scholarly journals Closure to “Discussion of ‘Experiments on Turbulent Heat Transfer in an Asymmetrically Heated Rectangular Duct’” (1966, ASME J. Heat Transfer, 88, p. 174)

1966 ◽  
Vol 88 (2) ◽  
pp. 174-174
Author(s):  
E. M. Sparrow ◽  
J. R. Lloyd ◽  
C. W. Hixon
Keyword(s):  
Heat Transfer ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Rectangular Duct

Maldistributed Inlet Flow Effects on Turbulent Heat Transfer and Pressure Drop in a Flat Rectangular Duct

1983 ◽  
Vol 105 (3) ◽  
pp. 527-535 ◽  
Author(s):  
E. M. Sparrow ◽  
N. Cur
Keyword(s):  
Heat Transfer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Rectangular Duct ◽  
Transfer Coefficients ◽  
Inlet Flow ◽  
Heat Transfer Coefficients ◽  
Flow Maldistribution

The effects of flow maldistribution caused by partial blockage of the inlet of a flat rectangular duct were studied experimentally. Local heat transfer coefficients were measured on the principal walls of the duct for two blockages and for Reynolds numbers spanning the range between 6000 and 30,000. Measurements were also made of the pressure distribution along the duct, and the fluid flow pattern was visualized by the oil-lampblack technique. Large spanwise nonuniformities of the local heat transfer coefficient were induced by the maldistributed flow. These nonuniformities persisted to far downstream locations, especially in the presence of severe inlet flow maldistributions. Spanwise-average heat transfer coefficients, evaluated from the local data, were found to be enhanced in the downstream portion of the duct due to the flow maldistribution. However, at more upstream locations, where the entering flow reattached to the duct wall following its separation at the sharp-edged inlet, the average coefficients were reduced by the presence of the maldistribution.

Effect of Rib Height and Pitch on the Thermal Performance of a Passage Disturbed by Detached Solid Ribs

1996 ◽  
Author(s):  
Tong-Miin Liou ◽  
Woei-Jiunn Shuy ◽  
Yu-Houe Tsao
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Pressure Measurements ◽  
Rectangular Duct ◽  
Height Ratio ◽  
Heat Transfer Augmentation ◽  
Spatially Periodic ◽  
The Difference

Laser holographic interferometry and pressure measurements are presented for the effects of rib-to-duct height ratio (H/2B), rib pitch-to-height ratio (Pi/H), and Reynolds number (Re) on the spatially periodic-fully developed turbulent heat transfer and friction in a rectangular duct of width-to-height ratio of 4:1 with an array of ribs detached from one wall at a clearance to rib-height ratio of 0.38. The range of H/2B, Pi/H, and Re examined were 0.13 to 0.26, 7 to 13, and 5×103 to 5×104, respectively. The difference in the H/2B dependence of the thermal performance between the detached and attached solid-rib array is documented. H/2B=0.17 and Pi/H=10 are found to provide the best thermal performance for the range of parameters tested. Compact heat transfer and friction correlations are developed. Additionally, it is found that heat transfer augmentation with a detached solid-rib array is superior to with a detached perforated-rib array, and the mechanism responsible for the difference is revealed by the complementary flow visualization results.

Experiments on Turbulent Heat Transfer in an Asymmetrically Heated Rectangular Duct

1966 ◽  
Vol 88 (2) ◽  
pp. 170-174 ◽  
Author(s):  
E. M. Sparrow ◽  
J. R. Lloyd ◽  
C. W. Hixon
Keyword(s):  
Heat Transfer ◽  
Rectangular Cross Section ◽  
Heated Wall ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Rectangular Duct ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
First Case ◽  
Symmetric Heating

An experimental investigation of the effect of asymmetrical heating on fully developed turbulent heat transfer has been carried out. The test apparatus was a rectangular duct of aspect ratio 5:1. The duct was constructed so that the two long sides of the rectangular cross section could be heated at different preselected rates, while the two short sides were unheated. Two cases of asymmetrical heating were studied: (a) One of the two long sides was heated, while the second was unheated; (b) both of the long sides were heated, with the heating rate at one side being twice that of the other. For the first case, the heat transfer coefficients are lower than those for the symmetrically heated duct. For the second case, the coefficients for the more strongly heated wall are also below the values for symmetrical heating, while the coefficients for the lesser-heated wall are greater than the symmetric heating results. These findings are in qualitative agreement with analytical predictions for the parallel-plate channel. Furthermore, by applying an analytically motivated correlation procedure (reference [10]), it was shown that overall Nusselt number results for asymmetric heating could be brought into virtual coincidence with those for symmetric heating.

The Characteristics of Turbulent Heat Transfer in a Curved Rectangular Duct With Various Aspect Ratios

2010 ◽  
Author(s):  
Hang Seok Choi ◽  
Tae Seon Park
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Turbulent Flow ◽  
Secondary Flow ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Rectangular Duct ◽  
Flow And Heat Transfer ◽  
Aspect Ratios ◽  
Turbulent Characteristics

The turbulent flow fields of a parallel plate or channel with spatially periodic condition have been widely investigated by many researchers. However the rectangular or square curved duct flow has not been fundamentally scrutinized in spite of its engineering significance, especially for cooling device. Hence, in the present study large eddy simulation is applied to the turbulent flow and heat transfer in a rectangular duct with 180° curved angle varying its aspect ratio. The turbulent flow and the thermal fields are calculated and the representative vortical motions generated by the secondary flow are investigated. From the results, the secondary flow has a great effect on the heat and momentum transport in the flow. With changing the aspect ratio, the effect of the geometrical variation to the secondary flow and its influence on the turbulent characteristics of the flow and heat transfer are studied.

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