Assessment of heat transfer and pressure drop of metal foam-pin-fin heat sink

2021 ◽  
Vol 170 ◽  
pp. 107109
Author(s):  
Mohanad A. Alfellag ◽  
Hamdi E. Ahmed ◽  
Mohammed Gh. Jehad ◽  
Marwan Hameed
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Metal Foam ◽  
Pin Fin

Numerical Analysis of Convective Heat Transfer From an Elliptic Pin Fin Heat Sink With and Without Metal Foam Insert

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Hamid Reza Seyf ◽  
Mohammad Layeghi
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Numerical Analysis ◽  
Pressure Drop ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Heat Sink ◽  
Metal Foam ◽  
Pin Fin

A numerical analysis of forced convective heat transfer from an elliptical pin fin heat sink with and without metal foam inserts is conducted using three-dimensional conjugate heat transfer model. The pin fin heat sink model consists of six elliptical pin rows with 3 mm major diameter, 2 mm minor diameter, and 20 mm height. The Darcy–Brinkman–Forchheimer and classical Navier–Stokes equations, together with corresponding energy equations are used in the numerical analysis of flow field and heat transfer in the heat sink with and without metal foam inserts, respectively. A finite volume code with point implicit Gauss–Seidel solver in conjunction with algebraic multigrid method is used to solve the governing equations. The code is validated by comparing the numerical results with available experimental results for a pin fin heat sink without porous metal foam insert. Different metallic foams with various porosities and permeabilities are used in the numerical analysis. The effects of air flow Reynolds number and metal foam porosity and permeability on the overall Nusselt number, pressure drop, and the efficiency of heat sink are investigated. The results indicate that structural properties of metal foam insert can significantly influence on both flow and heat transfer in a pin fin heat sink. The Nusselt number is shown to increase more than 400% in some cases with a decrease in porosity and an increase in Reynolds number. However, the pressure drop increases with decreasing permeability and increasing Reynolds number.

Heat Transfer and Pressure Drop in a Pin Fin Heat Sink Using Nanofluids as Coolant

2015 ◽  
Vol 1105 ◽  
pp. 253-258 ◽  
Author(s):  
Weerapun Duangthongsuk ◽  
Somchai Wongwises
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Heat Transfer Performance ◽  
Working Fluid ◽  
Electric Heater ◽  
Uniform Heat Flux ◽  
Heat Transfer Area ◽  
Pin Fin ◽  
Aluminum Material

This research presents an experimental investigation on the heat transfer performance and pressure drop characteristics of a heat sink with miniature square pin fin structure using nanofluids as coolant. ZnO-water nanofluids with particle concentrations of 0.2, 0.4 and 0.6 vol.% are used as working fluid and then compared with the data for water-cooled heat sink. Heat sink made from aluminum material with dimension around 28 x 33 x 25 mm (width x length x thickness). The heat transfer area and hydraulic diameter of the each flow channel is designed at 1,565 mm2and 1.2 mm respectively. Uniform heat flux at the bottom of heat sink is achieved using an electric heater. The experimental data illustrate that the thermal performance of heat sink using nanofluids as coolant is average 14% higher than that of the water-cooled heat sink. For pressure drop, the data show that the pressure drop of nanofluids is a few percent larger than that of the water-cooled heat sink.

Cryogenic Single-Phase Heat Transfer in a Microscale Pin Fin Heat Sink

2013 ◽  
Author(s):  
Eric D. Truong ◽  
Erfan Rasouli ◽  
Vinod Narayanan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Single Phase ◽  
Flow Direction ◽  
Heat Sinks ◽  
Variable Cross ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients

A combined experimental and computational fluid dynamics study of single-phase liquid nitrogen flow through a microscale pin-fin heat sink is presented. Such cryogenic heat sinks find use in applications such as high performance computing and spacecraft thermal management. A circular pin fin heat sink in diameter 5 cm and 250 micrometers in depth was studied herein. Unique features of the heat sink included its variable cross sectional area in the flow direction, variable pin diameters, as well as a circumferential distribution of fluid into the pin fin region. The stainless steel heat sink was fabricated using chemical etching and diffusion bonding. Experimental results indicate that the heat transfer coefficients were relatively unchanged around 2600 W/m2-K for flow rates ranging from 2–4 g/s while the pressure drop increased monotonically with the flow rate. None of the existing correlations in literature on cross flow over a tube bank or micro pin fin heat sinks were able to predict the experimental pressure drop and heat transfer characteristics. However, three dimensional simulations performed using ANSYS Fluent showed reasonable (∼7 percent difference) agreement in the average heat transfer coefficients between experiments and CFD simulations.

Optimization of Pin-Fin Heat Sinks in Bypass Flow Using Entropy Generation Minimization Method

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
W. A. Khan ◽  
J. R. Culham ◽  
M. M. Yovanovich
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Entropy Generation ◽  
Heat Sink ◽  
Heat Sinks ◽  
Entropy Generation Rate ◽  
Bypass Flow ◽  
Minimization Method ◽  
Pin Fin ◽  
Entropy Generation Minimization

An entropy generation minimization method is applied to study the thermodynamic losses caused by heat transfer and pressure drop for the fluid in a cylindrical pin-fin heat sink and bypass flow regions. A general expression for the entropy generation rate is obtained by considering control volumes around the heat sink and bypass regions. The conservation equations for mass and energy with the entropy balance are applied in both regions. Inside the heat sink, analytical/empirical correlations are used for heat transfer coefficients and friction factors, where the reference velocity used in the Reynolds number and the pressure drop is based on the minimum free area available for the fluid flow. In bypass regions theoretical models, based on laws of conservation of mass, momentum, and energy, are used to predict flow velocity and pressure drop. Both in-line and staggered arrangements are studied and their relative performance is compared to the same thermal and hydraulic conditions. A parametric study is also performed to show the effects of bypass on the overall performance of heat sinks.

Experimental Study of Pressure Drop and Heat Transfer in a Single-Phase Micropin-Fin Heat Sink

2007 ◽  
Vol 129 (4) ◽  
pp. 479-487 ◽  
Author(s):  
Abel Siu-Ho ◽  
Weilin Qu ◽  
Frank Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Heat Sink ◽  
Single Phase ◽  
Tip Clearance ◽  
Hydrodynamic Performance ◽  
Pin Fin ◽  
Heat Transfer Correlations

The pressure drop and heat transfer characteristics of a single-phase micropin-fin heat sink were investigated experimentally. Fabricated from 110 copper, the heat sink contained an array of 1950 staggered square micropin fins with 200×200μm2 cross section by 670μm height. The ratios of longitudinal pitch and transverse pitch to pin-fin equivalent diameter are equal to 2. De-ionized water was employed as the cooling liquid. A coolant inlet temperature of 25°C, and two heat flux levels, qeff″=50W∕cm2 and qeff″=100W∕cm2, defined relative to the platform area of the heat sink, were tested. The inlet Reynolds number ranged from 93 to 634 for qeff″=50W∕cm2, and from 127 to 634 for qeff″=100W∕cm2. The measured pressure drop and temperature distribution were used to evaluate average friction factor and local averaged heat transfer coefficient/Nusselt number. Predictions of the previous friction factor and heat transfer correlations that were developed for low Reynolds number (Re<1000) single-phase flow in short pin-fin arrays were compared to the present micropin-fin data. Moores and Joshi’s friction factor correlation (2003, “Effect of Tip Clearance on the Thermal and Hydrodynamic Performance of a Shrouded Pin Fin Array,” ASME J. Heat Transfer, 125, pp. 999–1006) was the only one that provided acceptable predictions. Predictions from the other friction factor and heat transfer correlations were significantly different from the experimental data collected in this study. These findings point to the need for further fundamental study of single-phase thermal/fluid transport process in micropin-fin arrays for electronic cooling applications.

Impact of Particulate Deposition on the Thermohydraulic Performance of Metal Foam Heat Exchangers: A Simplified Theoretical Model

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
K. Hooman ◽  
A. Tamayol ◽  
M. R. Malayeri
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Particle Deposition ◽  
Metal Foam ◽  
Cell Model ◽  
Heated Surface ◽  
Total Heat Transfer ◽  
Fluid Velocities ◽  
Deposit Layer

Assuming uniform particulate deposit layer, with deposition layer thickness in the range of 10–400 μm, on the ligaments of a metal foam heat sink, the effects of airborne particle deposition on the steady-state thermohydraulic performance of a metal foam heat sink are examined theoretically. Using a cubic cell model, changes in the foam internal structure, due to deposition, have been theoretically related to the increased pressure drop due to partial blockage of the pores. Our results suggest that the fouled to clean pressure drop ratio is only a function of the ligament to pore diameter ratio. Another interesting observation is that, compared to clean foams, the pressure drop can increase by orders of magnitude depending on the extent to which the pores are blocked. To examine the fouling effects on heat transfer from the foams, a thermal resistance network has been used. Moreover, the heat transfer from metal foams is more affected by fouling at higher fluid velocities. For example, when air is pushed through foams which their ligaments are uniformly covered by particles at 3 m/s, up to 15% decrease in the total heat transfer from the heated surface is predicted.

Pressure Drop and Heat Transfer in a Single-Phase Micro-Pin-Fin Heat Sink

2006 ◽  
Author(s):  
Abel M. Siu Ho ◽  
Weilin Qu ◽  
Frank Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Pressure Drop ◽  
Friction Factor ◽  
Heat Sink ◽  
Single Phase ◽  
Fluid Transport ◽  
Heat Sinks ◽  
Inlet Temperature ◽  
Pin Fin

The pressure drop and heat transfer characteristics of a single-phase micro-pin-fin heat sink were investigated experimentally. Fabricated from 110 copper, the heat sink consisted of 1950 staggered micro-pins with 200×200 μm2 cross-section by 670 μm height. Deionized water was employed as the cooling liquid. A coolant inlet temperature of 25°C, and two heat flux levels, q" eff = 50 W/cm2 and q" eff = 100 W/cm2, defined relative to the planform area of the heat sink, were tested. The inlet Reynolds number ranged from 93 to 634 for q" eff = 50 W/cm2, and 127 to 634 for q" eff = 100 W/cm2. The measured pressure drop and temperature distribution were used to evaluate average friction factor and local averaged heat transfer coefficient/Nusselt number. Predictions of the Moores and Joshi friction factor correlation and the Chyu et al. heat transfer correlation that were developed using macro-size pin-fin arrays were compared to micro-pin-fin heat sink data. While the Moores and Joshi correlation provide acceptable predictions, the Chyu et al. correlation overpredicted local Nusselt number data by a fairly large margin. These findings point to the need for further study of single-phase thermal/fluid transport process in micro-pin-fin heat sinks.

Numerical Analysis of Entropy Generation in Array of Pin-Fin Heat Sinks for Some Different Geometries

2010 ◽  
Author(s):  
Reza Kamali ◽  
Bamdad Barari ◽  
Ashkan Abbasian Shirazi
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Pressure Drop ◽  
Cross Section ◽  
Entropy Generation ◽  
Heat Sink ◽  
Control Volume ◽  
Heat Sinks ◽  
Entropy Generation Rate ◽  
Pin Fin

In this study, Numerical analysis has been used to investigate entropy generation for array of pin-fin heat sink. Technique is applied to study the thermodynamic losses caused by heat transfer and pressure drop in pin-fin heat sinks. A general expression for the entropy generation rate is obtained by considering the whole heat sink as a control volume and applying the conservation equations for mass and energy with the entropy balance. Analytical and empirical correlations for heat transfer coefficients and friction factors are used in the numerical modeling. Also effects of heat transfer and pressure drop in entropy generation in control volume over pin-fins have been studied. Numerical analysis has been used for three different models of pin-fin heat sinks. The models are different in cross section area. These cross section areas are circle, horizontal ellipse and vertical ellipse which mentioned in next sections. Reference velocity used in Reynolds number and pressure drop is based on the minimum free area available for the fluid flow. Also for numerical analysis in-line arrangement of fins has been investigated and their relative performance is compared. At the end, the performance of these three models has been compared.

Effect of variation of cylindrical pin fins height on the overall performance of microchannel heat sink

2019 ◽  
Vol 233 (5) ◽  
pp. 980-990 ◽  
Author(s):  
Mohammad Owais Qidwai ◽  
Mohammad Muzaffarul Hasan
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
High Efficiency ◽  
Rectangular Channel ◽  
Microchannel Heat Sink ◽  
Reduced Pressure ◽  
Number Range ◽  
Pin Fin ◽  
Downstream Region

Numerous researches are performed to take account of the heat transfer in the microchannel heat sink, due to its high efficiency and application in various fields of microelectronics. An attempt has been made to numerically investigate the effects of variation of cylindrical pin fin height, entrenched on bottom wall of microchannel. Three cases of microchannel heat sink are prepared: case 1: plain rectangular channel; case 2 and case 3 with decreasing pin fin height and with increasing pin fin height in the direction of flow, respectively. Also, diameter of pin fin is varied to obtain effects of any underlying flow feature on heat transfer augmentation. The analysis is performed for single-phase fluid deionized ultra-filtered water with temperature-dependent properties, for low Reynolds number range of 150–300. Higher Nusselt number is obtained for case 2, whereas lower pressure drop is obtained in case 3. The overall thermal performance of case 3 with increasing pin fin height outperforms the corresponding case 2 with decreasing pin fin height for the same pin fin diameter, due to the velocity distribution and reduced pressure drop in the downstream region in microchannel, which shows that the downstream region of microchannel heat sink has a significant impact in terms of the overall efficiency while establishing pressure drop as essential characteristics.

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