Jet Impingement Cooling Of Microelectronic Systems

Electronic systems have now grown smaller resulting in very high heat generation compared to previous systems. Jet
impingement cooling has been identified to be useful in the electronics cooling due to its high heat removal capabilities.
Jet impingement cooling in electronic packages is carried out numerically using a commercial finite volume code,
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 (d) of 3.18 mm at several
nozzle to target plate spacing (H/d) ranging from 1 to 8. The turbulent jet Reynolds numbers considered are 8500,
10000 and 13000 with a perflourinated dielecric fluid Flourinert-77 (FC77) as the working fluid. The flow field and
heat transfer are solved using the standard high Reynolds number k-e turbulence model. A more detailed grid refinement
compared to previous investigations is utilized. The present predictions with the standard high Reynolds number k-e
turbulence model with modified grid refinement are able to produce results with maximum errors of 4.6% and 9.9% for
stagnation and averaged heat transfer coefficients respectively. In earlier prediction, the deviations from the experimental
results are observed to be a maximum of 60.4% for the stagnation heat transfer coefficient and a maximum of 56.6% for
the averaged heat transfer coefficient. Numerical predictions are also carried out for those cases of H/d and Re for which
neither experimental data nor numerical predicted data are available in the literature. From the predicted results, correlations
are developed to determine the stagnation heat transfer coefficient, the average heat transfer.