The effect of the cross-sectional geometry on saturated flow boiling heat transfer in horizontal micro-scale channels

Autor(es)

Sempertegui-Tapia, Daniel Felipe ^[1] ; Ribatski, Gherhardt ^[2]

Afiliação do(s) autor(es)

^[1] Brunel Univ, Coll Engn Design & Phys Sci, London - England

^[2] Univ Sao Paulo, EESC, Heat Transfer Res Grp, Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: EXPERIMENTAL THERMAL AND FLUID SCIENCE; v. 89, p. 98-109, DEC 2017.
• Citações Web of Science: 4

Resumo

In the present paper, convective boiling heat transfer results of R134a for circular, square and triangular tubes are presented. The evaluated channels present the same external perimeter and equivalent diameters of 1.100, 0.977 and 0.835 mm, respectively. Experiments were performed for mass velocities ranging from 200 to 800 kg/m(2) s, heat fluxes from 15 to 85 kW/m(2), saturation temperatures of 31 and 41 degrees C, and vapor qualities from 0.05 to 0.95. In order to perform reasonable comparisons among the test sections, the tests were run under similar mass velocities for the three geometries. The experimental data were carefully analyzed and discussed focusing on the effect of the cross-sectional geometry. It was found that for low heat fluxes, the heat transfer coefficient for the circular channel is higher. While for high heat fluxes, the heat transfer coefficient for the triangular channel is higher than for circular and square channels. Subsequently, the experimental data were compared with predictive methods from literature which are usually developed based only on data for single circular channels. Statistically, Kanizawa et al. {[}24] and Kim and Mudawar {[}34] provided reasonable predictions of the overall database. However, none of the methods captured adequately the experimental trends for the triangular channel. (AU)

• Processo FAPESP: 10/17605-4 - Análise experimental do efeito da geometria do micro canal no padrão de escoamento, coeficiente de transferência de calor e perda de pressão durante a ebulição convectiva
• Beneficiário: Daniel Felipe Sempértegui Tapia
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/50176-2 - Mitigação da emissão de gases de efeito estufa em sistemas de refrigeração mediante a utilização de gases com baixo GWP e a aplicação de micro e nanotecnologias
• Beneficiário: Gherhardt Ribatski
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Regular