Two-phase pressure drop of water during flow boiling in a vertical narrow channel

• Published in: Experimental thermal and fluid science Vol. 28; no. 2; pp. 131 - 138
• Main Authors: Wen, D.S., Kenning, D.B.R.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 2004; Elsevier Science
• Subjects: Applied sciences; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat exchangers (included heat transformers, condensers, cooling towers); Two phase flow; Pressure drop; Vertical pipe; Heat exchanger; Compact heat exchanger; Narrow channel; Experimental study; Boiling
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/S0894-1777(03)00031-1

Two-phase pressure drop during flow boiling of water in a vertical channel with cross-section 2 mm by 1 mm was investigated experimentally. The experiments were performed for the conditions of heat flux from 25 to 105 kW/m
2, mass flux from 57 to 211 kg/m
2s and exit quality from 9% to 30%, including the influence of inlet compressibility. The two-phase pressure distribution along the channel was recorded at 200 Hz sampling frequency. The results were compared with four correlations. The Lockhart–Martinelli correlation for pressure drop in large tubes with modified
C value has been shown to be still applicable with uncertainty of 35%. The homogeneous model had an uncertainty of 50%; the Tran and Chisholm methods over-estimated the experimental data by 100% and 300% respectively. It is shown that none of these correlations can predict published pressure drop data for water during flow boiling in a 50 by 70 micron channel.