Numerical Investigation of Thermofluid Flow Characteristics With Phase Change Against High Heat Flux in Porous Media

2005 ◽  
Author(s):  
K. Yuki ◽  
J. Abei ◽  
H. Hashizume ◽  
S. Toda
Keyword(s):  
Heat Flux ◽  
Solid Phase ◽  
Flow Characteristics ◽  
High Heat ◽  
Energy Model ◽  
High Heat Flux ◽  
Phase Flow ◽  
Two Phase ◽  
Thermal Nonequilibrium ◽  
Flow Case

This study numerically evaluates thermofluid flow characteristics in porous media by a newly developed “modified two-phase mixture model” applying a two-energy model instead of an one-energy model. In a single-phase flow case, thermal nonequilibrium between a solid phase and a fluid phase is observed in the area where inlet heat conducts from a heating wall and further convective heat transfer is more active. Though the degree of thermal nonequilibrium has a positive correlation with the increase in flow velocity and inlet heat flux, the degree is very low and can be ignored, from an engineering perspective. In a case of two-phase flow, the thermal nonequilibrium is remarkable in the two-phase region because the solid-phase temperature in this region is far beyond saturation temperature. A difference between these two models is obvious especially in the two-phase flow case, so that the numerical simulation with the two-energy model is indispensable under the high heat flux conditions of over 1MW/m2.

Numerical Investigation of Thermofluid Flow Characteristics With Phase Change Against High Heat Flux in Porous Media

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Kazuhisa Yuki ◽  
Jun Abei ◽  
Hidetoshi Hashizume ◽  
Saburo Toda
Keyword(s):  
Heat Flux ◽  
Solid Phase ◽  
Flow Characteristics ◽  
High Heat ◽  
High Heat Flux ◽  
Phase Flow ◽  
Two Phase ◽  
Thermal Nonequilibrium ◽  
Phase Mixture ◽  
Flow Case

This study numerically evaluates thermofluid flow characteristics in porous medium by a newly developed “modified two-phase mixture model” applying Ergun’s law and a two-energy model instead of a one-energy model. In a single-phase flow case, thermal nonequilibrium between a solid phase and a fluid phase is observed in the area where imposed heat conducts from a heating wall and further convective heat transfer is more active. The degree of thermal nonequilibrium has a positive correlation with the increase in flow velocity and heat flux input. In the case of two-phase flow, the thermal nonequilibrium is remarkable in the two-phase region because the solid-phase temperature in this region is far beyond saturation temperature. A difference between these two models is obvious especially in the two-phase flow case, so that the numerical simulation with the modified two-phase mixture model is indispensable under the high heat flux conditions of over 1MW∕m2.

State of the Art of Electronics Cooling for Radar Antenna Applications

2017 ◽  
Author(s):  
Girish Upadhya ◽  
Clayton Pullins ◽  
Karl Freitag ◽  
George Hall ◽  
James Marthinuss
Keyword(s):  
Heat Flux ◽  
Two Phase Flow ◽  
Electronic Device ◽  
High Heat ◽  
Thermal Design ◽  
High Heat Flux ◽  
Phase Flow ◽  
Two Phase ◽  
Modeling Tools ◽  
Radar Antenna

High heat flux from electronic devices remains a continuing challenge for cooling of electronics hardware in radar antenna applications pertaining to the defense industry. Cooling methods for such applications have varied from conduction cooling approaches for the cooling of circuit card assemblies, to advanced convection cooling using two phase flow (with pumped refrigerant) for the high heat flux devices used in transmit / receive modules. It is found that the limiting parameter in such applications is usually the heat flux from the electronic device. This paper provides an overview of the cooling techniques used for defense electronics, as well as current modeling tools and analytical methods used for thermal design during the product development phase. The role of thermal interface materials used in the material stack up for the thermal design solutions will also be touched upon. Additionally, the importance of using experimental techniques to characterize the heat transfer coefficient for the pumped refrigerant two phase flow will be discussed.

A Review of High-Heat-Flux Heat Removal Technologies

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
M. A. Ebadian ◽  
C. X. Lin
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flow Boiling ◽  
Heat Removal ◽  
High Heat ◽  
High Heat Flux ◽  
Phase Flow ◽  
Two Phase ◽  
Recent Developments ◽  
Removal Technologies

In recent years, high-heat-flux cooling techniques have received great attention from researchers around the world due to its importance in thermal management of both commercial and defense high-power electronic devices. Although impressive progress has been made during the last few decades, high-heat-flux removal still largely remains as a challenging subject that needs further exploration and study. In this paper, we have reviewed recent developments in several high-heat-flux heat removal techniques, including microchannels, jet impingements, sprays, wettability effects, and piezoelectrically driven droplets. High-heat-flux removal can be achieved effectively by either single-phase flow or two-phase flow boiling heat transfer. Better understandings of the underlying heat transfer mechanisms for performance improvement are discussed.

Reliable MOSFET operation using two-phase microfluidics in the presence of high heat flux transients

2011 ◽  
Vol 21 (10) ◽  
pp. 105002 ◽  
Author(s):  
Shiv Govind Singh ◽  
Amit Agrawal ◽  
Siddhartha P Duttagupta
Keyword(s):  
Heat Flux ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase
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