scholarly journals Discussion: “Critical-Heat-Flux and Flow-Pattern Observations for Low-Pressure Water Flowing in Tubes” (Bergles, A. E., Lopina, R. F., and Fiori, M. P., 1967, ASME J. Heat Transfer, 89, pp. 69–74)

1968 ◽  
Vol 90 (2) ◽  
pp. 280-280
Author(s):  
H. K. Fauske
1982 ◽  
Vol 56 (1) ◽  
pp. 134-140
Author(s):  
Paul Robershotte ◽  
Peter Griffith

Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake ◽  
Tomonari Yamada

Boiling heat transfer of thin-rectangular channels of the width of 10 mm has been examined. The height of the flow channel was in a range from 0.6 mm to 0.4 mm. Experimental fluid was water. Bubbly flow, slug flow, semi annular flow and annular flow were observed. The flow pattern transition agreed well with the Baker flow pattern map for the usual sized flow path. The critical heat flux was lower than the value of the usual sized flow channel. The Koizumi and Ueda method predicted well the trend of the critical heat flux of the present experiments. At the critical heat flux condition, the heat transfer surface was covered by liquid slug, a large bubble pushed away the liquid slug, a dry area was formed on the heat transfer surface and then liquid slug came around to cover the heat transfer surface again. This process repeated rapidly. Following this observation, a heat transfer surface temperature calculation model at the critical heat flux condition was proposed. The calculated result re produced the experimental result.


1967 ◽  
Vol 89 (1) ◽  
pp. 69-74 ◽  
Author(s):  
A. E. Bergles ◽  
R. F. Lopina ◽  
M. P. Fiori

This paper summarizes the results of an investigation of the critical-heat-flux condition for bulk boiling of water in uniformly heated round tubes where the inlet conditions were subcooled and exit pressures were below 100 psia. Choked flow was found to be prevalent under these conditions. The critical heat flux is shown to be a complex function of both local and inlet conditions. Detailed flow-pattern observations were made with an electrical probe. Many of the trends in the critical-heat-flux data can be related to the flow-pattern instability caused by slug flow.


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