Cooling performance of micromachined self-oscillating reed actuators in heat transfer channels with integrated diagnostics

This paper presents heat transfer (HT) performance of small-scale MEMS-enhanced self-powered oscillating actuators for applications in highly-compact high-power air-cooled heat exchangers. Commercial air-cooled heat sinks are typically much larger than the systems they must cool due to large air-side thermal resistance. Our work is applying MEMS technologies to reduce this thermal resistance via the integration of small-scale oscillating actuators into small heat exchangers. Improved HT performance either yields smaller heat sinks or higher heat fluxes. These mm-scale actuators were built using MEMS manufacturing technologies such as laser micromachining, lamination, and/or metal patterning and etching. Conceptually, oscillating reeds inserted into the channels of an air-cooled heat sink induce small-scale motions in low-Reynolds number flows, which increases HT efficacy. Using MEMS-enhanced reed actuators, we experimentally demonstrated local HT enhancement up to 250% in microfabricated channels monitored by integrated temperature sensors.