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Heat Transfer Characteristics for a Confined Stationary MCM Disk with Round Jet Array Impingement
C.Y. Lee, C.J. Fang, C.H. Peng and Y.H. Hung

An effective method for exploring the thermal characteristics for a stationary multichip module disk with confined air jet-array Impingement has been successfully developed by using design of experiments combined with Central Composite Design. The relevant parameters influencing heat transfer performance include the steadystate Grashof number (Grs), ratio of jet separation distance to nozzle diameter (H/d) and jet Reynolds number (Rej). Their effects on heat transfer characteristics have been systematically explored. An axisymmetrical temperature distribution is ensured for various Grs, Rej, Rer and H/d ratios. The temperature distributions on the stationary MCM disk surface with jet array impingement are more uniform than the confined single round jet impingement cases. The effects of Grs, H/d and Rej on the normalized transient chip convective heat flux are not significant. A new generalized correlation is proposed to represent transient convective heat fluxes for the cases of a stationary MCM disk with confined round jet array impingement. Besides, an empirical correlation of stagnation Nusselt number for jet array impingement at r/R = 0 in terms of Rej and H/d are presented. Comparisons between the predictions and the present experimental jet array data are made with a satisfactory agreement. As compared with the present experimental steady-state data of single round jet impingement, the maximum average heat transfer enhancement at stagnation point of jet array impingement is 607%. For local and average heat transfer behavior, the highest chip heat transfer occurs at the MCM disk center, i.e. r/R = 0 and decreases slightly along the distance from the surface center toward the surface edge. An empirical correlation of steady-state average Nusselt number in terms of Rej and H/d are presented. As compared with the steady-state experimental data of a stationary MCM disk with confined single round jet impingement, the average heat transfer enhancements for steady-state average Nusselt number is 602%.

Keywords: Round Jet Array Impingement, MCM Disk, Design of Experiments, Ratio of Jet Separation Distance to Nozzle Diameter, Central Composite Design, Single Round Jet impingement.

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