A series of experimental investigations on the studies related to transient- and steady-state cooling performance from the horizontally heated heat sinks with a confined slot jet impingement have been conducted. The relevant parameters influencing the transient convective cooling performance include the steady-state Grashof number, ratio of jet separation distance to nozzle width, ratio of heat sink height to nozzle width, and jet Reynolds number. The transient heat transfer behaviors such as the temperature distribution, local and average Nusselt numbers on the heated heat sinks have been systematically explored. Two empirical correlations of steady-state local and average Nusselt numbers are presented. Furthermore, a complete composite correlation of steady-state average Nusselt number for mixed convection due to jet impingement and buoyancy is proposed. This empirical correlation obtained by data regression is in good agreement with the experimental data. The maximum and average regression errors are 7.46% and 2.87%, respectively.

Transient heat transfer behavior from a horizontally confined ceramic-based MCM disk with jet impingement has been systematically explored. The relevant parameters influencing heat transfer performance are the steady-state Grashof number, jet Reynolds number, and ratio of jet separation distance to nozzle diameter. In addition, an effective time, ton, representing a certain transient time when the mixed convection effect due to jet impingement and buoyancy becomes significant relative to heat conduction, is introduced. Both the transient chip and average Nusselt numbers on the MCM disk surface decrease with time in a very beginning period of 0⩽t<ton, whereas it gradually increases or keeps constant with time and finally approaches the steady-state value in the period of ton⩽t<ts. As compared with the steady-state results, if the transient chip and average heat transfer behaviors may be considered as a superposition of a series of quasi-steady states, the transient chip and average Nusselt numbers in all the present transient experiments can be properly predicted by the existing steady-state correlations when t⩾4min in the power-on transient period.

A novel semi-empirical model with an improved single blow method for exploring the heat transfer performance of porous aluminum-foam heat sinks in a channel has been successfully developed. The influencing parameters such as the steady-state air preheating temperature ratio, Reynolds number and medium porosity on local and average heat transfer behavior of porous aluminum-foam heat sinks in a channel are explored. The heat transfer enhancement of using a porous heat sink in a channel to a hollow channel is, (Nu¯b)ss∕(Nu¯b)ε=1, much greater than unity and generally decrease with increasing Re. Furthermore, two new correlations of (Nu¯b)ss and (Nu¯i)ss in terms of ϴ,Re,Da,γ and ε are proposed. As compared with the results evaluated by the transient liquid crystal method, the channel wall temperatures predicted by the present semi-empirical model have a more satisfactory agreement with the experimental data, especially for the cases with smaller porosities. The limitations with relevant error maps of using the transient liquid crystal method in porous aluminum foam channels are finally postulated.

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