Experimental Investigation of Heat Transfer by Natural Convection with Perforated Pin Fin Array

A six row pin-fin array was constructed with a spanwise spacing of 2.5 diameters, streamwise spacing of 1.5 diameters and a height to diameter ratio of 1. The streamwise stagger of alternate rows was continuously varied from fully in-line to fully staggered. Tests were carried out at Reynolds numbers of 2.7 × 104 and 2.3 × 104, corresponding to maximum velocities, in the low subsonic range, of 21 m/s and 18 m/s respectively. These results showed that the array averaged heat transfer was greatest from a fully staggered array and had a minimum at a stagger slightly greater than fully in-line. However, with increasing stagger, the array-averaged friction factor grew at a greater rate than the heat transfer. The ensuing analysis of the total array performance, considering both the magnitude of heat transfer and the losses within the array, showed that the fully in-line array had the highest ratio of heat transfer enhancement to friction factor enhancement. Therefore, if pressure loss was a design criterion, the fully in-line array was preferable. However, if pressure loss was not a constraint, then the staggered array was preferable.

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Endwall Heat Transfer Measurements in a Staggered Pin Fin Array With an Adiabatic Pin

Volume 4: Turbo Expo 2007, Parts A and B ◽

10.1115/gt2007-27432 ◽

2007 ◽

Cited By ~ 21

Author(s):

Forrest E. Ames ◽

Chad A. Nordquist ◽

Lindsay A. Klennert

Keyword(s):

Heat Transfer ◽

Turbulent Transport ◽

Infrared Camera ◽

Leading Edge ◽

Reynolds Numbers ◽

Skin Friction Coefficient ◽

Vortex System ◽

Flow Acceleration ◽

Pin Fin ◽

Pin Fin Array

Full surface endwall heat transfer distributions have been acquired in a staggered pin fin array with the use of an infrared camera. Values are presented at Reynolds numbers of 3000, 10,000 and 30,000 based on pin diameter and average velocity through adjacent pins. Average endwall Nusselt numbers agree closely with archival values at each Reynolds number. Locally averaged heat transfer levels show a substantial increase from the inlet through the first few rows and finally a nearly streamwise periodic condition in the second half of the eight row geometry. Increasing levels of heat transfer in the inlet region can be attributed to the leading edge vortex system, flow acceleration around pins, and the generation of turbulence. Distributions of turbulence intensity and turbulent scale are shown to help document the turbulent transport conditions through the array. Detailed endwall Nusselt number distributions are presented and compared at the three Reynolds numbers for the first four and last four rows. These detailed heat transfer distributions highlight the influence of the horseshoe vortex system in the entrance region and the wake generated turbulence throughout the pin fin array. Local velocity and turbulence distributions are presented together with local Stanton number and skin friction coefficient data to examine the aggressive nature of the turbulent mixing.

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Design of Streamwise Stagger Within a Pin Fin Array to Minimize Pressure Loss

Volume 10: Heat Transfer, Fluid Flows, and Thermal Systems, Parts A, B, and C ◽

10.1115/imece2008-66683 ◽

2008 ◽

Author(s):

Stephen A. Andrews ◽

William D. E. Allan

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Friction Factor ◽

Pressure Loss ◽

Electronics Cooling ◽

Cooling Load ◽

Finite Range ◽

Pin Fin ◽

Pin Fin Array ◽

Do So

An experiment was conducted on the effects of streamwise stagger on heat transfer and pressure drop in a pin-fin array. The data were analyzed so as to highlight how stagger could be used to design a pin fin array for the lowest possible pressure loss. Design of arrays for low pressure loss is important in electronics cooling applications. They require large amounts of heat to be extracted from fixed areas, using a minimum of power to do so. This analysis found that the minimum friction factor occurred at a streamwise stagger of approximately 12% of the range between fully inline and fully staggered. By fixing the pin diameter, varying the stagger resulted in a 63% reduction in friction factor with only a 18% reduction in the Nusselt number, based on the array footprint. Additionally, it was found that for a fixed Nusselt number, the pin diameter could vary within a finite range, with decreasing diameters permitting arrays with more efficient degrees of stagger which continued to carry the required heating/cooling load.

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Experimental Investigation on thermal-hydraulic performance of microchannel heat sink with airfoil pin fin array and supercritical carbon dioxide

10.1615/tfec2020.hte.031880 ◽

2020 ◽

Author(s):

Mostafa Asadzadeh ◽

Yoav Peles

Keyword(s):

Carbon Dioxide ◽

Experimental Investigation ◽

Supercritical Carbon Dioxide ◽

Heat Sink ◽

Hydraulic Performance ◽

Microchannel Heat Sink ◽

Pin Fin ◽

Pin Fin Array ◽

Supercritical Carbon

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