Heat Transfer From an Oscillating Horizontal Wire to Water and Ethylene Glycol

1966 ◽  
Vol 88 (4) ◽  
pp. 359-363 ◽  
Author(s):  
W. R. Penney ◽  
T. B. Jefferson
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Ethylene Glycol ◽  
Mixed Convection ◽  
Large Amplitude ◽  
Previous Investigation ◽  
Low Frequency ◽  
Fluid Properties ◽  
Correlate Data ◽  
Horizontal Wire

An experimental investigation has been conducted to investigate the effect of low-frequency, large-amplitude, horizontal oscillations on convection from a heated horizontal wire (0.008 in. dia) to water and ethylene glycol. Frequencies to 4.5 cps and amplitudes to 2.5 in. were employed. Comparison with a previous investigation has shown that, in the range of this investigation, heat transfer for vertical oscillations is greater than for horizontal oscillations. Comparison of data for water and ethylene glycol showed that previous methods of presenting mixed convection (free plus forced convection) data would not suffice for widely varying fluid properties. A correlating method was developed which successfully correlated the data of this investigation but failed to correlate data of previous investigations. Deficiencies of this method are discussed, and recommendations are given for future correlating methods.

Heat Transfer From an Oscillating Horizontal Wire to Water

1962 ◽  
Vol 84 (3) ◽  
pp. 251-254 ◽  
Author(s):  
F. K. Deaver ◽  
W. R. Penney ◽  
T. B. Jefferson
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Reynolds Number ◽  
Mixed Convection ◽  
Low Frequency ◽  
Mean Velocity ◽  
Transfer Rates ◽  
Low Frequency Oscillations ◽  
The Mean ◽  
Horizontal Wire

An investigation has been made to determine the effect of low frequency oscillations of relatively large amplitude on the rate of heat transfer from a small horizontal wire to water. Frequencies from 0 to 4.25 cps and amplitudes to 2.76 in. were employed. Temperature differences up to 140 deg F provided heat flux from 2000 to 300,000 Btu/hr ft2. A Reynolds number was defined based on the mean velocity of the wire, and it was shown that heat-transfer rates may be predicted by either forced, free, or mixed convection correlations depending on the relative magnitudes of Reynolds and Grashof numbers.

Effects of Various Physical and Numerical Parameters on Heat Transfer in Vertical Passages at Relatively Low Heat Loading

2011 ◽  
Vol 133 (9) ◽  
Author(s):  
Amir Keshmiri
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Reynolds Numbers ◽  
Boussinesq Approximation ◽  
Low Flow ◽  
Physical Parameters ◽  
Pipe Length ◽  
Viscosity Models ◽  
Heat Loading ◽  
Fluid Properties

The present work is concerned with the modeling of buoyancy-modified mixed convection flows, such flows being representative of low-flow-rate flows in the cores of Gas-cooled Reactors. Three different eddy viscosity models (EVMs) are examined using the in-house code, “CONVERT.” All fluid properties are assumed to be constant, and buoyancy is accounted for within the Boussinesq approximation. Comparison is made against experimental measurements and the direct numerical simulations (DNS). The effects of three physical parameters including the heat loading, Reynolds number, and pipe length on heat transfer have been examined. It is found that by increasing the heat loading, three thermal-hydraulic regimes of “early onset of mixed convection,” “laminarization,” and “recovery” were present. At different Reynolds numbers, the three thermal-hydraulic regimes are also evident. The k-ε model of Launder and Sharma was found to be in the closest agreement with consistently normalized DNS results for the ratio of mixed-to-forced convection Nusselt number (Nu/Nu0). It was also shown that for the “laminarization” case, the pipe length should be at least “500× diameter” in order to reach a fully developed solution. In addition, the effects of two numerical parameters namely buoyancy production and Yap length-scale correction terms have also been investigated and their effects were found to be negligible on heat transfer and friction coefficient in ascending flows.

Heat Transfer Performance of Titanium Oxide in Ethylene Glycol Based Nanofluids under Transition Flow

2014 ◽  
Vol 660 ◽  
pp. 684-688 ◽  
Author(s):  
Khamisah Abdul Hamid ◽  
Wan Hamzah Azmi ◽  
Rizalman Mamat ◽  
Nur Ashikin Usri
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Ethylene Glycol ◽  
Titanium Oxide ◽  
Transition Region ◽  
Constant Heat Flux ◽  
Transition Flow ◽  
Enhancement Of Heat Transfer ◽  
Number Range

The needs to improve the efficiency of coolants undeniably become one of the concerns in cooling systems technologies nowadays. Nanofluid as coolant is invented and studied where it can provide better option for users due to augmentation in properties. This study provides experimental investigation on Titanium Oxide dispersed in water and ethylene glycol mixture under transition region with Reynolds number range of 2000 < Re <10000. Three volume concentrations are used which are 0.5 %, 1.0 % and 1.5 % for heat transfer experimental investigation under working temperature of 30 °C at constant heat flux of 600 W. The Nusselt number of the nanofluid increase with the increasing of Reynolds number at 1.5 % concentration, slightly higher than based fluid. The finding on the heat transfer coefficient shows enhancement of 2.1 % achieved by Titanium Oxide nanofluid at 1.5 % volume concentration. For 0.5 % and 1.0 % concentration, no enhancement of heat transfer achieved for the fluid flow under transition region at temperature of 30 °C.

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