Pool boiling heat transfer to cryogenic liquids; III. Nucleate boiling data and peak nucleate boiling fluxes for Nitrogen-Oxygen mixtures

AIChE Journal ◽  
1968 ◽  
Vol 14 (3) ◽  
pp. 383-387
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Pool Boiling Heat Transfer ◽  
Cryogenic Liquids

Pool Boiling Heat Transfer with Nanotube Arrays Surface on Titanium

2012 ◽  
Vol 550-553 ◽  
pp. 2913-2916 ◽  
Author(s):  
Jin Liang Tao ◽  
Xin Liang Wang ◽  
Pei Hua Shi ◽  
Xiao Ping Shi
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Test Fluid ◽  
Porous Coating ◽  
Pool Boiling Heat Transfer ◽  
Nucleate Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient

In this paper, a new porous coating was formed directly on the surface of titanium metal via anodic oxidation. And by the SEM, the morphology of the coating, which is composed of well-ordered perpendicular nanotubes, was characterized. Moreover, taking deionized water as the test fluid, a visualization study of the coating on its pool boiling heat transfer performance was made. The results demonstrated that compared with the smooth surface, the nucleate boiling heat transfer coefficient can increase 3 times while the nucleate boiling super heat was reduced 30%.

Nucleate Boiling on Biotemplated Nanostructured Surfaces

2012 ◽  
Author(s):  
Md. Mahamudur Rahman ◽  
Stephen M. King ◽  
Emre Olceroglu ◽  
Matthew McCarthy
Keyword(s):  
Heat Transfer ◽  
Self Assembly ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Pool Boiling Heat Transfer ◽  
Nanostructured Surfaces ◽  
Transfer Capability ◽  
Good Agreement

The fabrication and characterization of biotemplated nanostructured surfaces for enhanced pool boiling heat transfer is reported. By introducing micro/nano-porosity and surface roughness at the liquid-vapor interface, significant enhancement in surface heat transfer capability can be achieved during nucleate boiling. This work uses the self-assembly and mineralization of the Tobacco mosaic virus (TMV) to create superhydrophilic (∼9°), superhydrophobic (∼163°), and mixed hydrophilic-hydrophobic (∼70°) surfaces to investigate the effects of surface wettability and heterogeneity on boiling heat transfer performance. Pool boiling results showing CHF and HTC values for nickel-coated TMV, Teflon-coated TMV, mixed nickel + Teflon coated TMV, flat silicon, and flat Teflon are reported. The mixed surfaces demonstrate a CHF enhancement of ∼ 70% compared to flat silicon and ∼140% compared to flat Teflon. The results are in good agreement with the literature and will guide the design of optimized surfaces for further enhancement. This work demonstrates the feasibility of enhancing pool boiling heat transfer using TMV based nanostructured coatings.

scholarly journals Effect of Subcooling on Pool Boiling of Water from Sintered Copper Microporous Coating at Different Orientations

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Seongchul Jun ◽  
Jinsub Kim ◽  
Seung M. You ◽  
Hwan Yeol Kim
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Average Particle Size ◽  
Nucleate Boiling ◽  
Copper Surface ◽  
Average Particle ◽  
Pool Boiling Heat Transfer ◽  
Microporous Coating ◽  
Plain Surface

The subcooling effect on pool boiling heat transfer using a copper microporous coating was experimentally studied in water for subcoolings of 10 K, 20 K, and 30 K at atmospheric pressure and compared to that of a plain copper surface. A high-temperature thermally conductive microporous coating (HTCMC) was made by sintering copper powder with an average particle size of 67 μm onto a 1 cm × 1 cm plain copper surface with a coating thickness of ~300 μm. The HTCMC surface showed a two times higher critical heat flux (CHF), ~2,000 kW/m2, and up to seven times higher nucleate boiling heat transfer (NBHT) coefficient, ~350 kW/m2K, when compared with a plain copper surface at saturation. The results of the subcooling effect on pool boiling showed that the NBHT of both the HTCMC and the plain copper surface did not change much with subcooling. On the other hand, the CHF increased linearly with the degree of subcooling for both the HTCMC and the plain copper surface. The increase in the CHF was measured to be ~60 kW/m2for every degree of subcooling for both the HTCMC and the plain surface, so that the difference of the CHF between the HTCMC and the plain copper surface was maintained at ~1,000 kW/m2throughout the tested subcooling range. The CHFs for the HTCMC and the plain copper surface at 30 K subcooling were 3,820 kW/m2and 2,820 kW/m2, respectively. The experimental results were compared with existing CHF correlations and appeared to match well with Zuber’s formula for the plain surface. The combined effect of subcooling and orientation of the HTCMC on pool boiling heat transfer was studied as well.

scholarly journals Pool Boiling Amelioration by Aqueous Dispersion of Silica Nanoparticles

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2138
Author(s):  
Sayantan Mukherjee ◽  
Naser Ali ◽  
Nawaf F. Aljuwayhel ◽  
Purna C. Mishra ◽  
Swarnendu Sen ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Contact Angle ◽  
Boiling Heat Transfer ◽  
Base Fluid ◽  
Bubble Diameter ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Surface Wettability ◽  
Bulk Fluid ◽  
Pool Boiling Heat Transfer

Non-metallic oxide nanofluids have recently attracted interest in pool boiling heat transfer (PBHT) studies. Research work on carbon and silica-based nanofluids is now being reported frequently by scholars. The majority of these research studies showed improvement in PBHT performance. The present study reports an investigation on the PBHT characteristics and performance of water-based silica nanofluids in the nucleate boiling region. Sonication-aided stable silica nanofluids with 0.0001, 0.001, 0.01, and 0.1 particle concentrations were prepared. The stability of nanofluids was detected and confirmed via visible light absorbance and zeta potential analyses. The PBHT performance of nanofluids was examined in a customized boiling pool with a flat heating surface. The boiling characteristics, pool boiling heat transfer coefficient (PBHTC), and critical heat flux (CHF) were analyzed. The effects of surface wettability, contact angle, and surface roughness on heat transfer performance were investigated. Bubble diameter and bubble departure frequency were estimated using experimental results. PBHTC and CHF of water have shown an increase due to the nanoparticle inclusion, where they have reached a maximum improvement of ≈1.33 times over that of the base fluid. The surface wettability of nanofluids was also enhanced due to a decrease in boiling surface contact angle from 74.1° to 48.5°. The roughness of the boiling surface was reduced up to 1.5 times compared to the base fluid, which was due to the nanoparticle deposition on the boiling surface. Such deposition reduces the active nucleation sites and increases the thermal resistance between the boiling surface and bulk fluid layer. The presence of the dispersed nanoparticles caused a lower bubble departure frequency by 2.17% and an increase in bubble diameter by 4.48%, which vigorously affects the pool boiling performance.

Influence of Surface Wettability on Pool Boiling Heat Transfer

2009 ◽  
Author(s):  
Hai Trieu Phan ◽  
Nadia Caney ◽  
Philippe Marty ◽  
Stephane Colasson ◽  
Je´roˆme Gavillet ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Contact Angles ◽  
Surface Wettability ◽  
Water Contact ◽  
Pool Boiling Heat Transfer ◽  
Nucleate Boiling Heat Transfer ◽  
Classical Models

Although boiling process has been a major subject of research for several decades, its physics still remain unclear and require further investigation. This study aims at highlighting the effects of the surface wettability on pool boiling heat transfer. Nanocoating techniques were used to vary the water contact angle from 20 to 110° by modifying nanoscale surface topography and chemistry. The experimental results obtained disagree with the predictions of the classical models. A new approach of nucleation mechanism is established to clarify the nexus between the surface wettability and the nucleate boiling heat transfer. In this approach, we introduce the concept of macro- and micro-contact angles to explain the observed phenomenon.

EHD-Enhanced Boiling Coefficients and Visualization of R-134a Over Enhanced Tubes

1997 ◽  
Vol 119 (2) ◽  
pp. 332-338 ◽  
Author(s):  
K. Cheung ◽  
M. M. Ohadi ◽  
S. Dessiatoun ◽  
A. Singh
Keyword(s):  
Heat Transfer ◽  
Flow Visualization ◽  
Boiling Heat Transfer ◽  
Tube Bundle ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Transfer Coefficients ◽  
Surface Geometry ◽  
Pool Boiling Heat Transfer ◽  
R 134A

In an earlier study by the authors, the applicability of the EHD technique for augmentation of pool boiling heat transfer of R-134a in a tube bundle was demonstrated. This paper reports additional experiments involving optimization of the electrode/heat transfer surface geometry as well as flow visualization studies that provide improved understanding of the EHD-enhanced pool boiling heat transfer in a tube bundle. Utilizing the flow visualization studies, it is demonstrated that combined electroconvection and improved nucleate boiling dynamics give rise to the augmented heat transfer coefficients.

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