In this experiment, agitation is used in a rectangular channel for convective heat transfer enhancement. The channel under study is representative of a flow channel in an electronics cooling finned heat sink module. It is open at one end and has a translationally oscillating plate within it that agitates the flow. Contrary to the heat sink cooling channel, the test channel has no net through-flow so that agitation, isolated from throughflow effects, is studied. The channel is divided into three regions. The entry region is close to the open end of the channel. This would be near the fin tips in the finned heat exchanger channel. The base region is close to the other end of the channel where the flow makes an abrupt U-bend around the agitator plate. This is near the fin base region of a finned channel of a heat sink heat exchanger. The central region is between the two. Each region has special flow and convective heat transfer features for study. Ensemble-averaged velocities and RMS fluctuations of velocity are measured over the cycle. Measured data lend insight into the mixing phenomena in each region over the oscillation cycle. Unsteady heat flux measurements were made in each region and over the cycle to help in understanding the mechanisms affecting heat transfer. The unsteady heat flux characteristics in the entry and base regions seem to be more influenced by the RMS fluctuations of velocity, indicating that heat transfer in these regions is governed by turbulence generated by agitation. The unsteady heat flux trends in the central region seem to be more influenced by acceleration/deceleration of the flow than by turbulence-like structures.

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