Roughness and surface material effects on nucleate boiling heat transfer from cylindrical surfaces to refrigerants R-134a and R-123

Autor(es)

Jabardo, Jose M. Saiz ^[1] ; Ribatski, Gherhardt ^[2] ; Stelute, Elvio ^[2]

Afiliação do(s) autor(es)

^[1] Univ A Coruna, Escuela Politecn Super, Ferrol 15403, Coruna - Spain

^[2] Univ Sao Paulo, EESC, Dept Mech Engn, BR-13566590 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: EXPERIMENTAL THERMAL AND FLUID SCIENCE; v. 33, n. 4, p. 579-590, APR 2009.
• Citações Web of Science: 39

Resumo

This paper presents results of an experimental investigation carried out to determine the effects of the surface roughness of different materials on nucleate boiling heat transfer of refrigerants R-134a and R-123. Experiments have been performed over cylindrical surfaces of copper, brass and stainless steel. Surfaces have been treated by different methods in order to obtain an average roughness, Ra, varying from 0.03 mu m to 10.5 mu m. Boiling curves at different reduced pressures have been raised as part of the investigation. The obtained results have shown significant effects of the surface material, with brass being the best performing and stainless steel the worst. Polished surfaces seem to present slightly better performance than the sand paper roughened. Boiling on very rough surfaces presents a peculiar behavior characterized by good thermal performance at low heat fluxes, the performance deteriorating at high heat fluxes with respect to smoother surfaces. (C) 2008 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 01/00417-1 - Efeito da rugosidade superficial na ebulicao nucleada dos refrigerantes halogenados r-11 e r-123.
• Beneficiário: Elvio Buganca Stelute
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 06/52089-1 - Estudo teorico experimental da ebulicao convectiva de refrigerantes halogenados no interior de micro canais.
• Beneficiário: Gherhardt Ribatski
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores