Two-phase microfluidic heat sinks promise high heat flux cooling at reduced pumping power compared to pumped liquid microchannel heat sinks. However, flow instabilities caused by bubble nucleation and expansion severely reduce heat transfer performance of two-phase microfluidic heat sinks. This study probes the governing physics of bubble nucleation and expansion by comparing the effects of pulsed heating to steady-state heating in a single microchannel. Pulsed heating at 8 Hz causes an increase in the average hotspot temperature of as much as 8°C compared to steady-state heating. Upstream and downstream temperature response does not vary significantly between heating conditions. The results correspond well with thin-film evaporation models for bubble growth. This study provides insight for designing two-phase microfluidic cooling system subjected to transient hotspots.

Volume Subject Area:
Thermal Management - Component Level Thermal Management
Topics:
Heat exchangers, Microchannels, Transient heat transfer, Two-phase flow, Heating, Bubbles, Heat sinks, Microfluidics, Nucleation (Physics), Steady state, Temperature, Cooling, Cooling systems, Design, Evaporation, Flow instability, Heat flux, Heat transfer, Physics, Probes, Thin films, Transients (Dynamics)
This content is only available via PDF.
Copyright © 2009
 by ASME
You do not currently have access to this content.