Experimental investigation of transient critical heat flux of water-based zinc–oxide nanofluids

This study presents a detailed experimental investigation of the combined effects of pressure and subcooling on nucleate pool boiling and critical heat flux (CHF) for degassed fluorocarbon FC-72 boiling on a plastic pin-grid-array (PPGA) chip package. In these experiments pressure was varied between 101.3 and 303.9 kPa and the subcooling ranged from 0 to 65°C. As expected, lower wall superheats resulted from increases in pressure, while subcooling had a minimal effect on fully developed pool boiling. However, the superheat reductions and CHF enhancements were found to be smaller than those predicted by existing models. The CHF for saturated liquid conditions increased by nearly 17 percent for an increase in pressure from 101.3 to 202.7 kPa. In experiments with both FC-72 and FC-87 further increases in pressure did not produce any significant increase in CHF. At a pressure of 101.3 kPa a subcooling of 30°C increased CHF on horizontal upward-facing chips by approximately 50 percent, as compared to 70 percent on vertically oriented packages. The enhancement in CHF due to subcooling decreased rapidly with increasing pressure, and the data showed that the influence of pressure and subcooling on CHF is not additive. A correlation to predict pool boiling CHF under the combined effects of pressure and subcooling is proposed.

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Derivation of mechanistic critical heat flux model for water based on flow instabilities

International Communications in Heat and Mass Transfer ◽

10.1016/s0735-1933(96)00092-9 ◽

1996 ◽

Vol 23 (8) ◽

pp. 1109-1119 ◽

Cited By ~ 6

Author(s):

Soon Heung Chang ◽

Yun Il Kim ◽

Won-Pil Baek

Keyword(s):

Heat Flux ◽

Critical Heat Flux ◽

Flow Instabilities ◽

Water Based ◽

Flux Model ◽

Heat Flux Model

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Critical Heat Flux Enhancement in Water-Based Nanofluid With Honeycomb Porous Plate on Large Heated Surface

Volume 5: Student Paper Competition ◽

10.1115/icone24-60560 ◽

2016 ◽

Cited By ~ 1

Author(s):

Suazlan Mt Aznam ◽

Shoji Mori ◽

Kunito Okuyama

Keyword(s):

Heat Flux ◽

Critical Heat Flux ◽

Heated Surface ◽

Porous Plate ◽

High Heat ◽

High Heat Flux ◽

Heater Surface ◽

Solid Structure ◽

Water Based ◽

Plain Surface

Heat removal through pool boiling is limited by the phenomena of critical heat flux (CHF). CHF enhancement is vitally important in order to satisfy demand for the cooling technology with high heat flux in In Vessel Retention (IVR). Various surface modifications of the boiling surface, e.g., integrated surface structures and coating of a micro-porous have been proven to effectively enhance the CHF in saturated pool boiling. We have been proposed a novel method of attaching a honeycomb structured porous plate on a considerably large heater surface. Previous results, by the authors in [1] reported that CHF has been enhanced experimentally up to more than approximately twice that of a plain surface (approximately 2.0 to 2.5 MW/m2) with a diameter of 30 mm heated surface. However, it is necessary to demonstrate the method together with infinite heater surface within laboratory scale. It is important that cooling techniques for IVR could be applicable to a large heated surface as well as remove high heat flux. Objective of this study is to investigate the CHF of honeycomb porous plate and metal solid structure in nanofluid boiling or water boiling on a large heated surface. Water-based nanofluid offers good wettability and capillarity. While metal solid structure is installed on honeycomb porous plate to increase the number of vapor jet. Experimental results of honeycomb porous plate and combination of honeycomb porous plate and metal solid structure in water-based nanofluid boiling shows that CHF is increased up to twice [2] and thrice, respectively compared to plain surface in water boiling. To the best of the author’s knowledge, the highest value (3.1 MW/m2) was obtained for a large heated surface having a diameter of 50 mm which is regarded as infinite heated surface. This demonstrates potential for general applicability to have more safety margin in IVR method.

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Experimental Investigation of Critical Heat Flux in Microchannels for Flow-Field Probes

ASME 2009 7th International Conference on Nanochannels, Microchannels and Minichannels ◽

10.1115/icnmm2009-82214 ◽

2009 ◽

Cited By ~ 10

Author(s):

Ali Kos¸ar ◽

Yoav Peles ◽

Arthur E. Bergles ◽

Gregory S. Cole

Keyword(s):

Heat Flux ◽

Experimental Investigation ◽

Critical Heat Flux ◽

Mass Velocity ◽

Thermal Condition ◽

Average Error ◽

New Correlation ◽

Hydraulic Conditions ◽

Data Points ◽

Heated Length

Critical heat flux (CHF) of water in circular stainless steel microchannels with inner diameters ranging from ∼127μm to ∼254 μm was investigated. Forty-five CHF data points were acquired over mass velocities ranging from 1,200 kg/m2s to 53,000 kg/m2s, heated lengths from 2 cm to 8 cm, and exit qualities from −0.2 to 0.15. Most of the exit qualities fell below 0.1. It was found that CHF conditions were more dependent on mass velocity and heated length than on exit thermal condition. The results were also compared to six CHF correlations, with a mean average error ranging from 22% to 261.8%. A new correlation was proposed to better predict the critical heat flux data under the thermal-hydraulic conditions studied in this investigation. In developing the correlation, 319 data points were added from two previous studies.

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Effect of Channel Blockage on Critical Heat Flux for a Horizontal Cylinder in Crossflow

Journal of Heat Transfer ◽

10.1115/1.2836322 ◽

1995 ◽

Vol 117 (4) ◽

pp. 998-1002 ◽

Cited By ~ 1

Author(s):

R. Dowlati ◽

M. Kawaji ◽

I. D. Sardjono ◽

S. T. Revankar

Keyword(s):

Heat Flux ◽

Experimental Investigation ◽

Critical Heat Flux ◽

Horizontal Tube ◽

Horizontal Cylinder ◽

Fluid Velocities ◽

Wide Range ◽

Channel Blockage ◽

Flow Blockage

An experimental investigation has been conducted on critical heat flux (CHF) on a horizontal tube in crossflow boiling R-113 at near atmospheric pressures. Data were obtained over a range of fluid velocities (up to 0.52 m/s), heater diameters (8 to 12.7 mm), and flow blockage factors (D/H = 0.31 to 0.5). The effect of the flow blockage on CHF was examined in detail and compared with other data and existing correlations. No significant effect of flow blockage was observed for D/H up to 0.5. An analytical modification of the Katto-Haramura CHF correlation is proposed to take into account the effect of flow blockage over a wide range of D/H.

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