Numerical analysis of film boiling heat transfer from a heated plate facing downwards : The case of saturated water at atmospheric pressure

2004 ◽  
Vol 2004.3 (0) ◽  
pp. 45-46
Author(s):  
Akihiro NAKANO ◽  
Satoru MOMOKI ◽  
Toru SHIGECHI
1966 ◽  
Vol 88 (1) ◽  
pp. 17-23 ◽  
Author(s):  
C. A. Heath ◽  
C. P. Costello

Ethanol, pentane, and Freon-113 were tested for atmospheric pressure, saturated film-boiling characteristics. Turbulent waves arise close to the bottom of vertical platinum plates and the data become identical to those obtained with horizontal plates, verifying an earlier contention by Y. P. Chang. The equation of Berenson fits the data for both horizontal and vertical heaters fairly well if modified for geometry, and the equation also correctly predicts the effect of acceleration on film-boiling heat-transfer coefficients. At high temperature differences, Berenson’s equation for the heat-transfer coefficient is slightly conservative, which is qualitatively predictable by analyzing the departures of the actual system from the idealized model of Berenson.


Author(s):  
Qiusheng Liu ◽  
Katsuya Fukuda

Forced convection film boiling heat transfer on a horizontal cylinder in saturated water and Freon-113 flowing upward perpendicular to the cylinder was measured for the flow velocities ranging from zero to 1 m/s at the system pressures ranging from 100 to 500 kPa: the platinum cylinders with the diameters ranging from 0.7 to 5 mm were used as the test cylinder heaters. The existing correlation for forced convection film boiling heat transfer given by Bromley et al. could not well describe the experimental data obtained, especially those for the higher pressures. The forced convection film boiling heat transfer correlation including the radiation contribution from the cylinders with various diameters for saturation conditions was developed based on forced convection two-phase laminar boundary layer film boiling model and the experimental data obtained. The experimental data agreed with the corresponding values derived from the correlation within ±15% for the flow velocities below 0.7 m/s, and within −30% to +15% for higher flow velocities. It was confirmed that the experimental data obtained by Bromley et al. for the horizontal carbon cylinders with the diameters ranging from 9.83 to 16.2 mm and with the significant radiation effect from the cylinder surfaces in various liquids for the various flow velocities up to 4.4 m/s at an atmospheric pressure agreed with the corresponding values derived from the new correlation within ±20%.


2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Li-Wu Fan ◽  
Jia-Qi Li ◽  
You-You Su ◽  
Huan-Li Wang ◽  
Ting Ji ◽  
...  

Pool film boiling was studied by visualized quenching experiments on stainless steel spheres in water at the atmospheric pressure. The surfaces of the spheres were coated to be superhydrophobic (SHB), having a static contact angle greater than 160 deg. Subcooled conditions were concerned parametrically with the subcooling degree being varied from 0 °C (saturated) to 70 °C. It was shown that film boiling is the overwhelming mode of heat transfer during the entire course of quenching as a result of the retention of stable vapor film surrounding the SHB spheres, even at very low wall superheat that normally corresponds to nucleate boiling. Pool boiling heat transfer is enhanced with increasing the subcooling degree, in agreement with the thinning trend of the vapor film thickness. The heat flux enhancement was found to be up to fivefold for the subcooling degree of 70 °C in comparison to the saturated case, at the wall superheat of 200 °C. A modified correlation in the ratio form was proposed to predict pool film boiling heat transfer from spheres as a function of the subcooling degree.


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