Critical heat flux of subcooled boiling in high-heat-load narrow channels

The purpose of this study is to propose the critical heat flux (CHF) correlation for narrow one-side heated rectangular channels. CHF of subcooled flow boiling of water in narrow rectangular channels under the atmospheric pressure was measured parametrically. Experimental test channels were rectangular channels heated from one side with channel gap of 0.2-3.0 mm, channel of 7-22 mm, and heated length of 50-100 mm. CHF correlation for one-side heated rectangular channels was shown. Next, applicability of the correlation to the both-side heated rectangular channel, the half-circumferentially heated tube, and full-circumferentially heated tubes was examined. New CHF correlation for one- and both-side heated rectangular channels, and half- and full-circumferentially heated round tubes was proposed using critical quality, non-dimensional CHF parameter and heated perimeter ratio. Calculation error of the correlation is ±45% (Maximum 10 times better than the existing CHF evaluation equations which were proposed for the full-circumferentially heated tubes). (author)