scholarly journals Closure to “Discussions of ‘Investigations of Heat-Transfer Coefficients for Air Flow Through Round Jets Impinging Normal to a Heat-Transfer Surface’” (1963, ASME J. Heat Transfer, 85, pp. 243–244)

1963 ◽  
Vol 85 (3) ◽  
pp. 244-245
Author(s):  
G. C. Huang
Keyword(s):  
Heat Transfer ◽  
Air Flow ◽  
Heat Transfer Surface ◽  
Transfer Coefficients ◽  
Round Jets ◽  
Heat Transfer Coefficients ◽  
Flow Through

Investigations of Heat-Transfer Coefficients for Air Flow Through Round Jets Impinging Normal to a Heat-Transfer Surface

1963 ◽  
Vol 85 (3) ◽  
pp. 237-243 ◽  
Author(s):  
G. C. Huang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Surface ◽  
Practical Application ◽  
Transfer Coefficients ◽  
Average Heat ◽  
Round Jets ◽  
Heat Transfer Coefficients ◽  
High Magnitude ◽  
Single Jet ◽  
Flow Through

In this paper, empirical equations of local as well as average heat-transfer coefficients of single jet system were derived. Two aspects of multiple jet systems have been studied. One concerns mainly the uniform distribution of heat-transfer coefficients and economy of power consumption. The other concerns the high magnitude of heat-transfer coefficients and the interference among jets. The experiments were conducted at Reynolds number from 103 to 104 and hole size from 1/8 to 1/4 in. diameter. An attempt was made to correlate empirical data to render practical application possible.

An Analytical Study of the Optimized Performance of an Impingement Heat Sink

2004 ◽  
Vol 126 (4) ◽  
pp. 528-534 ◽  
Author(s):  
S. B. Sathe ◽  
B. G. Sammakia
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
High Performance ◽  
Cross Flow ◽  
High Heat ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
High Heat Transfer ◽  
Flow Through

The results of a study of a new and unique high-performance air-cooled impingement heat sink are presented. An extensive numerical investigation of the heat sink performance is conducted and is verified by experimental data. The study is relevant to cooling of high-power chips and modules in air-cooled environments and applies to workstations or mainframes. In the study, a rectangular jet impinges on a set of parallel fins and then turns into cross flow. The effects of the fin thickness, gap nozzle width and fin shape on the heat transfer and pressure drop are investigated. It is found that pressure drop is reduced by cutting the fins in the central impingement zone without sacrificing the heat transfer due to a reduction in the extent of the stagnant zone. A combination of fin thicknesses of the order of 0.5 mm and channel gaps of 0.8 mm with appropriate central cutout yielded heat transfer coefficients over 1500 W/m2 K at a pressure drop of less than 100 N/m2, as is typically available in high-end workstations. A detailed study of flow-through heat sinks subject to the same constraints as the impingement heat sink showed that the flow-through heat sink could not achieve the high heat transfer coefficients at a low pressure drop.

Periodic Streamwise Variations of Heat Transfer Coefficients for Inline and Staggered Arrays of Circular Jets with Crossflow of Spent Air

1980 ◽  
Vol 102 (1) ◽  
pp. 132-137 ◽  
Author(s):  
L. W. Florschuetz ◽  
R. A. Berry ◽  
D. E. Metzger
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Transfer Surface ◽  
Test Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Circular Jets ◽  
Impinging Flow

Heat transfer characteristics were measured for inline and staggered arrays of circular jets impinging on a surface parallel to the jet orifice plate. The impinging flow was constrained to exit in a single direction along the channel formed by the jet plate and the heat transfer surface. In this configuration the air discharged from upstream transverse rows of jet holes imposes a crossflow of increasing magnitude on the succeeding downstream jet rows. Streamwise heat transfer coefficient profiles were determined for a streamwise resolution of one-third the streamwise hole spacing, utilizing a specially constructed test surface. These profiles are characterized by significant periodic variations. The downstream amplitudes are diminished by the increasing crossflow magnitude, but can persist for at least ten rows of holes. Results were obtained for streamwise hole spacings of 5, 10, and 15 hole diameters; transverse hole spacings of 4, 6, and 8 diameters; and channel heights of 1, 2, and 3 diameters. The number of transverse hole rows was fixed at ten for all configurations. The characteristics of the periodic variations are presented and discussed as a function of the geometric parameters, including the effect of hole pattern.

HEAT TRANSFER IN A FLUIDIZED SOLIDS BED

1950 ◽  
Vol 28f (8) ◽  
pp. 287-307 ◽  
Author(s):  
J. Klassen ◽  
P. E. Gishler ◽  
A. Baerg
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Bulk Density ◽  
Particle Shape ◽  
Air Flow ◽  
Transfer Coefficients ◽  
Air Velocity ◽  
Heat Transfer Coefficients ◽  
Minimum Fluidizing Velocity

Heat transfer coefficients have been determined in a fluidized solids bed under a wide variety of conditions. The variables studied were particle size, bulk density under nonfluidized conditions, particle shape, and air velocity. Simple correlations have been established predicting the value of h in the air flow range investigated. An equation predicting the minimum fluidizing velocity has also been derived.

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