Influence of heat flux and pressure on heat transfer associated with fully developed nucleate pool boiling

1977 ◽  
Vol 33 (5) ◽  
pp. 1304-1306
Author(s):  
V. K. Andreev ◽  
V. I. Deev ◽  
A. K. Kondratenko ◽  
V. I. Petrovichev ◽  
V. E. Keilin ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Pool Boiling ◽  
Nucleate Pool Boiling

Effects of Heat Exchanger Tube Parameters on Nucleate Pool Boiling Heat Transfer

1998 ◽  
Vol 120 (2) ◽  
pp. 468-476 ◽  
Author(s):  
Moon-Hyun Chun ◽  
Myeong-Gie Kang
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Roughness ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Tube Diameter ◽  
Nucleate Pool Boiling ◽  
Pool Boiling Heat Transfer ◽  
Horizontal Tubes ◽  
Vertical Tubes

In an effort to determine the combined effects of major parameters of heat exchanger tubes on the nucleate pool boiling heat transfer in the scaled in-containment refueling water storage tank (IRWST) of advanced light water reactors (ALWRs), a total of 1966 data points for q″ versus ΔT have been obtained using various combinations of tube diameters, surface roughness, and tube orientations. The experimental results show that: (1) increased surface roughness increases the heat transfer coefficient for both horizontal and vertical tubes, and the effect of surface roughness is more pronounced for the vertical tubes compared to the horizontal tubes, (2) the two heat transfer mechanisms, i.e., increased heat transfer due to liquid agitation by bubbles generated and reduced heat transfer by the formation of large vapor slugs and bubble coalescence, are different in two regions of low heat flux (q″ ≤ 50 kW/m2) and high heat flux (q″ > 50 kW/m2) depending on the orientation of tubes and the degree of surface roughness, and (3) the heat transfer rate decreases as the tube diameter is increased for both horizontal and vertical tubes, but the effect of tube diameter on the nucleate pool boiling heat transfer for vertical tubes is greater than that for horizontal tubes. Two empirical heat transfer correlations for q″, one for horizontal tubes and the other for vertical tubes, are obtained in terms of surface roughness (ε) and tube diameter (D). In addition, a simple empirical correlation for nucleate pool boiling heat transfer coefficient (hb) is obtained as a function of heat flux (q″) only.

scholarly journals Predicting Conduction Heat Flux through Macrolayer in Nucleate Pool Boiling

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3893
Author(s):  
Mohd Danish ◽  
Mohammed K. Al Mesfer ◽  
Khursheed B. Ansari ◽  
Mudassir Hasan ◽  
Abdelfattah Amari ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Current Model ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Nucleate Pool Boiling ◽  
Conduction Heat Transfer ◽  
Wall Superheat

In the current work, the heat flux in nucleate pool boiling has been predicted using the macrolayer and latent heat evaporation model. The wall superheat (ΔT) and macrolayer thickness (δ) are the parameters considered for predicting the heat flux. The influence of operating parameters on instantaneous conduction heat flux and average heat flux across the macrolayer are investigated. A comparison of the findings of current model with Bhat’s decreasing macrolayer model revealed a close agreement under the nucleate pool boiling condition at high heat flux. It is suggested that conduction heat transfer strongly rely on macrolayer thickness and wall superheat. The wall superheat and macrolayer thickness is found to significantly contribute to conduction heat transfer. The predicted results closely agree with the findings of Bhat’s decreasing macrolayer model for higher values of wall superheat signifying the nucleate boiling. The predicted results of the proposed model and Bhat’s existing model are validated by the experimental data. The findings also endorse the claim that predominant mode of heat transfer from heater surface to boiling liquid is the conduction across the macrolayer at the significantly high heat flux region of nucleate boiling.

scholarly journals AN EXPERIMENTAL STUDY OF THE EFFECT OF SURFACTANT AND TI02 NANOPARTICLES ADDITIVES IN R141B ON THE NUCLEATE POOL BOILING PROCESS

2017 ◽  
Vol 39 (5) ◽  
pp. 37-40
Author(s):  
O. Khliyeva ◽  
T. Gordeychuk ◽  
A. Nikulin ◽  
N. Lukianov ◽  
V. Zhelezny
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Tio2 Nanoparticles ◽  
Pool Boiling ◽  
Nucleate Pool Boiling ◽  
Boiling Process ◽  
The Heat Transfer Coefficient

The results of experimental study of effect of TiO2 nanoparticles (0.1 % mass.) and surfactant Span80 (0.1 % mass.) additives in refrigerant R141b on the heat transfer coefficient of nucleate pool boiling process at three values of pressure 0.2, 0.3 and 0.4 MPa and range of heat flux from 5 to 70 kWm-2 are presented in paper.  

Nucleate boiling heat transfer coefficients of halogenated refrigerants up to critical heat fluxes

2009 ◽  
Vol 223 (6) ◽  
pp. 1415-1424 ◽  
Author(s):  
K-J Park ◽  
D Jung ◽  
S E Shim
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Nucleate Pool Boiling ◽  
Transfer Coefficients ◽  
Average Deviation ◽  
Heat Transfer Coefficients

In this work, nucleate pool boiling heat transfer coefficients (HTCs) of five refrigerants of differing vapour pressures are measured on a horizontal, smooth copper surface of 9.53×9.53 mm. The tested refrigerants are R123, R152a, R134a, R22, and R32 and HTCs are taken from 10 kW/m2 to the critical heat flux (CHF) of each refrigerant. Wall and fluid temperatures are measured directly by thermocouples located underneath the test surface and in the liquid pool, respectively. Test results show that nucleate pool boiling HTCs of halogenated refrigerants increase as the heat flux and vapour pressure increase. This typical trend is maintained even at high heat fluxes above 200 kW/m2. Zuber's prediction equation for CHF is quite accurate showing a maximum deviation of 21 per cent for all refrigerants tested. For all refrigerants, Stephan and Abdelsalam's well-known correlation underpredicted nucleate boiling HTC data up to the CHF with an average deviation of 21.3 per cent, while Cooper's correlation overpredicted the data with an average deviation of 14.2 per cent. On the other hand, Gorenflo's and Jung et al.'s correlations showed 5.8 and 6.4 per cent deviations, respectively, in the entire nucleate boiling range up to the CHF.

scholarly journals Developing a Mathematical Model for Nucleate Boiling Regime at High Heat Flux

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 726
Author(s):  
Mohd Danish ◽  
Mohammed Al Mesfer
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Close Agreement ◽  
Current Model ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
High Heat ◽  
High Heat Flux ◽  
Nucleate Pool Boiling ◽  
Wall Superheat

A mathematical model has been developed for heat exchange in nucleate boiling at high flux applying an energy balance on a macrolayer. The wall superheat, macrolayer thickness, and time are the parameters considered for predicting the heat flux. The influence of the wall superheat and macrolayer thickness on average heat flux has been predicted. The outcomes of the current model have been compared with Bhat’s constant macrolayer model, and it was found that these models are in close agreement corresponding to the nucleate pool boiling regime. It was concluded that the wall superheat and macrolayer thickness contributed significantly to conduction heat transfer. The average conduction heat fluxes predicted by the current model and by Bhat’s model are in close agreement for a thinner macrolayer of approximately 50 µm. For higher values of the wall superheat, which corresponds to the nucleate pool boiling condition, the predicted results strongly agree with the results of Bhat’s model. The findings also validate the claim that conduction across the macrolayer accounts for the main heat transfer mode from the heater surface to boiling liquid at high heat flux in nucleate pool boiling.

scholarly journals Nucleate pool boiling heat transfer: Review of models and bubble dynamics parameters

2021 ◽  
pp. 69-69
Author(s):  
Andrijana Stojanovic ◽  
Srdjan Belosevic ◽  
Nenad Crnomarkovic ◽  
Ivan Tomanovic ◽  
Aleksandar Milicevic
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Boiling Heat Transfer ◽  
Power Plants ◽  
Pool Boiling ◽  
Nucleation Site ◽  
Nucleate Pool Boiling ◽  
Numerical Work ◽  
Efficient Operation ◽  
Pool Boiling Heat Transfer

Understanding nucleate pool boiling heat transfer and, in particular the accurate prediction of conditions that can lead to critical heat flux, is of the utmost importance in many industries. Due to the safety issues related to the nuclear power plants, and for the efficient operation of many heat transfer units including fossil fuel boilers, fusion reactors, electronic chips, etc., it is important to understand this kind of heat transfer. In this paper, a comprehensive review of analytical and numerical work on nucleate pool boiling heat transfer is presented. In order to understand this phenomenon, existing studies on boiling heat transfer coefficient and boiling heat flux are also discussed, as well as characteristics of boiling phenomena such as bubble departure diameter, bubble departure frequency, active nucleation site density, bubble waiting and growth period and their impact on pool boiling heat transfer.

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