CHF enhancement of downward-facing saturated pool boiling on the SCGS-modified surfaces with multi-scale conical pin fin structures

Saturated pool boiling heat transfer of water is investigated experimentally on copper surfaces with nanoparticle coatings at atmospheric pressure. The coatings are generated by an electrophoretic deposition method (EPD). Three modified surfaces are prepared with gold nanoparticles of 0.20 mg, 0.25 mg and 0.30 mg, respectively. During the deposition, ethanol works as the solvent while the electrical potential and deposition time are controlled as 9.5 V and 30 min, respectively. The experimental results show that heat transfer coefficients (HTC) and critical heat fluxes (CHF) are enhanced on the modified surfaces. HTC increases with decreasing thickness of the coating, while CHF increases with increasing thickness of the coating. CHFs of EPD-0.20 mg, EPD-0.25 mg and EPD-0.30 mg are 93 W/cm2, 123 W/cm2 and 142 W/cm2, respectively, which are increased by 7%, 41% and 63% compared with the smooth surface. EPD-0.20 mg performs the best on heat transfer, with a maximum enhancement of around 60%. At the end, a brief review about mechanistic models of heat transfer at low and moderate heat fluxes is provided, based on which, the reasons why heat transfer is enhanced are discussed.

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A Systematic Study of Pool Boiling Heat Transfer on Multiscale Structured Surfaces

Volume 8B: Heat Transfer and Thermal Engineering ◽

10.1115/imece2014-36236 ◽

2014 ◽

Cited By ~ 1

Author(s):

Russell P. Rioux ◽

Eric C. Nolan ◽

Calvin H. Li

Keyword(s):

Heat Transfer ◽

Boiling Heat Transfer ◽

Multiple Scales ◽

Pool Boiling ◽

Theoretical Models ◽

Sintering Process ◽

Structured Surfaces ◽

Pool Boiling Heat Transfer ◽

Nanostructured Surfaces ◽

Modified Surfaces

A study has been conducted to examine the effects of macroscale, microscale, and nanoscale surface modifications in water pool boiling heat transfer and to determine the effects of combining the multiple scales. Nanostructured surfaces were created by acid etching, while microscale and macroscale surfaces were manufactured through a sintering process. Six structures were studied as individual and/or collectively integrated surfaces: polished plain, flat nanostructured, flat porous, modulated porous, nanostructured flat porous, and nanostructured modulated porous. Boiling performance was measured in terms of critical heat flux (CHF) and heat transfer coefficient (HTC). Both HTC and CHF have been greatly improved on all modified surfaces compared to the polished baseline. The CHF and HTC of the hybrid multiscale modulated porous surface have achieved the most significant improvements of 350% and 200% over the polished plain surface, respectively. Nanoscale, microscale, and macroscale integrated surfaces have been proven to have the most significant improvements on HTC and CHF. Experimental results were compared to the predictions of a variety of theoretical models with an attempt to evaluate both microscale and nanoscale models. It was concluded that models for both microscale and nanoscale structured surfaces needed to be further developed to be able to have good quantitative predictions of CHFs on structured surfaces.

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Effect of modified surfaces on bubble dynamics and pool boiling heat transfer enhancement: A review

Thermal Science and Engineering Progress ◽

10.1016/j.tsep.2019.100451 ◽

2020 ◽

Vol 15 ◽

pp. 100451 ◽

Cited By ~ 5

Author(s):

Afsaneh Mehralizadeh ◽

Seyed Reza Shabanian ◽

Gholamreza Bakeri

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Boiling Heat Transfer ◽

Bubble Dynamics ◽

Pool Boiling ◽

Transfer Enhancement ◽

Pool Boiling Heat Transfer ◽

Modified Surfaces

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ENHANCEMENT OF POOL BOILING HEAT TRANSFER WITH PIN-FIN MICROSTRUCTURES

Journal of Enhanced Heat Transfer ◽

10.1615/jenhheattransf.2017019452 ◽

2016 ◽

Vol 23 (2) ◽

pp. 137-153 ◽

Cited By ~ 4

Author(s):

Lukasz Orman

Keyword(s):

Heat Transfer ◽

Boiling Heat Transfer ◽

Pool Boiling ◽

Pool Boiling Heat Transfer ◽

Pin Fin

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Pool Boiling CHF Enhancement on a Zircaloy-4 Surface With Micro/Nano Scale Modification

ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer, Volume 1 ◽

10.1115/mnhmt2009-18311 ◽

2009 ◽

Author(s):

Ho Seon Ahn ◽

Chan Lee ◽

Hyungdae Kim ◽

Hang Jin Jo ◽

Soon Ho Kang ◽

...

Keyword(s):

Experimental Study ◽

Heat Flux ◽

Surface Modification ◽

Surface Treatment ◽

Nuclear Power ◽

Power Plants ◽

Pool Boiling ◽

Heating Surface ◽

Thermal Systems ◽

Multi Scale

The need to operate thermal systems, including those in nuclear power plants, below the critical heat flux (CHF) requires inconvenient compromises between economy and safety. This has led to much research aimed at enhancing the CHF. CHF enhancement was recently noticed in nanofluids where the heating surface was fouled by nanoparticles. We attempted to imitate the micro/nano multi-scale structure of nanoparticle fouling by surface modification. In this study, surface treatment was used to change the surface wettability of a Zircaloy-4 heater. A pool boiling apparatus was developed based on the results of the surface treatment, and an experimental study was performed to investigate the increase in CHF.

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Effects of Fluid Properties and Surface Parameters on Pool Boiling of Porous and Pin-Fin Surfaces

ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer, Parts A and B ◽

10.1115/mnht2008-52187 ◽

2008 ◽

Cited By ~ 2

Author(s):

Liang-Han Chien ◽

Shu-Che Lee ◽

Hon-Zen Wang ◽

Shao-Wen Chen

Keyword(s):

High Speed ◽

Smooth Surface ◽

Pool Boiling ◽

Particle Diameter ◽

Saturation Temperature ◽

Porous Surface ◽

Average Particle ◽

Transfer Coefficients ◽

Pin Fin ◽

Fluid Properties

The present experimental study investigated the effect of heater size on pool boiling performance for various fluids. Water, methanol and FC-72 were tested at 50 and 70°C saturation temperature on a smooth surface, a porous surface, a pin-fin surface and a structured surface. The boiling test vessel has a 31 mm by 31 mm internal base area and 100 mm height. The sizes of the heating area are: 31×31, 12×12, 9×9, or 6×6 mm2. The test results of all the three fluids showed that boiling performance is independent on heater size for 31mm × 31mm, 12mm × 12 mm heaters, but the boiling heat transfer coefficients for the smooth surface having 6 mm × 6 mm heating area is approximately 70∼100% higher than those for the 12 mm × 12 mm heating area. The 0.2 mm thick square pin-fins, having 0.2 mm depth and 0.4 mm pitch, yields 2-to-3 folds enhancement of boiling performance in FC-72. For methanol and FC-72, the porous surface yields up to seven folds boiling enhancement as compared with the smooth surface. However, the enhancement ratio of the porous surface, having 0.15 mm average particle diameter, is only 2.3 for water. Boiling phenomena observation by a high speed video system showed that the bubble size depends on surface geometries and fluid properties.

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Multi-Scale Thermal Analysis for Design of SiC-Based Medium Voltage Motor Drive

ASME 2019 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2019-6631 ◽

2019 ◽

Author(s):

J. Emily Cousineau ◽

Kevin Bennion ◽

Karun Potty ◽

He Li ◽

Risha Na ◽

...

Keyword(s):

Thermal Analysis ◽

System Level ◽

Motor Drive ◽

Cfd Simulations ◽

Medium Voltage ◽

Pin Fin ◽

Multi Scale ◽

Fea Model ◽

Fast Running ◽

Time Required

Abstract This paper describes a multi-scale thermal analysis approach for the design of an air-cooled 1.7-kV SiC MOSFET-based medium-voltage variable-speed motor drive. The scope of the models and required efficient and flexible thermal models to be developed. Two modeling techniques are described that significantly reduced model run time and enabled more complex models to be run faster while retaining needed accuracy. The first technique uses the effectiveness-NTU method to extract convection boundary conditions from a CFD model that can be applied to a fast-running FEA model. The second is a porous media technique that enables system-level CFD simulations that incorporate effects from heat exchangers (e.g., pin fin heat sinks) that run in a fraction of the time required for fully resolved CFD simulations. The multi-scale approach to the thermal analysis enabled fast and accurate simulation for the converter design ranging from the die level up to the full system with 36 submodules. The modeling results were validated against experimental data from system tests performed by OSU.

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