Summary:

Heat removal has become an important factor in the advancement of microelectronics due to drastically integrated density of chips in digital devices and increased current-voltage handling capability of power electronic devices. Micro-channel heat sinks remove heat 50 times more efficiently than conventional methods. However, one-layered micro-channel heat sinks induce high temperatures which can produce thermal stress on the chips and packages. To avoid such high temperatures, a large pressure drop is necessary which moves the coolant through the cooling channels more rapidly, thus requiring a larger, noisier pumping system. Scientists at The Ohio State University have developed a multi-layered micro-channel heat sink with a current flow arrangement for cooling that is a substantial improvement over conventional one-layered micro-channel heat sink designs. The thermal performance and the temperature distribution for these types of micro-channels were analyzed and a procedure for optimizing the geometrical design parameters was developed. While the power supply system of the multi-layered design is not significantly more complicated than the one-layered design, the stream-wise temperature rise on the base of surface was substantially reduced. At the same time, the pressure drop required for the multi-layered heat sink was substantially smaller than the one-layer design. It is shown that the thermal resistance is as low as 0.03 ?C/W for micro-channel heat sinks, which is substantially lower than conventional channel-sized heat sinks.

Potential Applications:

The multi-layered micro-channel design is ideal for the electronics semiconductor industry. More efficient cooling of solid-state radar systems, diode lasers, and mainframe and supercomputers are just a few of the applications. Using this technology for laser cooling is simpler than for microelectronics cooling. Research has demonstrated that the method works quite well for surfaces with a diameter of roughly up to 10 cm.

Advantages:

1. Cools far more efficiently than conventional cooling methods
2. Cools surfaces as well as single-layer micro-channels but holds two noticeable improvements in efficiency:
   1. Stream-wise temperature rise on the base of surface is substantially reduced compared to single-layer micro-channels.
   2. Pressure drop required for the multi-layered heat sink is substantially smaller than the single-layer design.
   3. Size of coolant pumping system is reduced.