EFFECT OF THE SURFACE ROUGHNESS ON THE NUCLEATE BOILING HEAT TRANSFER OVER THE WIDE RANGE OF PRESSURE

1982 ◽  
Author(s):  
Kaneyasu Nishikawa ◽  
Yasunobu Fujita ◽  
Haruhiko Ohta ◽  
Sumitomo Hidaka
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Wide Range ◽  
Nucleate Boiling Heat Transfer

scholarly journals Micro-Nano Scale Surface Coating for Nucleate Boiling Heat Transfer: A Critical Review

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3189 ◽  
Author(s):  
Shoukat Khan ◽  
Muataz Atieh ◽  
Muammer Koç
Keyword(s):  
Heat Transfer ◽  
Surface Coating ◽  
Boiling Heat Transfer ◽  
Waste Heat ◽  
Material Selection ◽  
Nucleate Boiling ◽  
Surface Geometry ◽  
Nano Scale ◽  
Wide Range ◽  
Nucleate Boiling Heat Transfer

Nucleate boiling is a phase change heat transfer process with a wide range of applications i.e., steam power plants, thermal desalination, heat pipes, domestic heating and cooling, refrigeration and air-conditioning, electronic cooling, cooling of turbo-machinery, waste heat recovery and much more. Due to its quite broad range of applications, any improvement in this area leads to significant economic, environmental and energy efficiency outcomes. This paper presents a comprehensive review and critical analysis on the recent developments in the area of micro-nano scale coating technologies, materials, and their applications for modification of surface geometry and chemistry, which play an important role in the enhancement of nucleate boiling heat transfer. In many industrial applications boiling is a surface phenomenon, which depends upon its variables such as surface area, thermal conductivity, wettability, porosity, and roughness. Compared to subtractive methods, the surface coating is more versatile in material selection, simple, quick, robust in implementation and is quite functional to apply to already installed systems. The present status of these techniques for boiling heat transfer enhancement, along with their future challenges, enhancement potentials, limitations, and their possible industrial implementation are also discussed in this paper.

Surface Modifications Using Nanofluids for Nucleate Boiling Heat Transfer and CHF Enhancements

2008 ◽  
Author(s):  
Bao Truong ◽  
Lin-Wen Hu ◽  
Jacopo Buongiorno
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Roughness ◽  
Critical Heat Flux ◽  
Boiling Heat Transfer ◽  
Surface Modifications ◽  
Nucleate Boiling ◽  
Colloidal Dispersions ◽  
Enhancement Mechanism ◽  
Nucleate Boiling Heat Transfer

Colloidal dispersions of nanoparticles, also known as nanofluids, have shown to result in significant Critical Heat Flux (CHF) enhancement. The CHF enhancement mechanism in nanofluids is due to the buildup of a layer of nanoparticles which occurs upon boiling. Some studies have shown that this layer may also lead to increase in nucleate boiling heat transfer. Therefore, this paper discusses how key surface parameters such as surface wettability and surface roughness can be manipulated and optimized by coating nanoparticles in colloidal dispersions onto the desired surface, to enhance the nucleate boiling heat transfer and CHF.

An Overview: Analysis of Heat and Mass Transfer in Fractal Media by Fractal Geometry and Technique

2010 ◽  
Author(s):  
Boming Yu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Porous Media ◽  
Heat And Mass Transfer ◽  
Oil Recovery ◽  
Fractal Geometry ◽  
Boiling Heat Transfer ◽  
Nucleate Boiling ◽  
Fractal Media ◽  
Nucleate Boiling Heat Transfer

In the past three decades, fractal geometry and technique have received considerable attention due to its wide applications in sciences and technologies such as in physics, mathematics, geophysics, oil recovery, material science and engineering, flow and heat and mass transfer in porous media etc. The fractal geometry and technique may become particularly powerful when they are applied to deal with random and disordered media such as porous media, nanofluids, nucleate boiling heat transfer. In this paper, a summary of recent advances is presented in the areas of heat and mass transfer in fractal media by fractal geometry technique. The present overview includes a brief summary of the fractal geometry technique applied in the areas of heat and mass transfer; thermal conductivities of porous media and nanofluids; nucleate boiling heat transfer. A few comments are made with respect to the theoretical studies that should be made in the future.

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.

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