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

Autor(es)

Nunes, Jessica Martha ^[1] ; Souza, Reinaldo Rodrigues de ^[1] ; Rodrigues, Alessandro Roger ^[2] ; Safaei, Mohammad Reza ^{[3, 4]} ; Cardoso, Elaine Maria ^[1]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Society of Mechanical Sciences and Engineering; v. 42, n. 3 FEB 15 2020.
• Citações Web of Science: 0

Resumo

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)

• Processo FAPESP: 13/15431-7 - Análise da aplicação de nanotecnologia em processos térmicos e de conversão de energia
• Beneficiário: Elaine Maria Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 16/02034-8 - Análise da aplicação de nanotecnologia em processos térmicos e de conversão de energia
• Beneficiário: Vitor Fernando Prado da Silva
• Modalidade de apoio: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico
• Processo FAPESP: 14/19497-5 - Estudo teórico e experimental da Influência de nanofluidos sobre a ebulição nucleada
• Beneficiário: Leonardo Lachi Manetti
• Modalidade de apoio: Bolsas no Brasil - Mestrado
• Processo FAPESP: 19/02566-8 - Caracterização experimental do desempenho térmico e hidrodinâmico de dissipadores de calor microaletados durante a ebulição convectiva
• Beneficiário: Elaine Maria Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Regular