Heat Transfer and Bubble Movement of Two-Side and One-Side Heating Subcooled Flow Boiling in Vertical Narrow Channels

2006 ◽  
Vol 128 (8) ◽  
pp. 838 ◽  
Author(s):  
Liang-Ming Pan ◽  
Tien-Chien Jen ◽  
Chuan He ◽  
Ming-dao Xin ◽  
Qing-hua Chen
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Subcooled Flow Boiling ◽  
Narrow Channels ◽  
Subcooled Flow ◽  
Bubble Movement

Heat Transfer and Bubble Movement of Double- and Single-Side Heating Subcooled Flow Boiling in Narrow Channels

2005 ◽  
Author(s):  
Liang-Ming Pan ◽  
Chuan He ◽  
Ming-Dao Xin ◽  
Tien-Chien Jen ◽  
Qinghua Chen
Keyword(s):  
Heat Transfer ◽  
Flow Boiling ◽  
Narrow Channel ◽  
Nucleate Boiling ◽  
Bubble Behavior ◽  
Subcooled Flow Boiling ◽  
Narrow Channels ◽  
Subcooled Flow ◽  
Single Side ◽  
Micro Channels

Compared with conventional channels, narrow and micro channels have significant heat transfer enhancement characteristic. With smooth internal surface, such channels can efficiently avoid encrustation at the washing of the high-speed liquid. Moreover, heat transfer elements can be easily assembled. These types of channels have been adopted extensively in many engineering applications, e.g. microelectronic cooling, advanced nuclear reactor, cryogenic, aviation and space technology and thermal engineering. Geometrical size of flow passage-away affects heat exchange of flow boiling, with the result that the bubble in narrow channel acts very different from those in non-narrow channel. This paper experimentally compared the bubble behavior with different heating methods of narrow rectangular channels, and the bubble behavior of subcooled flow boiling of R-12 in the narrow channels both with double side and single heating. Experimental settings are: the heating length of test-section is 400 mm, the cross-section is 35 mm in width and 2mm in gap size, mass flux is 700∼1500 kg.m−2.s−1, the heat flux is 25∼70kW.m−2 and the pressure is 1.3∼2.0 MPa. Comparisons were made on Onset of Nucleate Boiling (ONB) point and bubble characters with various flow patterns. Results revealed that the characteristics of double and single side heating shown good agreement with proper modifications.

Calcium Carbonate Scale Formation During Subcooled Flow Boiling

1997 ◽  
Vol 119 (4) ◽  
pp. 767-775 ◽  
Author(s):  
S. H. Najibi ◽  
H. Mu¨ller-Steinhagen ◽  
M. Jamialahmadi
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Calcium Carbonate ◽  
Flow Boiling ◽  
Fluid Velocity ◽  
Nucleate Boiling ◽  
Operating Conditions ◽  
Initial Surface ◽  
Subcooled Flow Boiling ◽  
Subcooled Flow

Scale deposition on the heat transfer surfaces from water containing dissolved salts considerably reduces fuel economy and performance of the heat transfer equipment. In general, this problem is more serious during nucleate boiling due to the mechanisms of bubble formation and detachment. In this study, a large number of experiments were performed to determine the effect of fluid velocity, initial surface temperature, and bulk concentration on the rate of calcium carbonate deposition on heat transfer surfaces during subcooled flow boiling. A physically sound prediction model for the deposition process under these operating conditions has been developed which predicts the experimental data with good accuracy. Two previously published models are also discussed and used to predict the experimental data.

Sign in / Sign up

Export Citation Format

Share Document