Record number :
96217
Title of article :
Visualization and measurements of periodic boiling in silicon microchannels
Author/Authors :
Cheng، Ping نويسنده , , Wu، H. Y. نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2003
Pages :
-2602
From page :
2603
To page :
0
Abstract :
A simultaneous visualization and measurement investigation has been carried out on flow boiling of water in parallel silicon microchannels of trapezoidal cross-section. Two sets of parallel microchannels, having hydraulic diameters of 158.8 and 82.8 (mu)m, respectively, were used. The visualization study shows that once boiling heat transfer is established, two-phase flow and single-phase liquid flow appear alternatively with time in the microchannels. Large-amplitude/long-period fluctuations with time in wall temperatures, fluid temperatures, fluid pressures, and fluid mass flux, are measured for the first time during flow boiling in the microchannels. The fluctuation periods are found to be dependent on channel size, heat flux, and mass flux. The mechanism of the periodic boiling fluctuations in this experiment as well as their comparisons with other boiling fluctuations phenomena reported previously, are also discussed. The experimental results confirm that large-amplitude/long-period boiling fluctuations can be sustained when the fluctuations of pressure drop and mass flux have phase differences.With the aid of a microscope and high-speed video recording system, bubbly flow, slug flow, churn flow, and other peculiar flow patterns, are observed during two-phase flow periods in the microchannels.
Keywords :
instability , Microchannels , Boiling heat transfer
Journal title :
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
Journal title :
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
Serial Year :
2003
Link To Document :
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