Comparisons of Aqueous Surfactant Solutions for Nucleate Pool Boiling

2016 ◽  
Author(s):  
Birce Dikici ◽  
Basim Q. A. Al-Sukaini
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pure Water ◽  
Pool Boiling ◽  
Lauryl Sulfate ◽  
Nucleate Pool Boiling ◽  
Transfer Enhancement ◽  
Surfactant Solutions ◽  
Boiling Heat Transfer Coefficient ◽  
Important Possibility

In this study, nucleate pool boiling of surfactant solutions are investigated. The surfactants chosen for the study are an ionic sodium lauryl sulfate (SLS), nonionic ECOSURF™ EH-14, and nonionic ECOSURF™ SA-9. It is observed that adding a small amount of surfactant alters the water boiling phenomenon considerably. Boiling curves for different concentrations are shifted to the left. The wall temperature dropped with an increase in the concentration of aqueous surfactant solutions. Also, it is found that the boiling heat transfer enhancement of SLS is higher than that of EH-14 and SA-9 compared to water. Boiling heat transfer coefficient (h) enhancements compared to water are 46%, 30%, and 21%. (for SLS, for EH-14 and for SA-9 respectively) Boiling visualization shows that boiling with surfactant solutions compared with that in pure water is more vigorous. Bubbles are smaller, activate continuously, and collapse quickly. Also, the bubble departure frequency is observed to be higher than that of pure water. Results prove that there is an important possibility to enhance the boiling application processes by environmentally friendly EH-14, and SA-9 additives. Experimentation can be extended for searching other surfactants in order to find their most efficient quantity in water for boiling heat transfer.

scholarly journals Quantitative Evaluation of the Dependence of Pool Boiling Heat Transfer Enhancement on Sintered Particle Coating Characteristics

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Suchismita Sarangi ◽  
Justin A. Weibel ◽  
Suresh V. Garimella
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Transfer Enhancement ◽  
Pool Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient ◽  
Coating Characteristics

Immersion cooling strategies often employ surface enhancements to improve the pool boiling heat transfer performance. Sintered particle/powder coatings have been commonly used on smooth surfaces to reduce the wall superheat and increase the critical heat flux (CHF). However, there is no unified understanding of the role of coating characteristics on pool boiling heat transfer enhancement. The morphology and size of the particles affect the pore geometry, permeability, thermal conductivity, and other characteristics of the sintered coating. In turn, these characteristics impact the heat transfer coefficient and CHF during boiling. In this study, pool boiling of FC-72 is experimentally investigated using copper surfaces coated with a layer of sintered copper particles of irregular and spherical morphologies for a range of porosities (∼40–80%). Particles of the same effective diameter (90–106 μm) are sintered to yield identical coating thicknesses (∼4 particle diameters). The porous structure formed by sintering is characterized using microcomputed tomography (μ-CT) scanning to study the geometric and effective thermophysical properties of the coatings. The boiling performance of the porous coatings is analyzed. Coating characteristics that influence the boiling heat transfer coefficient and CHF are identified and their relative strength of dependence analyzed using regression analysis. Irregular particles yield higher heat transfer coefficients compared to spherical particles at similar porosity. The coating porosity, pore diameter, unit necking area, unit interfacial area, effective thermal conductivity, and effective permeability are observed to be the most critical coating properties affecting the boiling heat transfer coefficient and CHF.

scholarly journals Prediction of nucleate pool boiling heat transfer coefficient

2010 ◽  
Vol 14 (2) ◽  
pp. 353-364 ◽  
Author(s):  
Alangar Sathyabhama ◽  
Ramakrishna Hegde
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Correct Prediction ◽  
Nucleate Pool Boiling ◽  
Successful Operation ◽  
Refrigeration Unit ◽  
Boiling Heat Transfer Coefficient

The correct prediction of the heat transfer performance of the boiling liquid within the evaporator of a refrigeration unit is one of the essential features for the successful operation of the whole unit. There are many correlations available in the literature for the prediction of boiling heat transfer coefficient of pure components. Eight heat transfer pool-boiling correlations that are well known in the literature have been selected and their prediction accuracy has been assessed against experimental data of ammonia available in the literature. The analysis concludes that within the investigated ranges of boiling conditions, the Kruzhilin, Kutateladze, Labuntsov, Mostinski nucleate pool-boiling correlations are the most accurate among those assessed.

Investigation on the Effect of Type and Size of Nanoparticles and Surfactant on Pool Boiling Heat Transfer of Nanofluids

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Tofigh Sayahi ◽  
Masoud Bahrami
Keyword(s):  
Heat Transfer ◽  
Zinc Oxide ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Pure Water ◽  
Pool Boiling ◽  
Heat Removal ◽  
Pool Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

In our efforts to improve the pool boiling heat transfer of water, three sets of experiments are carried out to investigate the best coolant for heat removal among alumina, silica, and zinc oxide as nanoparticles and water as base fluid: (a) pool boiling heat transfer of γ-alumina/water nanofluid with and without surfactant in both distilled water and treated water as base fluids, (b) pool boiling heat transfer of silica/water nanofluid with two different nanoparticle sizes, and (c) pool boiling heat transfer of zinc oxide/water nanofluid with surfactant. In all the above experiments, the effect of heater surface on boiling heat transfer coefficient has been investigated by repeating the experiment using pure water on the coated surface before cleaning it. Moreover, two effective thermophysical properties of fluids, dynamic viscosity and surface tension, are measured to explain the boiling behavior of the nanofluids. The experimental results indicate that (a) the presence of γ-alumina in the base fluid enhances the pool boiling heat transfer coefficient, but sodium dodecyl sulphate (SDS) as surfactant deteriorates the performance of pool boiling heat transfer of γ-alumina/water nanofluid and (b) silica nanoparticles reduce the boiling performance of pure water. Moreover, the larger particle size of silica nanoparticles shows less reduction in heat transfer coefficient, (c) zinc oxide/water nanofluid is the best coolant among all the above-mentioned nanoparticles for heat removal.

scholarly journals Experimental studies on nucleate pool boiling heat transfer to ethanol/MEG/DEG ternary mixture as a new coolant

2012 ◽  
Vol 18 (4-1) ◽  
pp. 577-586 ◽  
Author(s):  
M.M. Sarafraz ◽  
S.M. Peyghambarzadeh ◽  
Alavi Fazel
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Ternary Mixture ◽  
Pool Boiling ◽  
Heat Fluxes ◽  
Nucleate Pool Boiling ◽  
Pool Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

In this paper, nucleate pool boiling heat transfer coefficient of ternary mixtures of ethanol, monoethylene glycol (MEG) and diethylene glycol (DEG) as a new coolant with higher heat transfer coefficient has been investigated. Therefore, at varied concentrations of MEG and DEG and also at different heat fluxes, pool boiling heat transfer coefficients, have been experimentally measured. Results demonstrated the higher heat transfer coefficient in comparison with Water/MEG/DEG ternary mixture. In particular, at high heat fluxes, for ethanol/MEG/DEG mixture, higher boiling heat transfer coefficient is reported. Besides, experimental data were compared to well-known existing correlations. Results of this comparison express that the most accurate correlation for predicting the heat transfer coefficient of ethanol/MEG/DEG is modified Stephan - Preu?er which has been obtained in our earlier work.

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