Publication: Application of jet impingement in the cooling of electronic products
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Date
2002-03-01
Authors
Sanjiv, Nair Sagaram
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Abstract
Jet impingement cooling has long been used in the industries for controlling
temperature in material processing, cooling equipments, cryosurgery and electronics
cooling. It has been identified to be useful to electronics cooling due to its high heat
removal capabilities. Electronic systems have now grown smaller resulting in very high
heat generation compared to previous systems, requiring cooling solutions such as jet
impingement.
Jet impingement cooling in electronic packages is carried out numerically using
FLUENTTM. The local heat transfer coefficients on a heat source due to a normally
impinging, axisymmetric, confined and submerged liquid jet are investigated. Numerical
predictions are made for nozzle diameter of 3.18 mm at several nozzles to target plate
spacing (H/d) ranging from 2 to 4. The Reynolds numbers considered are 8500, 10000 and
13000 with a perfluorinated dielectric fluid Fluorinert-77 (FC-77) as the working fluid. The
flow field and heat transfer are solved using the standard high Reynolds number k-
turbulence model. A more detailed mesh refinement compared to previous investigations is
utilized.
The results of the analysis show the flow field predictions and the temperature
contours to be similar to the results obtained experimentally by researchers. It was found
that when the nozzle to target plate spacing (H/d) increases, the primary toroidal
recirculation zone moves further away from the jet axis and closer to the target plate. The
temperature gradient near the stagnation zone is also found to be less compared to that near
the end of the heat source. The local and average heat transfer coefficients are also
calculated and are presented together with the analysis where it was noted that as Reynolds
numbers and H/d increases, the heat transfer coefficients increases.