Estimating the Impurity Concentration Factor on the Boiling Heat Transfer Surface of a Simulated Steam-Generator Tube-Support-Plate Crevice Using an in Situ High-Temperature Conductivity Measurement Technique

2000 ◽  
Vol 129 (3) ◽  
pp. 398-406 ◽  
Author(s):  
Hirotaka Kawamura ◽  
Hideo Hirano
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Measurement Technique ◽  
Impurity Concentration ◽  
Boiling Heat Transfer ◽  
Conductivity Measurement ◽  
Heat Transfer Surface ◽  
Temperature Conductivity ◽  
Support Plate

Flow Behavior and Flow Boiling Heat Transfer in Thin-Rectangular Mini-Channels

2008 ◽  
Author(s):  
Yasuo Koizumi ◽  
Hiroyasu Ohtake ◽  
Tomonari Yamada
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Pattern ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Annular Flow ◽  
Flow Channel ◽  
Heat Transfer Surface ◽  
Liquid Slug ◽  
Flux Condition

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.

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