Flow Boiling Heat Transfer to a Dielectric Coolant in a Microchannel Heat Sink

Abstract

This paper presents an experimental study of flow boiling heat transfer in a microchannel heat sink. The dielectric fluid Fluorinert FC-77 is used as the boiling liquid after it is fully degassed. The experiments were performed at three flow rates ranging from 30 to 50 ml/min. The heat transfer coefficients, as well as the critical heat flux, were found to increase with flow rate. Wall temperature measurements at three locations (near the inlet, near the exit, and in the middle of heat sink) reveal that wall dryout first occurs near the exit of the microchannels. The ratio of heat transfer rate under critical heat flux conditions to the limiting evaporation rate was found to decrease with increasing flow rate, asymptotically approaching unity. Predictions from a number of correlations for nucleate boiling heat transfer in the literature are compared against the experimental results to identify those that provide a good match. The results of this work provide guidelines for the thermal design of microchannel heat sinks in two-phase flow.

Flow Boiling in Silicon Microchannel Heat Sinks

“…Other microchannel sizes tested yielded similar trends for the dependence of boiling curves and the heat transfer coefficient on mass flux. The influence of mass flux on boiling curves is consistent with the results of Chen and Garimella [5], Liu and Garimella [20], and Pate et al [21], Chen and Garimella [4,5] also obtained similar results for the dependence of heat transfer coefficient on the flow rate.…”

“…Three different flow rates were tested and high-speed visualizations performed. In companion work [5], they also studied the effect of flow rate on the flow boiling of FC-77 in a copper microchannel heat sink.…”

“…Although a large number of studies of microchannel flow boiling have been reported, few have explored the effect of microchannel dimensions [16,17,18,19] and mass flux [4,5,20.21] on the flow patterns and heat transfer characteristics.…”

Integrated Liquid Cooling Systems for 3-D Stacked TSV Modules

“…The effect of the microchannel geometry on the temperature distribution in the microchannel heat sink is presented and discussed assuming a constant pumping power [12]. Chen and Garimella presented an experimental study of two-phase heat transfer in a microchannel heat sink and to provide guidelines for the thermal design of microchannel heat sinks in two-phase flow [13]. More recently, Lee and Mudawar explored the benefits of cooling the device using direct and indirect refrigeration cooling systems.…”