinaChina National Heavy Duty Truck Group Jinan Power Co., 777 Huaao Road, Jinan 250101, ChinaCollege of New Energy, China University of Petroleum (East China), 66 West Changjiang Road, Qingdao 266580, ChinaThis study employs the VOF model to conduct a numerical simulation of two-dimensional external falling film evaporation on micro-ribbed tubes. It aims to investigate the impact of various structural parameters of micro-ribs on the flow and heat transfer performance of the external falling film and determine the optimal tube configuration under different conditions. The results show that the maximum deviation between the numerical calculation results and Parken's experimental results is less than 8 %. The results show that triangular micro-ribbed tubes exhibit a higher average heat transfer coefficient (hav) at moderate to high Γ (spray density). For the triangular-rib tubes, the hav shows a trend of initially increasing and then decreasing concerning structural parameters H(rib height), W(rib width), and N(rib number). At H= 0.4 mm, W= 1.6 mm, N = 32, compared with the smooth tube, the hav of the micro-ribbed tube is increased by 34.5 %. The alteration of structural parameters affects the local heat transfer coefficients (h) of the micro-ribbed wall (upper wall and lower wall) and the base-tube wall. The center of the upper wall and the base-tube wall of the micro-ribbed tube is the high heat transfer area, while the front and end of the lower wall and base wall are the low heat transfer area. The increased disturbances caused by vortices forming in the inter-rib region are primarily responsible for enhancing the hav. The size of the inter-rib region is the main reason for the generation of vortices. In addition, the thickness of the liquid film outside the micro-ribbed tube and the temperature gradient inside the liquid film also have important effects on heat transfer.http://www.sciencedirect.com/science/article/pii/S194439862500089XFalling film heat transferNumerical simulationHeat transfer coefficientMicro-ribbed tubesLiquid film thickness |
| spellingShingle | Wei Zhang Ben Niu Zhen Liu Zhaoliang Wang Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization Desalination and Water Treatment Falling film heat transfer Numerical simulation Heat transfer coefficient Micro-ribbed tubes Liquid film thickness |
| title | Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization |
| title_full | Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization |
| title_fullStr | Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization |
| title_full_unstemmed | Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization |
| title_short | Numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization |
| title_sort | numerical investigation on heat transfer enhancement of falling film evaporation by surface structure optimization |
| topic | Falling film heat transfer Numerical simulation Heat transfer coefficient Micro-ribbed tubes Liquid film thickness |
| url | http://www.sciencedirect.com/science/article/pii/S194439862500089X |
| work_keys_str_mv | AT weizhang numericalinvestigationonheattransferenhancementoffallingfilmevaporationbysurfacestructureoptimization AT benniu numericalinvestigationonheattransferenhancementoffallingfilmevaporationbysurfacestructureoptimization AT zhenliu numericalinvestigationonheattransferenhancementoffallingfilmevaporationbysurfacestructureoptimization AT zhaoliangwang numericalinvestigationonheattransferenhancementoffallingfilmevaporationbysurfacestructureoptimization |