Donald Q. Kern Lecture Award Paper: Odyssey of the Enhanced Boiling Surface

2004 ◽  
Vol 126 (6) ◽  
pp. 1051-1059 ◽  
Author(s):  
Ralph L. Webb
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Pore Diameter ◽  
Surface Geometry ◽  
Exchange System ◽  
Heat Exchange System ◽  
Fundamental Understanding ◽  
Boiling Heat Transfer Coefficient ◽  
Coated Surface ◽  
Enhanced Boiling

This paper traces the evolution of enhanced boiling surfaces. Early work was highly empirical and done in industrial research. The 1968 Milton patent [“Heat Exchange System,” U.S. Patent 3,696,861] described the first porous coated surface, and the 1972 Webb patent [“Heat Transfer Surface Having a High Boiling Heat Transfer Coefficient,” U.S. Patent 3,521,708] described a “structured” tube surface geometry. The first fundamental understanding of the “pore-and-tunnel” geometry was published by Nakayama in 1980 [Nakayama, W., Daikoku, T., Kuwahara, H., and Nakajima, T. 1980, “Dynamic Model of Enhanced Boiling Heat Transfer on Porous Surfaces Part I: Experimental Investigation,” J. Heat Transfer, 102, pp. 445–450]. Webb and Chien’s flow visualization allowed observation of the evaporation in the subsurface tunnels [Chien, L.-H., and Webb, R. L., 1998, “Visualization of Pool Boiling on Enhanced Surfaces,” Exp. Fluid Thermal Sci., 16b, pp. 332–341]. They also performed an experimental parametric study that defines the effect of pore diameter and pitch on the boiling performance. The progression of work on analytical boiling models is also reviewed.

Odyssey of the Enhanced Boiling Surface

Volume 4 ◽  
2004 ◽  
Author(s):  
Ralph L. Webb
Keyword(s):  
Flow Visualization ◽  
Parametric Study ◽  
Pore Diameter ◽  
Industrial Research ◽  
Tube Surface ◽  
Surface Geometry ◽  
Fundamental Understanding ◽  
Coated Surface ◽  
Enhanced Boiling

This paper traces the evolution of enhanced boiling surfaces. Early work was highly empirical and done in industrial research. The 1968 Milton patent described the first porous coated surface, and the 1971 Webb patent described a “structured” tube surface geometry. The first fundamental understanding of the “pore-and-tunnel” geometry was published by Nakayama in 1980. Webb and Chien’s flow visualization allowed observation of the evaporation in the sub-surface tunnels. They also performed an experimental parametric study that defines the effect of pore diameter and pitch on the boiling performance. The progression of work on analytical boiling models is also reviewed.

Heat Transfer Enhancement in Pool Boiling of Distilled Water Using Gridded Metal Surface With Protrusions Over Microporous-Coated Surface

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Vidushi Chauhan ◽  
Manoj Kumar ◽  
Anil Kumar Patil
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Metal Surface ◽  
Boiling Heat Transfer ◽  
Particle Diameter ◽  
Saturation Temperature ◽  
Grid Size ◽  
Boiling Heat Transfer Coefficient ◽  
Coated Surface

Abstract The nucleate pool is a useful technique of heat dissipation in a variety of thermal applications. This study investigates the effect of the gridded metal surface (GMS) with and without protrusions on the heat transfer from a surface maintained at a temperature above the saturation temperature of water. The experimental data have been collected pertaining to boiling heat transfer at atmospheric pressure by varying the grid size of gridded metal surface with protrusions from 6 mm to 22.5 mm placed over a boiling surface having microporous coating. The mean particle diameter of coating is varied as 11, 24, and 66 μm during the experimentation. It is observed that the increase in the boiling heat transfer coefficient of the aluminum disk with GMS with protrusions of grid size 11.5 mm compared to that of the smooth boiling surface is found to be 10.7%. Furthermore, the effect of GMS having protrusions with coated surface on the heat transfer is studied. The results showed that by using GMS having protrusions and with coated surface, the heat transfer is further enhanced. The boiling heat transfer coefficient obtained in case of GMS with protrusions (grid size = 11.5 mm) and microporous-coated surface (dm = 66 μm) shows the maximum enhancement of 39.93% in comparison to the smooth surface.

An Experimental Study of Boiling Heat Transfer on Mesh-Covered Fins

2009 ◽  
Author(s):  
Liang-Han Chien ◽  
H.-L. Huang
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Mesh Size ◽  
Wire Mesh ◽  
Finned Tubes ◽  
Enhanced Tubes ◽  
Boiling Heat Transfer Coefficient ◽  
Fin Tube ◽  
Enhanced Boiling ◽  
Fin Tubes

This study investigates a new enhanced boiling surface, which is made by wrapping wire mesh on finned tubes. Pool boiling performance of the new enhanced tubes has been tested in Refrigerant-134a at 5, 10, 20, and 26.67°C saturation temperatures. Brass or copper mesh of 80, 100, or 120 meshes per inch was wrapped on finned tubes of 42 or 60 FPI (fins per inch). The fin heights were either 0.2 mm or 0.4 mm. The test results show that the mesh covered fin tubes significantly enhanced the boiling performance by forming many pores of proper sizes on the surface and sustaining vapor in the tunnels formed by the mesh and fins. The preferred mesh size decreases with decreasing heat flux. The mesh covered on 60FPI fin tube having 0.4 mm fin height and 100 mesh per inch yields the best boiling performance. It enhances the boiling heat transfer coefficient by 7∼8 folds at 5°C as compared with the smooth tube.

Surface wettability effect of plain and plasma-sprayed copper-coated surfaces on CHF enhancement during saturated pool boiling of FC-72

2021 ◽  
pp. 095440622110574
Author(s):  
Rajiva Lochan Mohanty ◽  
Subhakanta Moharana ◽  
Mihir Kumar Das
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Coating Thickness ◽  
Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient ◽  
Coated Surface ◽  
Plain Surface ◽  
Coated Surfaces ◽  
Plasma Sprayed

In the current scenario, CHF study is essential for the safe operation of electronics equipment comprising a two-phase heat transfer process. Therefore, the present experimental investigation involves saturated pool boiling and CHF study of FC 72 over a plain stainless steel surface (SS) and microporous copper-coated SS surfaces under atmospheric conditions. Accordingly, three different plasma-sprayed copper-coated surfaces with coating thicknesses of 65 μm, 105 μm, and 145 μm prepared using micro copper particles of size 25–45 μm. The analysis of the results shows that with an increase in heat flux values, the boiling heat transfer coefficient increases over plain as well as coated surfaces. The plasma-spayed copper-coated surfaces with a coating thickness of 65 μm and 105 μm exhibit a higher boiling heat transfer coefficient as than the plain surface. On the other hand, a 145 μm thick coated surface resulted in a comparable boiling heat transfer coefficient with the plain SS surface. Among the three porous-coated surfaces, the boiling heat transfer coefficient decreases continuously from 65 μm to 145 μm of the coated surface. On the contrary, to the observed nucleate boiling behavior, all the porous-coated surfaces show a higher value of CHF than the plain surface, and the CHF value is found to increase continuously from 65 μm to 145 μm of the coated surfaces. The enhancement of CHF values was found to be 66.29%, 69.17%, and 77.75% for a coating thickness of 65 μm, 105 μm, and 145 μm, respectively, compared with the plain surface. The porous coating thickness of 65 μm shows a greater value of heat transfer coefficient than 105 μm and 145 μm whereas 145 μm exhibits a higher value of CHF as than 65 μm and 105 μm.

Numerical and Experimental Investigation Into the Effects of Nanoparticle Mass Fraction and Bubble Size on Boiling Heat Transfer of TiO2–Water Nanofluid

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Cong Qi ◽  
Yongliang Wan ◽  
Lin Liang ◽  
Zhonghao Rao ◽  
Yimin Li
Keyword(s):  
Heat Transfer ◽  
Bubble Size ◽  
Boiling Heat Transfer ◽  
Mass Fraction ◽  
Experimental Methods ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Mass Fractions ◽  
Boiling Heat Transfer Coefficient ◽  
Bubble Sizes

Considering mass transfer and energy transfer between liquid phase and vapor phase, a mixture model for boiling heat transfer of nanofluid is established. In addition, an experimental installation of boiling heat transfer is built. The boiling heat transfer of TiO2–water nanofluid is investigated by numerical and experimental methods, respectively. Thermal conductivity, viscosity, and boiling bubble size of TiO2–water nanofluid are experimentally investigated, and the effects of different nanoparticle mass fractions, bubble sizes and superheat on boiling heat transfer are also discussed. It is found that the boiling bubble size in TiO2–water nanofluid is only one-third of that in de-ionized water. It is also found that there is a critical nanoparticle mass fraction (wt.% = 2%) between enhancement and degradation for TiO2–water nanofluid. Compared with water, nanofluid enhances the boiling heat transfer coefficient by 77.7% when the nanoparticle mass fraction is lower than 2%, while it reduces the boiling heat transfer by 30.3% when the nanoparticle mass fraction is higher than 2%. The boiling heat transfer coefficients increase with the superheat for water and nanofluid. A mathematic correlation between heat flux and superheat is obtained in this paper.

Visualization of Boiling Heat Transfer on Micro Porous Coated Surface in Confined Space

2013 ◽  
Author(s):  
Chien-Yuh Yang ◽  
Chien-Fu Liu
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Heating Surface ◽  
Nucleate Boiling ◽  
Confined Space ◽  
Two Phase ◽  
Nucleate Boiling Heat Transfer ◽  
Coated Surface

Numerous researches have been developed for pool boiling on microporous coated surface in the past decade. The nucleate boiling heat transfer was found to be increased by up to 4.5 times than that on uncoated surface. Recently, the two-phase micro heat exchangers have been considered for high flux electronic devices cooling. The enhancement techniques for improving the nucleate boiling heat transfer performance in the micro heat exchangers have gotten more importance. Previous studies of microporous coatings, however, have been restricted to boiling in unconfined space. No studies have been made on the feasibility of using microporous coatings for enhancing boiling in confined spaces. This study provides an experimental observation of the vapor generation and leaving processes on microporous coatings surface in a 1-mm confined space. It would be helpful for understanding the mechanism of boiling heat transfer and improving the design of two-phase micro heat exchangers. Aluminum particles of average diameter 20 μm were mixed with a binder and a carrier to develop a 150 μm thickness boiling enhancement paint on a 3.0 cm by 3.0 cm copper heating surface. The heating surface was covered by a thin glass plate with a 1 mm spacer to form a 1 mm vertical narrow space for the test section. The boiling phenomenon was recorded by a high speed camera. In addition to the three boiling regimes observed by Bonjour and Lallemand [1], i.e., isolated deformed bubbles, coalesced bubbles and partial dryout at low, moderate and high heat fluxes respectively in unconfined space, a suction and blowing process was observed at the highest heat flux condition. Owing to the space confinement, liquid was sucked and vapor was expelled periodically during the bubble generation process. This mechanism significantly enhanced the boiling heat transfer performance in confined space.

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%.

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