Forced Convection in a Porous Channel With Localized Heat Sources

1994 ◽  
Vol 116 (2) ◽  
pp. 465-472 ◽  
Author(s):  
A. Hadim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Pressure Drop ◽  
Heat Source ◽  
Forced Convection ◽  
Numerical Study ◽  
Porous Channel ◽  
Heat Sources ◽  
Porous Layers ◽  
Channel Configuration

A numerical study is performed to analyze steady laminar forced convection in a channel filled with a fluid-saturated porous medium and containing discrete heat sources on the bottom wall. Hydrodynamic and heat transfer results are reported for two configurations: (1) a fully porous channel, and (2) a partially porous channel, which contains porous layers above the heat sources and is nonporous elsewhere. The flow in the porous medium is modeled using the Brinkman-Forchheimer extended Darcy model. Heat transfer rates and pressure drop are evaluated for wide ranges of Darcy and Reynolds numbers. Detailed results of the evolution of the hydrodynamic and thermal boundary layers are also provided. The results indicate that as the Darcy number decreases, a significant increase in heat transfer is obtained, especially at the leading edge of each heat source. For fixed Reynolds number, the length-averaged Nusselt number reaches an asymptotic value in the Darcian regime. In the partially porous channel, it is found that when the width of the heat source and the spacing between the porous layers are of the same magnitude as the channel height, the heat transfer enhancement is almost the same as in the fully porous channel while the pressure drop is significantly lower. These results suggest that the partially porous channel configuration is a potentially attractive heat transfer augmentation technique for electronic equipment cooling, an end that motivated this study.

Numerical Study of Forced Convection in a Partially Porous Channel With Discrete Heat Sources

1995 ◽  
Vol 117 (1) ◽  
pp. 46-51 ◽  
Author(s):  
H. A. Hadim ◽  
A. Bethancourt
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Pressure Drop ◽  
Heat Source ◽  
Heat Transfer Enhancement ◽  
Forced Convection ◽  
Numerical Study ◽  
Heat Sources ◽  
Transfer Enhancement ◽  
Discrete Heat Sources

A numerical study was performed to analyze steady laminar forced convection in a channel partially filled with a fluid-saturated porous medium and containing discrete heat sources on the bottom wall. Hydrodynamic and heat transfer results are reported for the configuration in which the porous layers are located above the heat sources while the rest of the channel is nonporous. The flow in the porous medium was modeled using the Brinkman-Forchheimer extended Darcy model. Parametric studies were conducted to evaluate the effects of variable heat source spacing and heat source width on heat transfer enhancement and pressure drop in the channel. The results indicate that when the heat source spacing was increased within the range considered, there was a negligible change in heat transfer enhancement while the pressure drop decreased significantly. When the heat source width was decreased, there was a moderate increase in heat transfer enhancement and a significant decrease in pressure drop.

Finned Metal Foam Heat Sinks for Electronics Cooling in Forced Convection

2002 ◽  
Vol 124 (3) ◽  
pp. 155-163 ◽  
Author(s):  
A. Bhattacharya ◽  
R. L. Mahajan
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Transfer Coefficient ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Forced Convection ◽  
Metal Foam ◽  
Experimental Results ◽  
Heat Sinks ◽  
The Heat Transfer Coefficient

In this paper, we present recent experimental results on forced convective heat transfer in novel finned metal foam heat sinks. Experiments were conducted on aluminum foams of 90 percent porosity and pore size corresponding to 5 PPI (200 PPM) and 20 PPI (800 PPM) with one, two, four and six fins, where PPI (PPM) stands for pores per inch (pores per meter) and is a measure of the pore density of the porous medium. All of these heat sinks were fabricated in-house. The forced convection results show that heat transfer is significantly enhanced when fins are incorporated in metal foam. The heat transfer coefficient increases with increase in the number of fins until adding more fins retards heat transfer due to interference of thermal boundary layers. For the 20 PPI samples, this maximum was reached for four fins. For the 5 PPI heat sinks, the trends were found to be similar to those for the 20 PPI heat sinks. However, due to larger pore sizes, the pressure drop encountered is much lower at a particular air velocity. As a result, for a given pressure drop, the heat transfer coefficient is higher compared to the 20 PPI heat sink. For example, at a Δp of 105 Pa, the heat transfer coefficients were found to be 1169W/m2-K and 995W/m2-K for the 5 PPI and 20 PPI 4-finned heat sinks, respectively. The finned metal foam heat sinks outperform the longitudinal finned and normal metal foam heat sinks by a factor between 1.5 and 2, respectively. Finally, an analytical expression is formulated based on flow through an open channel and incorporating the effects of thermal dispersion and interfacial heat transfer between the solid and fluid phases of the porous medium. The agreement of the proposed relation with the experimental results is promising.

Analysis of combined radiation and convection heat transfer inside a porous medium with heat source electronic devices

2022 ◽  
pp. 095440622110467
Author(s):  
Ali Mokhtari Nahal ◽  
Mohammad Hassan Nobakhti ◽  
Cyrus Aghanajafi ◽  
Morteza Khayat
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Source ◽  
Cooling Rate ◽  
Numerical Study ◽  
Electronic Devices ◽  
Convection Heat Transfer ◽  
Darcy Number ◽  
Flow Lines ◽  
Rayleigh Numbers

In this study, a numerical study is performed on the cooling phenomenon of three heat source electronic devices. The electronic devices are cooled in the form of natural heat transfer by the airflow in a porous medium. Electronic devices are installed on the boundary walls of a square environment. Cooling simulations are performed by drawing flow lines and constant temperature lines. Our main goal is to find the highest cooling rate in different Darcy numbers and different Rayleigh numbers in our investigation. The range of Darcy numbers and Rayleigh numbers is between 0.0001 to 0.01 and 1000 to 100,000, respectively. Our investigation showed the maximum cooling is obtained at the Darcy number of about 0.01. And also, by decreasing the value of Darcy number, a higher cooling rate for the hot boundary walls is achieved.

Numerical Study of Pulsating Flow Frequency and Heat Transfer in Porous Channel Heat Sink

2013 ◽  
Vol 455 ◽  
pp. 470-473
Author(s):  
Chao Wang ◽  
Shang Long Xu ◽  
Yun Chuan Wu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Numerical Study ◽  
Porous Channel ◽  
Channel Network ◽  
Temperature Distributions ◽  
Constant Wall Heat Flux ◽  
Flow Through

A study has been conducted on the heat transfer of various oscillatory frequencies of pulsation flow through a porous channel network subjected to a constant wall heat flux. The surface temperature distributions, pressure drop, unit thermal resistance and local Nusselt number for different oscillatory frequencies were mainly investigated.

scholarly journals Forced Convection through Discrete Heat Sources and Simple Thermal Model – A Numerical Study

2019 ◽  
Vol 4 (6) ◽  
pp. 1397-1406
Author(s):  
Kartikaswami Hasavimath ◽  
Kishan Naik ◽  
Banjara Kotresha ◽  
N. Gnanasekaran
Keyword(s):  
Heat Source ◽  
Forced Convection ◽  
Thermal Model ◽  
Conjugate Heat Transfer ◽  
Numerical Study ◽  
Vertical Channel ◽  
Heat Sources ◽  
Discrete Heat Sources ◽  
Discrete Heat Source ◽  
Bottom Heat

In this work a forced convection through discrete heat sources and simple thermal model placed inside the vertical channel is analyzed numerically. The problem considered for the investigation comprises of a vertical channel with distinct heat source assembly located at the center of the channel. The novelty of the present work is to replace the discrete heat source assembly by a simple thermal model to obtain uniformly distributed temperature and streamlines. A conjugate heat transfer investigation is carried out because the problem domain consists of aluminum solid strips as well as Bakelite strips in discrete heat source assembly which are replaced by a aluminum solid in case of simple thermal model. The numerically obtained data are initially compared with experimental data for the purpose of validation. The temperature of each discrete sources decrease with increase in inlet velocity of the fluid and bottom heat source is able to take higher heat load. The results in terms excess temperature obtained for both discrete heat source and simple thermal model is presented and discussed.

Single- and Two-Phase Convective Heat Transfer From Smooth and Enhanced Microelectronic Heat Sources in a Rectangular Channel

1989 ◽  
Vol 111 (4) ◽  
pp. 1045-1052 ◽  
Author(s):  
D. E. Maddox ◽  
I. Mudawar
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Heat Source ◽  
Convective Heat Transfer ◽  
Forced Convection ◽  
Convective Heat ◽  
Single Phase ◽  
Rectangular Channel ◽  
Heat Sources ◽  
Two Phase

Experiments have been performed to assess the feasibility of cooling microelectronic components by means of single-phase and two-phase forced convection. Tests were conducted using a single heat source flush mounted to one wall of a vertical rectangular channel. An inert fluorocarbon liquid (FC-72) was circulated upward through the channel at velocities up to 4.1 m/s and with subcooling up to 46°C. The simulated microelectronic heat sources tested in this study include a smooth surface and three low-profile microstud surfaces of varying stud height, each having a base area of 12.7×12.7 mm2. Correlations were developed for the single-phase convective heat transfer coefficient over the Reynolds number range from 2800 to 1.5 × 105, where Reynolds number is based on the length of the heater. The results demonstrate that the low thermal resistances required for cooling of microelectronic heat sources may be achieved with single-phase forced convection by using high fluid velocity coupled with surface enhancement. Experiments were also performed to understand better the parametric trends of boiling heat transfer from the simulated microelectronic heat source. It was found that increased velocity and subcooling and the use of microstud surfaces enhance nucleate boiling, increase the critical heat flux, and reduce the magnitude of temperature overshoot upon the inception of nucleation.

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