On the Use of Micro Heat Pipes as an Integral Part of Semiconductor Devices

1992 ◽  
Vol 114 (4) ◽  
pp. 436-442 ◽  
Author(s):  
A. K. Mallik ◽  
G. P. Peterson ◽  
M. H. Weichold
Keyword(s):  
Numerical Model ◽  
Three Dimensional ◽  
Internal Heat ◽  
Heat Pipes ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Physical Parameters ◽  
Chip Temperature ◽  
Array Density ◽  
Micro Heat Pipes

A transient three-dimensional numerical model was developed to determine the potential advantages of constructing an array of very small (100 μm diameter) heat pipes as an integral part of semiconductor chips. Because of the high effective thermal conductivity, this array of heat pipes functions as a highly efficient heat spreader. The numerical model presented here, when given the physical parameters of the chip and the locations and magnitude of the internal heat generation, is capable of predicting the time dependent temperature distribution, localized heat flux, and temperature gradients occurring within the chip. The results of this modeling effort indicate that significant reductions in the maximum chip temperature, thermal gradients and localized heat fluxes can be obtained through the incorporation of arrays of micro heat pipes. Utilizing heat sinks located on the edges of the chip perpendicular to the axis of the heat pipes and an optimized array density of 1.35 percent, reductions in the maximum chip temperature of up to 40 percent were achieved.

Evaporation, Condensation, and Flow in an Idealized Micro Heat Pipe

2002 ◽  
Author(s):  
Jin Zhang ◽  
Harris Wong
Keyword(s):  
Thermal Conductivity ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Three Dimensional ◽  
Heat Pipes ◽  
Rigorous Analysis ◽  
Evaporation And Condensation ◽  
Micro Heat Pipe ◽  
Complicated Geometry ◽  
Micro Heat Pipes

Micro heat pipes have been used in cooling micro electronic components. However their effective thermal conductivity is low compared with that of conventional heat pipes. Due to the complexity of the coupled heat and mass transport, and to the complicated three-dimensional bubble geometry inside micro heat pipes, there is a lack of rigorous analysis. As a result, the relatively low effective thermal conductivity remains unexplained. We have conceptualized an idealized micro heat pipe that eliminates the complicated geometry, but retains the essential physics. Given the simplified geometry, many effects can be studied, such as thermocapillary flow, and evaporation and condensation physics. In this talk, we will present the flow field induced by evaporation.

Transient Multidimensional Analysis of Nonconventional Heat Pipes With Uniform and Nonuniform Heat Distributions

1991 ◽  
Vol 113 (4) ◽  
pp. 995-1002 ◽  
Author(s):  
Y. Cao ◽  
A. Faghri
Keyword(s):  
Heat Pipe ◽  
Three Dimensional ◽  
Leading Edge ◽  
Heat Pipes ◽  
High Heat ◽  
Heat Fluxes ◽  
Multidimensional Analysis ◽  
Vapor Flow ◽  
Operating Limits ◽  
Good Agreement

A numerical analysis of transient heat pipe performance including nonconventional heat pipes with nonuniform heat distributions is presented. A body-fitted grid system was applied to a three-dimensional wall and wick model, which was coupled with a transient compressible quasi-one-dimensional vapor flow model. The numerical results were first compared with experimental data from cylindrical heat pipes with good agreement. Numerical calculations were then made for a leading edge heat pipe with localized high heat fluxes. Performance characteristics different from conventional heat pipes are illustrated and some operating limits concerning heat pipe design are discussed.

Forced Convection Heat Transfer Enhancement by Porous Pin Fins in Rectangular Channels

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Jian Yang ◽  
Min Zeng ◽  
Qiuwang Wang ◽  
Akira Nakayama
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Convection Heat Transfer ◽  
Heat Fluxes ◽  
Physical Parameters ◽  
Pore Density ◽  
Pressure Drops ◽  
Pin Fin ◽  
Rectangular Channels ◽  
Pin Fins

The forced convective heat transfer in three-dimensional porous pin fin channels is numerically studied in this paper. The Forchheimer–Brinkman extended Darcy model and two-equation energy model are adopted to describe the flow and heat transfer in porous media. Air and water are employed as the cold fluids and the effects of Reynolds number (Re), pore density (PPI) and pin fin form are studied in detail. The results show that, with proper selection of physical parameters, significant heat transfer enhancements and pressure drop reductions can be achieved simultaneously with porous pin fins and the overall heat transfer performances in porous pin fin channels are much better than those in traditional solid pin fin channels. The effects of pore density are significant. As PPI increases, the pressure drops and heat fluxes in porous pin fin channels increase while the overall heat transfer efficiencies decrease and the maximal overall heat transfer efficiencies are obtained at PPI=20 for both air and water cases. Furthermore, the effects of pin fin form are also remarkable. With the same physical parameters, the overall heat transfer efficiencies in the long elliptic porous pin fin channels are the highest while they are the lowest in the short elliptic porous pin fin channels.

Analysis of Porous Wick Heat Pipes, Including Capillary Dry-Out Limitations

2005 ◽  
Author(s):  
Jeremy Rice ◽  
Amir Faghri
Keyword(s):  
Numerical Model ◽  
Capillary Pressure ◽  
Heat Pipes ◽  
Heat Sinks ◽  
Heat Sources ◽  
Numerical Work ◽  
Porous Wick ◽  
Heating Load ◽  
Capillary Pressures ◽  
Dry Out

A complete numerical analysis of heat pipes is performed with no empirical correlations while including the flow in a wick. The numerical model is validated from experimental and numerical work. Single and multiple heat sources were used as well as constant, convective and radiative heat sinks. The numerical model does not fix the internal pressure references by a point, but allows is to rise and fall based on the physics of the problem. Also, the capillary pressure needed in the wick to drive the flow is obtained for various heating configurations and powers. These capillary pressures, in conjunction with an analysis that predicts the maximum capillary pressure for a given heating load is used to determine the dry-out limitations of a heat pipe.

Broadband liner impedance eduction for multimodal acoustic propagation in the presence of a mean flow

2016 ◽  
Vol 11 (2) ◽  
pp. 150-155
Author(s):  
R. Troian ◽  
D. Dragna ◽  
C. Bailly ◽  
M.-A. Galland
Keyword(s):  
Numerical Model ◽  
Flow Characteristics ◽  
Acoustic Propagation ◽  
Rational Fraction ◽  
Physical Parameters ◽  
Mean Flow ◽  
Linearized Euler Equations ◽  
Grazing Flow ◽  
Propagation Medium ◽  
Difference Time

Modeling of acoustic propagation in a duct with absorbing treatment is considered. The surface impedance of the treatment is sought in the form of a rational fraction. The numerical model is based on a resolution of the linearized Euler equations by finite difference time domain for the calculation of the acoustic propagation under a grazing flow. Sensitivity analysis of the considered numerical model is performed. The uncertainty of the physical parameters is taken into account to determine the most influential input parameters. The robustness of the solution vis-a-vis changes of the flow characteristics and the propagation medium is studied.

A THREE-DIMENSIONAL NUMERICAL MODEL FOR SELECTIVE WITHDRAWAL IN COASTAL AREA

2018 ◽  
Vol 74 (5) ◽  
pp. I_571-I_576
Author(s):  
Yasuo NIIDA ◽  
Norikazu NAKASHIKI ◽  
Takaki TSUBONO ◽  
Shin’ichi SAKAI ◽  
Teruhisa OKADA
Keyword(s):  
Numerical Model ◽  
Coastal Area ◽  
Three Dimensional ◽  
Selective Withdrawal
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