Single-Phase Forced Convection in Microchannels with Carbon Nanotubes for Electronics Cooling Applications

Abstract

A comparative experimental study was conducted to determine whether it would be advantageous to grow carbon nanotubes on the bottom surface of silicon microchannels to facilitate greater heat removal in electronics cooling applications. The performance was evaluated based on the surface temperature increase above the inlet coolant temperature and the pressure drop. The height and deposition pattern of the nanotubes were parameters investigated in this study. Water was passed through the microchannels at two volumetric flow rates of 2.7 × 10⁻⁷ m³/s and 4.7 × 10⁻⁷ m³/s. Additionally, two heat fluxes were applied to the back side of the microchannel (10 W/cm² and 30 W/cm²). For the devices tested, the samples with carbon nanotubes not only had a higher pressure drop but also had a higher surface temperature. Based on a continuum investigation, the increase in thermal performance gained by increasing the surface area is overshadowed by the decrease in mass flow rate for a fixed pressure drop.

KEY WORDS:

• carbon nanotube
• microchannel
• electronics cooling

The authors thank Samuel Graham, Jud Ready, and Stephan Turano for their help with carbon nanotube growth, Qihong Nie for assistance with numerical modeling, and Brent Buchine for assistance with scanning electron microscopy. Support from the National Science Foundation and Sandia National Laboratories, through grant CBET 0625865, is acknowledged.