POOL BOILING HEAT TRANSFER INSIDE A TWO-PHASE THERMOSYPHON CORRELATION OF EXPERIMENTAL DATA

Author(s):  
Ulrich Gross
Fractals ◽  
2008 ◽  
Vol 16 (01) ◽  
pp. 1-9 ◽  
Author(s):  
BOQI XIAO ◽  
ZONGCHI WANG ◽  
BOMING YU

A fractal model for the subcooled nucleate pool boiling heat transfer is proposed in this paper. The analytical expressions for the subcooled nucleate pool boiling heat transfer are derived based on the fractal distribution of nucleation sites on boiling surfaces. The proposed fractal model for the subcooled nucleate pool boiling heat transfer is found to be a function of wall superheat, liquid subcooling, fractal dimension, the minimum and maximum active cavity size, the contact angle and physical properties of fluid. No additional/new empirical constant is introduced, and the proposed model contains less empirical constants than the conventional models. The model predictions are compared with the existing experimental data, and fair agreement between the model predictions and experimental data is found for different liquid subcoolings.


Author(s):  
Qi Liu ◽  
Yuxin Wu ◽  
Yang Zhang ◽  
Junfu Lyu

Abstract A visual pool boiling experimental device based on ITO coating layer heater and high-speed shooting technology was established for studying the bubble behavior and heat transfer characteristics of saline solution, which is of great significance for ensuring heat transfer safety in nuclear power plants, steam injection boilers and seawater desalination. Volume of fluid method was applied to simulate numerically the liquid–vapor phase change by adding source terms in the continuity equation and energy equation. The predictions of the model are quantitatively verified against the experimental data. It can be found based on the experimental data that the pool boiling heat transfer coefficient is enhanced as the salt concentration increases. Visualization studies and numerical data have shown that the presence and precipitation of salt leads to a decrease in the detachment diameter and growth time of the bubble and an increase in the frequency of detachment, thereby increasing the pool boiling heat transfer coefficient.


2002 ◽  
Vol 124 (6) ◽  
pp. 1117-1124 ◽  
Author(s):  
Boming Yu ◽  
Ping Cheng

In this paper, a fractal model for nucleate pool boiling heat transfer is developed based on the fractal distribution of sites (areas) of nucleation sites on boiling surfaces. Algebraic expressions for the fractal dimension and area fraction of nucleation sites are derived, which are shown to be a strong function of wall superheat. The predicted fractal dimension is shown in good agreement with those determined by the box-counting method. The fractal model for nucleate boiling heat transfer is found to be a function of wall superheat, the contact angle of the fluid and the heater material, and physical properties of the fluid with a minimum number of empirical constants. The predicted total heat flux from a boiling surface based on the present fractal model is compared with existing experimental data. An excellent agreement between the model predictions and experimental data is found, which verifies the validity of the present fractal model.


1998 ◽  
Vol 29 (1-3) ◽  
pp. 196-207
Author(s):  
Haruhiko Ohta ◽  
Koichi Inoue ◽  
Suguru Yoshida ◽  
Tomoji S. Morita

1970 ◽  
Author(s):  
V. I. Subbotin ◽  
D. N. Sorokin ◽  
A.A, Tsiganok

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