| Texto completo | |
| Autor(es): |
Moreira, Debora C.
;
Ribatski, Gherhardt
;
Kandlikar, Satish G.
;
Amer Soc Mech Engineers
Número total de Autores: 4
|
| Tipo de documento: | Artigo Científico |
| Fonte: | PROCEEDINGS OF THE ASME 2020 18TH INTERNATIONAL CONFERENCE ON NANOCHANNELS, MICROCHANNELS, AND MINICHANNELS (ICNMM2020); v. N/A, p. 6-pg., 2020-01-01. |
| Resumo | |
This paper presents a comparison of heat transfer and pressure drop during single-phase flows inside diverging, converging, and uniform microgaps using distilled water as the working fluid. The microgaps were created on a plain heated copper surface with a polysulfone cover that was either uniform or tapered with an angle of 3.4 degrees. The average gap height was 400 microns and the length and width dimensions were 10 mm x 10 mm, resulting in an average hydraulic diameter of approximately 800 microns for all configurations. Experiments were conducted at atmospheric pressure and the inlet temperature was set to 30 degrees C. Heat transfer and pressure drop data were acquired for flow rates varying from 57 to 485 ml/min and the surface temperature was monitored not to exceed 90 degrees C to avoid bubble nucleation, so the heat flux varied from 35 to 153 W/cm(2) depending on the flow rate. The uniform configuration resulted in the lowest pressure drop, and the diverging one showed slightly higher pressure drop values than the converging configuration, possibly because the flow is most constrained at the inlet section, where the fluid is colder and presents higher viscosity. In addition, a minor dependence of pressure drop with heat flux was observed due to temperature dependent properties. The best heat transfer performance was obtained with the converging configuration, which was especially significant at low flow rates. This behavior could be explained by an increase in the heat transfer coefficient due to flow acceleration in converging gaps, which compensates the decrease in temperature difference between the fluid and the surface due to fluid heating along the gap. Overall, the comparison between the three configurations shows that converging microgaps have better performance than uniform or diverging ones for single-phase flows, and such effect is more pronounced at lower flow rates, when the fluid experiences higher temperature changes. (AU) | |
| Processo FAPESP: | 15/24834-3 - Desenvolvimento de dissipadores de calor de alto desempenho baseados em multi-microcanais contendo superfícies micro- e nanoestruturadas visando aplicações em receptores solares |
| Beneficiário: | Debora Carneiro Moreira |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 16/09509-1 - Processos de transferência de calor com mudança de fase de elevado desempenho aplicados ao aproveitamento de energia solar |
| Beneficiário: | Gherhardt Ribatski |
| Modalidade de apoio: | Auxílio à Pesquisa - Temático |
| Processo FAPESP: | 17/12576-5 - Projeto e caracterização experimental de absorvedores térmicos baseados em microcanais para coletores solares |
| Beneficiário: | Debora Carneiro Moreira |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado |