The Hoodoo: A New Surface Structure for Enhanced Boiling Heat Transfer

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Bradley Bon ◽  
James F. Klausner ◽  
Edward Mckenna
Keyword(s):  
Heat Transfer ◽  
Surface Structure ◽  
Boiling Heat Transfer ◽  
Enhancement Factor ◽  
Smooth Surface ◽  
Nucleation Site ◽  
Transfer Enhancement ◽  
Droplet Spreading ◽  
Primary Mechanism ◽  
Enhanced Boiling

The hoodoo is introduced as a beneficial surface structure for enhancing boiling heat transfer. A full parametric study was conducted to determine which attributes of the hoodoo structure promote boiling heat transfer enhancement. Hoodoo size and spacing were observed to have the most profound effect on boiling heat transfer, nucleation site activation, and critical heat flux (CHF). The CHF enhancement factor, defined as the ratio of CHF on the structured surface to that of a smooth surface, varies from 1.05 to 1.67 for FC-72 and hexane working fluids. Droplet spreading studies confirm the hemiwicking properties of the hoodoo surface, and it is postulated to be the primary mechanism for CHF enhancement. Measured wicking front speeds varied from 12 to 40 mm/s and were observed to obey a power-law dependence on time with an exponent of approximately 0.5. Plausible thermohydraulic mechanisms for CHF enhancement on the hoodoo surfaces are discussed.

Creation of Nano-Scaled Surface Structure for the Enhancement of Boiling Heat Transfer

2004 ◽  
Author(s):  
Sho Ngai ◽  
A. I. Leontiev ◽  
John R. Lloyd ◽  
S. P. Malyshenko
Keyword(s):  
Heat Transfer ◽  
Boiling Heat Transfer ◽  
Nucleation Site ◽  
Glancing Angle Deposition ◽  
Surface Structures ◽  
Transfer Enhancement ◽  
Site Density ◽  
Glancing Angle ◽  
Angle Deposition ◽  
Nucleation Site Density

The present research is an experimental investigation of nucleate pool boiling heat transfer enhancement on a surface with micro/nano-scaled surface structures. Glancing Angle Deposition (GLAD) was employed to fabricate porous surfaces in this study. The thin film microstructure consists of closely packed columns oriented in the plane of incidence formed due to a self-shadowing mechanism. Boiling heat transfer from the nano-structured surface was compared to that of a smooth reference surface and the commercial High Flux surface. The results of this study have shown that nano-structured films created by the GLAD process increase the nucleation site density as compared to the smooth surface. This research has opened up new areas in the field of heat transfer, which motivate new surface coating concepts to enhance the understanding of boiling heat transfer on nano-structured films.

Pool Boiling Heat Transfer of N-Pentane and Acetone on Nanostructured Surfaces by Electrophoretic Deposition

2018 ◽  
Author(s):  
Zan Wu ◽  
Anh Duc Pham ◽  
Zhen Cao ◽  
Cathrine Alber ◽  
Peter Falkman ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Electrophoretic Deposition ◽  
Boiling Heat Transfer ◽  
Smooth Surface ◽  
Pool Boiling ◽  
Nucleation Site ◽  
Working Fluids ◽  
Pool Boiling Heat Transfer ◽  
Nanostructured Surfaces ◽  
Coated Surfaces

This work aims to investigate pool boiling heat transfer enhancement by using nanostructured surfaces. Two types of nanostructured surfaces were employed, gold nanoparticle-coated surfaces and alumina nanoparticle-coated surfaces. The nanostructured surfaces were fabricated by an electrophoretic deposition technique, depositing nanoparticles in a nanofluid onto smooth copper surfaces under an electric field. N-pentane and acetone were tested as working fluids. Compared to the smooth surface, the pool boiling heat transfer coefficient has been increased by 80% for n-pentane and acetone. Possible mechanisms for the enhancement in heat transfer are qualitatively provided. The increase in active nucleation site density due to multiple micro/nanopores on nanoparticle-coated surfaces is likely the main contributor. The critical heat flux on nanostructured surfaces are approximately the same as that on the smooth surface because both smooth and modified surfaces show similar wickability for the two working fluids.

HEAT TRANSFER ENHANCEMENT IN PHASE-CHANGE HEAT EXCHANGERS

Aviation ◽  
2014 ◽  
Vol 18 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Rafał Chatys ◽  
Milan Malcho ◽  
Łukasz J. Orman
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Atmospheric Pressure ◽  
Heat Exchangers ◽  
Boiling Heat Transfer ◽  
Smooth Surface ◽  
Transfer Enhancement ◽  
Mesh Structure ◽  
Heat Exchanger Surface ◽  
Copper Mesh

The paper presents the results of boiling heat transfer enhancement due to the application of additional mesh on the heat exchanger surface. The copper mesh of porosity of 75% was sintered to the copper heater producing strong bonds between the elements. The results indicate a possibility of significant improvement of heat transfer conditions in comparison to the smooth surface. The heat flux was found to be almost six times higher for the same superheat if the mesh structure was applied. Distilled water and ethanol were the working fluids. The investigations were performed under atmospheric pressure.

Boiling heat transfer enhancement of nanofluids on a smooth surface with agitation

2016 ◽  
Vol 52 (12) ◽  
pp. 2769-2780 ◽  
Author(s):  
Xin Kong ◽  
Baojin Qi ◽  
Jinjia Wei ◽  
Wei Li ◽  
Jie Ding ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Boiling Heat Transfer ◽  
Smooth Surface ◽  
Transfer Enhancement
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