scholarly journals Experimental Study on Pool Boiling Heat Transfer Performance of Magnesium Oxide Nanoparticles Based Water Nanofluid

2020 ◽  
Vol 15 (3) ◽  
pp. 101-112
Author(s):  
Mohammed Saad Kamel ◽  
Ferenc Lezsovits
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Pool Boiling ◽  
Transfer Performance ◽  
Pool Boiling Heat Transfer ◽  
Magnesium Oxide Nanoparticles ◽  
Boiling Heat Transfer Coefficient

This study aims to experimentally investigate the nucleate pool boiling heat transfer performance of magnesium oxide nanoparticles MgO based deionized water nanofluid at the atmospheric pressure condition. Dilute volumetric concentrations within a range of 0.001% to 0.01% Vol. were used to examine the pool boiling heat transfer performance represented by pool boiling curve, and pool boiling heat transfer coefficient. The heating element was a horizontal copper heated tube with a typical diameter 22 mm submerged inside the cubic boiling chamber. Efforts have been made to measure the surface temperatures along the heated tube to ensure the proper and accurate heat transfer coefficient calculations in this work. The results indicated that the pool boiling heat transfer coefficient enhancement ratio (PBHTC /PBHTC ) was intensified for volume fractions i.e. 0.001%, 0.004%, and 0.007% Vol. while it was degraded for volume concentrations i.e. 0.01%, and 0.04% Vol. compared to deionized water as baseline case.

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.

Experimental and Numerical Study of Nucleate Pool Boiling Heat Transfer and Bubble Dynamics in Saline Solution

2020 ◽  
Author(s):  
Qi Liu ◽  
Yuxin Wu ◽  
Yang Zhang ◽  
Junfu Lyu
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Boiling Heat Transfer ◽  
Saline Solution ◽  
Numerical Study ◽  
Pool Boiling ◽  
Pool Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

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.

scholarly journals Experimental Investigation on Pool Boiling Heat Transfer Performance Using Tungsten Oxide WO3 Nanomaterial-Based Water Nanofluids

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1922 ◽  
Author(s):  
Mohammed Saad Kamel ◽  
Ferenc Lezsovits
Keyword(s):  
Heat Transfer ◽  
Tungsten Oxide ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Pool Boiling ◽  
Deionized Water ◽  
Transfer Performance ◽  
Pool Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

This study aims to experimentally investigate the pool boiling heat transfer coefficient behavior using tungsten oxide-based deionized water nanofluids and comparing them to deionized water as conventional fluid. The influence of different dilute volumetric concentrations (0.005%–0.05% Vol.) and applied heat fluxes were examined to see the effect of these parameters on the pool boiling heat transfer performance using nanofluids from a typical horizontal heated copper tube at atmospheric pressure conditions. Results demonstrated that the pool boiling heat transfer coefficient (PBHTC) for both deionized water and nanofluids increased with increasing the applied heat flux. The higher PBHTC enhancement ratio was 6.7% for a volume concentration of 0.01% Vol. at a low heat flux compared to the deionized water case. Moreover, the PBHTC for nanofluids was degraded compared to the deionized water case, and the maximum reduction ratio was about 15% for a volume concentration of 0.05% Vol. relative to the baseline case. The reduction in PBHTC was attributed to the deposition of tungsten oxide nanoflakes on the heating surface during the boiling process, which led to a decrease in the density of the nucleation sites.

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