AUTHORS: Shoji Mori, Ryuta Yanagisawa

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ABSTRACT: A honeycomb-structured ceramic porous plate (HPP) was used to increase the critical heat flux (CHF) in a saturated pool boiling. The HPP employed was a commercially available filter normally used to purify exhaust gases from combustion engines. Combining the HPP with a nanofluid significantly improved the CHF compared to that obtained from a plain surface in pure water, to a maximum of approximately 3.2 MW/m2 . In this paper, the mechanism for the CHF enhancement was considered by measuring the temperature of the heated surface using an ITO heater and a high-speed infrared camera. As a result, the following conclusions can be made based on the out data. The average temperatures at the intersecting parts of the HPP were relatively high (more than 200 °C) compared to other locations. And when the HPP was installed on the heated surface in conjunction with the nanofluid, the wall temperatures obtained under burnout conditions decreased in the order of the intersection of an HPP wall > an HPP wall between intersections > the cell. However, dryout was initiated in the cell and a wall temperature of 330 °C was first obtained in this location when burnout occurred. This result implies that further CHF improvements could be achieved if the initiation of dryout at the cell can be suppressed.

KEYWORDS: boiling, CHF enhancement, IR camera, honeycomb porous plate

REFERENCES:

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