Experimental Study of Flow Critical Heat Flux in Low Concentration Water-Based Nanofluids

2008 ◽  
Author(s):  
Sung Joong Kim ◽  
Tom McKrell ◽  
Jacopo Buongiorno ◽  
Lin-Wen Hu
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Test Section ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Outlet Temperature ◽  
Flow Loop ◽  
Maximum Heat ◽  
Low Concentration

Nanofluids are known as dispersions of nano-scale particles in solvents. Recent reviews of pool boiling experiments using nanofluids have shown that they have greatly enhanced critical heat flux (CHF). In many practical heat transfer applications, however, it is flow boiling that is of particular importance. Therefore, an experimental study was performed to verify whether or not a nanofluid can indeed enhance the CHF in the flow boiling condition. The nanofluid used in this work was a dispersion of aluminum oxide particles in water at very low concentration (≤0.1 v%). CHF was measured in a flow loop with a stainless steel grade 316 tubular test section of 5.54 mm inner diameter and 100 mm long. The test section was designed to provide a maximum heat flux of about 9.0 MW/m2, delivered by two direct current power supplies connected in parallel. More than 40 tests were conducted at three different mass fluxes of 1,500, 2,000, and 2,500 kg/m2sec while the fluid outlet temperature was limited not to exceed the saturation temperature at 0.1 MPa. The experimental results show that the CHF could be enhanced by as much as 45%. Additionally, surface inspection using Scanning Electron Microscopy reveals that the surface morphology of the test heater has been altered during the nanofluid boiling, which, in turn, provides valuable clues for explaining the CHF enhancement.

Experimental Study of Flow Critical Heat Flux in Alumina-Water, Zinc-Oxide-Water, and Diamond-Water Nanofluids

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Sung Joong Kim ◽  
Tom McKrell ◽  
Jacopo Buongiorno ◽  
Lin-Wen Hu
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Zinc Oxide ◽  
Critical Heat Flux ◽  
Mass Flux ◽  
Flow Boiling ◽  
Thermal Conditions ◽  
Nanometer Range ◽  
Low Concentration ◽  
Mass Fluxes

It is shown that addition of alumina, zinc-oxide, and diamond particles can enhance the critical heat flux (CHF) limit of water in flow boiling. The particles used here were in the nanometer range (<100 nm) and at low concentration (≤0.1 vol %). The CHF tests were conducted at 0.1 MPa and at three different mass fluxes (1500 kg/m2 s, 2000 kg/m2 s, and 2500 kg/m2 s). The thermal conditions at CHF were subcooled. The maximum CHF enhancement was 53%, 53%, and 38% for alumina, zinc oxide, and diamond, respectively, always obtained at the highest mass flux. A postmortem analysis of the boiling surface reveals that its morphology is altered by deposition of the particles during boiling. Additionally, the wettability of the surface is substantially increased, which seems to correlate well with the observed CHF enhancement.

Experimental study of critical heat flux enhancement during forced convective flow boiling of nanofluid on a short heated surface

2010 ◽  
Vol 36 (5) ◽  
pp. 375-384 ◽  
Author(s):  
Ho Seon Ahn ◽  
Hyungdae Kim ◽  
HangJin Jo ◽  
SoonHo Kang ◽  
WonPyo Chang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Convective Flow ◽  
Flow Boiling ◽  
Heated Surface ◽  
Flux Enhancement ◽  
Forced Convective Flow

Ultra High Critical Heat Flux During Forced Flow Boiling Heat Transfer With an Impinging Jet

2003 ◽  
Vol 125 (6) ◽  
pp. 1038-1045 ◽  
Author(s):  
Yuichi Mitsutake ◽  
Masanori Monde
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Flow Boiling ◽  
Heated Surface ◽  
Forced Flow ◽  
Maximum Heat ◽  
Subcooled Liquid ◽  
System Pressure ◽  
Maximum Heat Flux ◽  
Flow Boiling Heat Transfer

An ultra high critical heat flux (CHF) was attempted using a highly subcooled liquid jet impinging on a small rectangular heated surface of length 5∼10mm and width 4 mm. Experiments were carried out at jet velocities of 5∼60m/s, a jet temperature of 20°C and system pressures of 0.1∼1.3MPa. The degree of subcooling was varied from 80 to 170 K with increasing system pressure. The general correlation for CHF is shown to be applicable for such a small heated surface under a certain range of conditions. The maximum CHF achieved in these experiments was 211.9 MW/m2, recorded at system pressure of 0.7 MPa, jet velocity of 35 m/s and jet subcooling of 151 K, and corresponds to 48% of the theoretical maximum heat flux proposed by Gambill and Lienhard.

scholarly journals An experimental study of critical heat flux of flow boiling in minichannels at high reduced pressure

2017 ◽  
Vol 891 ◽  
pp. 012025
Author(s):  
A V Belyaev ◽  
A V Dedov ◽  
A N Varava ◽  
A T Komov
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Flow Boiling ◽  
Reduced Pressure

scholarly journals Experimental study of critical heat flux at flow boiling of R125 in small diameter channel

2019 ◽  
Vol 1370 ◽  
pp. 012005
Author(s):  
A I Zanosko ◽  
A V Dedov ◽  
A V Belyaev
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Flow Boiling ◽  
Small Diameter ◽  
Diameter Channel

Experimental study of critical heat flux in flow boiling under subatmospheric pressure in a vertical square channel

2019 ◽  
Vol 130 ◽  
pp. 514-522 ◽  
Author(s):  
Nathan Colgan ◽  
Joseph L. Bottini ◽  
Raúl Martínez-Cuenca ◽  
Caleb S. Brooks
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Flow Boiling ◽  
Subatmospheric Pressure ◽  
Square Channel

Study on Saturated Flow Boiling Heat Transfer Under Vibration Conditions

2012 ◽  
Author(s):  
Yoshitaro Fujiyama ◽  
Hiroyasu Ohtake
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Test Section ◽  
Low Voltage ◽  
Flow Boiling ◽  
Heating Surface ◽  
Nucleate Boiling ◽  
Circuit Board ◽  
Vertical Position ◽  
Saturated Flow

The ability to predict void formation, void fraction and critical heat flux —CHF— in flow boiling under oscillatory flow and vibration conditions is important to the safety technology of nuclear reactor during earthquake. In the present study, the onset of nucleate boiling —ONB— and CHF on saturated flow boiling under vibration conditions were investigated experimentally. Steady state experiments were conducted using a copper thin-film and saturated and subcooled water at 0.1 MPa. The liquid velocity was 0.25, 1.38, 3.20 and 4.07 m/s, respectively; the liquid subcooling was 0 K and 20 K. A heater was made of a printed circuit board. A test section was a rectangular flow channel of 10 mm width and 10 mm height. The test heater was heated by Joule heating of d.c. current from a low-voltage high-current stabilizer. The heating rate of the heater was determined from supplied current and voltage. The temperature of the heater was obtained by referring to the measured electric resistance. The test section was arranged for horizontal position facing upward and for vertical position, respectively. For the vibration condition, the test section was set on a vibration table. The ONB was decided as an occurrence of the first boiling bubble. The critical heat flux was determined as that immediately before the heating surface physically burned-out. The CHF on saturated flow boiling under vibration conditions were investigated experimentally.

Flow Boiling of R134a in Circular Microtubes—Part II: Study of Critical Heat Flux Condition

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Saptarshi Basu ◽  
Sidy Ndao ◽  
Gregory J. Michna ◽  
Yoav Peles ◽  
Michael K. Jensen
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Heat Flux ◽  
Flow Pattern ◽  
Flow Regime ◽  
Critical Heat Flux ◽  
Flow Boiling ◽  
Saturation Pressure ◽  
Absolute Error ◽  
Two Phase

A detailed experimental study was carried out on the critical heat flux (CHF) condition for flow boiling of R134a in single circular microtubes. The test sections had inner diameters (ID) of 0.50 mm, 0.96 mm, and 1.60 mm. Experiments were conducted over a large range of mass flux, inlet subcooling, saturation pressure, and vapor quality. CHF occurred under saturated conditions at high qualities and increased with increasing mass fluxes, tube diameters, and inlet subcoolings. CHF generally, but not always, decreases with increasing saturation pressures and vapor qualities. The experimental data were mapped to the flow pattern maps developed by Hasan [2005, “Two-Phase Flow Regime Transitions in Microchannels: A Comparative Experimental Study,” Nanoscale Microscale Thermophys. Eng., 9, pp. 165–182] and Revellin and Thome [2007, “A New Type of Diabatic Flow Pattern Map for Boiling Heat Transfer in Microchannels,” J. Micromech. Microeng., 17, pp. 788–796]. Based on these maps, CHF mainly occurred in the annular flow regime in the larger tubes. The flow pattern for the 0.50 mm ID tube was not conclusively identified. Four correlations—the Bowring correlation, the Katto-Ohno correlation, the Thome correlation, and the Zhang correlation—were used to predict the experimental data. The correlations predicted the correct experimental trend, but the mean absolute error (MAE) was high (>15%) A new correlation was developed to fit the experimental data with a MAE of 10%.

Experimental study on critical heat flux during flow boiling of R134a in a vertical helically coiled tube

2020 ◽  
Vol 234 (15) ◽  
pp. 3094-3101
Author(s):  
Xiaojuan Niu ◽  
Huaijie Yuan ◽  
Liang Zhao
Keyword(s):  
Experimental Study ◽  
Heat Flux ◽  
Critical Heat Flux ◽  
Wall Temperature ◽  
Mass Flux ◽  
Flow Boiling ◽  
Vapor Quality ◽  
Coiled Tube ◽  
Helically Coiled Tube ◽  
System Pressure

This paper carried out an experimental study on the critical heat flux during flow boiling of R134a in a vertical helically coiled tube. The length, inner diameter, coil diameter, and pitch of the test tube were 1.85 m, 8 mm, 205 mm, and 25 mm, respectively. Experiments cover the mass flux range of 190–400 kg·m−2·s−1, heat flux of 15–55 kW·m−2, inlet pressure of 0.8–1.1 MPa, and inlet vapor quality of 0.01–0.35. The effects of critical heat flux identification method, mass flux, system pressure, and inlet vapor quality on critical heat flux were presented. The critical heat flux obtained by the wall temperature rise method was larger than that obtained by the wall temperature oscillation method. The deviation of the critical heat flux corresponding to two methods, including wall temperature rises sharply above 10 ℃ and wall temperature drastic oscillation, was about 20% under the present experimental conditions. The critical heat flux increased with mass flux while it decreased with the inlet vapor quality and pressure. The experiment data were compared with four existing empirical correlations. A new correlation is proposed for critical heat flux prediction in vertical helical tubes.

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