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Technical Briefs

Experimental Study and Model on Critical Heat Flux of Refrigerant-123 and Water in Microchannels

[+] Author and Article Information
Wai Keat Kuan1

Systems and Technology Group, IBM Corporation, Research Triangle Park, NC 27709wkuan@us.ibm.com

Satish G. Kandlikar2

Thermal Analysis and Microfluidics Laboratory, Mechanical Engineering Department, Kate Gleason College of Engineering, Rochester Institute of Technology, Rochester, NY 14623sgkeme@rit.edu

1

Corresponding author.

2

Co-Author.

J. Heat Transfer 130(3), 034503 (Mar 06, 2008) (5 pages) doi:10.1115/1.2804936 History: Received July 31, 2006; Revised July 22, 2007; Published March 06, 2008

Abstract

The present work is aimed toward understanding the effect of flow boiling stability on critical heat flux (CHF) with Refrigerant 123 (R-123) and water in microchannel passages. Experimental data and theoretical model to predict the CHF are the focus of this work. The experimental test section has six parallel microchannels, with each having a cross-sectional area of $1054×157μm2$. The effect of flow instabilities in microchannels is investigated using flow restrictors at the inlet of each microchannel to stabilize the flow boiling process and avoid the backflow phenomena. This technique resulted in successfully stabilizing the flow boiling process. The present experimental CHF results are found to correlate best with existing correlations to overall mean absolute errors (MAEs) of 33.9% and 14.3% with R-123 and water, respectively, when using a macroscale rectangular equation by Katto (1981, “General Features of CHF of Forced Convection Boiling in Uniformly Heated Rectangular Channels  ,” Int. J. Heat Mass Transfer, 24, pp. 1413–1419). A theoretical analysis of flow boiling phenomena revealed that the ratio of evaporation momentum to surface tension forces is an important parameter. A theoretical CHF model is proposed using these underlying forces to represent CHF mechanism in microchannels, and its correlation agrees with the experimental data with MAE of 2.5%.

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Figures

Figure 1

Forces acting on a liquid-vapor interface

Figure 2

CHF data from present experiment with and without the 7.7% PDEs in manifold plotted against the Weber number, R-123

Figure 3

CHF data from present experiment with and without the 7.7% PDEs in manifold plotted against the Weber number, water

Figure 4

Qu and Mudawar (1) CHF data compared to the present Kandlikar and Kuan CHF model (Eq. 10), plotted against the Weber number, C=0.002492, water

Figure 5

Present R-123 CHF data with and without 7.7% PDE in manifold compared to the present Kandlikar and Kuan CHF model (Eq. 10), plotted against the Weber number, C=0.003139

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