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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Influence of coated surfaces and gap size on boiling heat transfer of deionized water

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Nunes, Jessica Martha [1] ; Souza, Reinaldo Rodrigues de [1] ; Rodrigues, Alessandro Roger [2] ; Safaei, Mohammad Reza [3, 4] ; Cardoso, Elaine Maria [1]
Total Authors: 5
[1] UNESP Sao Paulo State Univ, Postgrad Program Mech Engn, Sch Engn, Ave Brasil 56, BR-15385000 Ilha Solteira, SP - Brazil
[2] Univ Sao Paulo, Dept Mech Engn, Sao Carlos Sch Engn, 400 Ave Trabalhador Sao Carlense, BR-13566590 Sao Carlos, SP - Brazil
[3] Ton Duc Tang Univ, Div Computat Phys, Inst Computat Sci, Ho Chi Minh City 758307 - Vietnam
[4] Ton Duc Thang Univ, Fac Elect & Elect Engn, Ho Chi Minh City 758307 - Vietnam
Total Affiliations: 4
Document type: Journal article
Source: Journal of the Brazilian Society of Mechanical Sciences and Engineering; v. 42, n. 3 FEB 15 2020.
Web of Science Citations: 0

Nanocoating techniques have been used to increase the heat transfer coefficient by changing the surface morphology, which could potentially increase the heat transfer in pool boiling systems. The present study aims to determine the influence of nanocoated surfaces and the gap size on the heat transfer coefficient and the critical heat flux during the pool boiling of deionized water, at saturation temperature in atmospheric pressure. Tests were performed on a copper heating bare surface with an average roughness of 0.330 mu m. The nanocoated surfaces were produced by alumina (Al2O3) nanoparticle deposition with 0.007% of volumetric concentration by using nanofluid boiling process. A gap size of 1.0 mm, corresponding to a Bond number equal to 0.4, was analyzed, and the results were compared with the cases without confinement. Concerning the heat transfer coefficient, the coated surface showed deterioration in the heat transfer performance (approximately 29%) as compared with the uncoated surface mainly due to the fouling resistance formed on the heating surface, confirmed by the surface characterization (SEM images). However, for coated surfaces and for confined cases, enhancement of 28% in the dryout heat flux was observed; the coating process significantly increases the surface wettability, which, in turn, increases the re-wetting capacity during the confined boiling process. Moreover, the heat transfer coefficient is more influenced by the gap size effect than the coating process. The chemical analysis showed that changes in the surface morphology occurred due to the effects of the confinement as compared to the original coated layer (the morphological aspect and melting mechanism were similar to the named liquid phase sintering). (AU)

FAPESP's process: 13/15431-7 - Application of nanotechnology in thermal processes and energy conversion
Grantee:Elaine Maria Cardoso
Support Opportunities: Research Grants - Young Investigators Grants
FAPESP's process: 14/19497-5 - Theoretical and experimental study of influence of nanofluid on the nucleate boiling regime
Grantee:Leonardo Lachi Manetti
Support Opportunities: Scholarships in Brazil - Master
FAPESP's process: 19/02566-8 - Hydrodynamic and thermal characteristics of single and two-phase flow in micro pin fin heat sinks
Grantee:Elaine Maria Cardoso
Support Opportunities: Regular Research Grants