04/03113 Measurement and correlation of critical heat flux in two-phase micro-channel heat sinks

2004 ◽  
Vol 45 (6) ◽  
pp. 437
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Heat Sinks ◽  
Micro Channel ◽  
Two Phase

Constrained Optimization of One-Dimensional Two-Phase Flow in Fractal-Like Branching Microchannel Heat Sinks

2011 ◽  
Author(s):  
Douglas B. Heymann ◽  
Deborah V. Pence
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Wall Temperature ◽  
Two Phase Flow ◽  
Heat Sinks ◽  
Phase Flow ◽  
Two Phase ◽  
One Dimensional ◽  
Temperature Constraint ◽  
Flow Through

The performance of two-phase flow through fractal-like heat sinks, subject to both geometrical and flow constraints was assessed. Constraints are crucial in order to satisfy physical requirements of a design. A one-dimensional model of two-phase flow through fractal-like branching microchannels was used to estimate pressure drop, wall temperature and critical heat flux. Water is employed as the working fluid. The exit pressure is varied between 6 kPa and 101.3 kPa (absolute) in order to achieve two-phase flow at temperatures lower than the maximum wall temperature constraint of 70°C. Preliminary results show that the benefit to cost ratio of two-phase flow is on the same order of magnitude as single-phase flow, both with a 70°C wall temperature constraint. Alternatively, a critical heat flux model is used to constrain the flow rate in order for the imposed heat flux to be 50% of the critical heat flux.

Convective Boiling in Parallel Micro-Channels

2003 ◽  
Author(s):  
G. Hetsroni ◽  
D. Klein ◽  
A. Mosyak ◽  
Z. Segal ◽  
E. Pogrebnyak
Keyword(s):  
Heat Flux ◽  
High Speed ◽  
Heat Sinks ◽  
Micro Channel ◽  
Clear Water ◽  
Two Phase ◽  
Convective Boiling ◽  
Flow Rates ◽  
Micro Channels ◽  
Infrared Radiometry

Experiments were performed with clear water and with surfactant flowing in parallel triangular micro-channels. The study is based on systematic measurements of temperature and flow pattern by infrared radiometry and high-speed digital video imaging. Different flow patterns were observed simultaneously in various micro-channels at a fixed value of water or surfactant flow rates. Depending on flow and heat flux, pressure and temperature instabilities in the heated micro-channels were studied. This work develops a practical modeling approach for two-phase micro-channel heat sinks and considers also effect of surfactant on convective boiling in micro-channels.

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