Pool Boiling Enhancement of R-123 Using Perforated Plates

Title & Authors
Pool Boiling Enhancement of R-123 Using Perforated Plates
Kim, Nae-Hyun;

Abstract
In this study, we investigate the pool boiling enhancement caused by perforated plates on top of a smooth surface. We conduct tests using R-123 at atmospheric pressure. It was shown that perforated plates significantly enhanced the pool boiling of the smooth surface. The reason may be attributed to the increased bubble contact area between the plates. The results showed that the enhancement ratio was dependent on the heat flux. At high heat flux, the enhancement ratio increased as the porosity increased. However, at low heat flux, the enhancement ratio decreased as the porosity increased. For the present investigation, the optimum configuration had a pore diameter of 2.0 mm, pore pitch of $\small{2.5mm{\times}5.0mm}$ or $\small{5.0mm{\times}5.0mm}$, and a gap width of 0.5 mm, which yielded heat-transfer coefficients that are close to those of GEWA-T. The optimum porosity for R-123 was significantly larger than that of water or ethanol. The reason for this may be the large liquid-to-vapor density ratio along with the small latent heat of vaporization of R-123. The perforated plates yielded smaller boiling hysteresis compared with that of the smooth surface.
Keywords
Heat Transfer Coeffcient;Heat Transfer Enhancement;Perforated Plate;Pool Boiling;
Language
Korean
Cited by
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