The Enhancement of Pool Boiling Heat Transfer by Passive Technique using Rotating Blades Applied on the Nucleation Sites

Abstract The manipulation of micro- or nano-structure is a promising method to improve pool boiling heat transfer performance. However, most studies just focus on the micro- or nano-structure without considering the combination micro- and nano-structure. In this paper, we fabricated synergistic microchannel, nano-structure, and micro-nano structure surface on the nickel by different technologies. Pool boiling of DI water under saturated condition was experimentally investigated. Result shows at the wall superheat of 18 K, the heat transfer coefficient of micro-nano structure, nano-structure and synergistic micro-channel surface are 16400, 13050, and 13400 W/m2 K higher 89%, 50%, and 54% than that of smooth surface, respectively. The improved heat transfer is attributed to active nucleation sites and capillary flow.

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Study of pool boiling heat transfer with FC-72 on open microchannel surfaces

EPJ Web of Conferences ◽

10.1051/epjconf/201921302038 ◽

2019 ◽

Vol 213 ◽

pp. 02038

Author(s):

Robert Kaniowski ◽

Robert Pastuszko ◽

Milena Bedla-Pawlusek ◽

Łukasz Nowakowski

Keyword(s):

Heat Transfer ◽

Boiling Heat Transfer ◽

Pool Boiling ◽

Fold Increase ◽

Transfer Coefficients ◽

Pool Boiling Heat Transfer ◽

Heat Transfer Coefficients ◽

Nucleation Sites ◽

Open Microchannel ◽

Parallel Microchannels

The paper presents investigations into pool boiling heat transfer for open microchannel surfaces. The experiments were carried out with saturated FC-72 at atmospheric pressure. Parallel microchannels fabricated by machining were about 0.2 to 0.4 mm wide and 0.2 to 0.5 mm deep. Analyzed surfaces with microchannels allowed to obtain heat transfer coefficients within the range of 6.1 – 9.8 kW/m2K, which in relation to the flat surface gives a 3 – 5 - fold increase in HTC. One of the reasons for the increase in the heat transfer coefficient when increasing the heat flux was the growing number of active nucleation sites at the bottom of microchannels and its side surfaces.

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SIZE DISTRIBUTIONS OF ACTIVE NUCLEATION SITES WITH POOL BOILING HEAT TRANSFER AT SINGLE TUBES WITH DIFFERENT ROUGHNESSES

Proceeding of International Heat Transfer Conference 10 ◽

10.1615/ihtc10.4580 ◽

1994 ◽

Cited By ~ 6

Author(s):

Heiko Schomann ◽

Andrea Luke ◽

Dieter Gorenflo

Keyword(s):

Heat Transfer ◽

Boiling Heat Transfer ◽

Pool Boiling ◽

Size Distributions ◽

Pool Boiling Heat Transfer ◽

Nucleation Sites

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A Fractal Model for Nucleate Pool Boiling Heat Transfer

Journal of Heat Transfer ◽

10.1115/1.1513580 ◽

2002 ◽

Vol 124 (6) ◽

pp. 1117-1124 ◽

Cited By ~ 36

Author(s):

Boming Yu ◽

Ping Cheng

Keyword(s):

Heat Transfer ◽

Experimental Data ◽

Fractal Dimension ◽

Boiling Heat Transfer ◽

Pool Boiling ◽

Fractal Model ◽

Nucleate Pool Boiling ◽

Pool Boiling Heat Transfer ◽

Wall Superheat ◽

Nucleation Sites

In this paper, a fractal model for nucleate pool boiling heat transfer is developed based on the fractal distribution of sites (areas) of nucleation sites on boiling surfaces. Algebraic expressions for the fractal dimension and area fraction of nucleation sites are derived, which are shown to be a strong function of wall superheat. The predicted fractal dimension is shown in good agreement with those determined by the box-counting method. The fractal model for nucleate boiling heat transfer is found to be a function of wall superheat, the contact angle of the fluid and the heater material, and physical properties of the fluid with a minimum number of empirical constants. The predicted total heat flux from a boiling surface based on the present fractal model is compared with existing experimental data. An excellent agreement between the model predictions and experimental data is found, which verifies the validity of the present fractal model.

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