scholarly journals Mathematical Extrapolating of Highly Efficient Fin Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Thermal Efficiency ◽  
Dissipation Rate ◽  
High Performance ◽  
Heat Dissipation ◽  
Numerical Solutions ◽  
Pin Fin ◽  
Pin Fins ◽  
Effective Efficiency ◽  
Triangular Fin ◽  
Profile Area

Different high-performance fins are mathematically analyzed in this work. Initially, three types are considered: (i) exponential, (ii) parabolic, and (iii) triangular fins. Analytical solutions are obtained. Accordingly, the effective thermal efficiency and the effective volumetric heat dissipation rate are calculated. The analytical results were validated against numerical solutions. It is found that the triangular fin has the maximum effective thermal length. In addition, the exponential pin fin is found to have the largest effective thermal efficiency. However, the effective efficiency for the straight one is the maximum when its effective thermal length based on profile area is greater than 1.4. Furthermore, the exponential straight fin is found to have effective volumetric heat dissipation that can be 440% and 580% above the parabolic and triangular straight fins, respectively. In contrast, the exponential pin fin is found to possess effective volumetric heat dissipation that can be 120% and 132% above the parabolic and triangular pin fins, respectively. Finally, new high performance fins are mathematically generated that can have effective volumetric heat dissipation of 24% and 12% above those of exponential pin and straight fins, respectively.

Compact Transient Thermal Model of Microfluidically Cooled Three-Dimensional Stacked Chips With Pin-Fin Enhanced Microgap

2021 ◽  
Vol 143 (3) ◽  
Author(s):  
Yuanchen Hu ◽  
Md Obaidul Hossen ◽  
Zhimin Wan ◽  
Muhannad S. Bakir ◽  
Yogendra Joshi
Keyword(s):  
Heat Transfer ◽  
Integrated Circuit ◽  
High Performance ◽  
Heat Dissipation ◽  
Three Dimensional ◽  
Heat Removal ◽  
Power Estimation ◽  
Leakage Power ◽  
Pin Fin ◽  
Pin Fins

Abstract Three-dimensional (3D) stacked integrated circuit (SIC) chips are one of the most promising technologies to achieve compact, high-performance, and energy-efficient architectures. However, they face a heat dissipation bottleneck due to the increased volumetric heat generation and reduced surface area. Previous work demonstrated that pin-fin enhanced microgap cooling, which provides fluidic cooling between layers could potentially address the heat dissipation challenge. In this paper, a compact multitier pin-fin single-phase liquid cooling model has been established for both steady-state and transient conditions. The model considers heat transfer between layers via pin-fins, as well as the convective heat removal in each tier. Spatially and temporally varying heat flux distribution, or power map, in each tier can be modeled. The cooling fluid can have different pumping power and directions for each tier. The model predictions are compared with detailed simulations using computational fluid dynamics/heat transfer (CFD/HT). The compact model is found to run 120–600 times faster than the CFD/HT model, while providing acceptable accuracy. Actual leakage power estimation is performed in this codesign model, which is an important contribution for codesign of 3D-SICs. For the simulated cases, temperatures could decrease 3% when leakage power estimation is adopted. This model could be used as electrical-thermal codesign tool to optimize thermal management and reduce leakage power.

Effect of Heat Sink Structure Improvement on Heat Dissipation Performance in High Heat Flux

2016 ◽  
Author(s):  
Zhuo Cui
Keyword(s):  
Heat Resistance ◽  
Water Flow ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Convection Heat Transfer ◽  
Cooling Water ◽  
High Heat Flux ◽  
Pin Fin ◽  
Pin Fins ◽  
Pin Fin Arrays

This paper presents the effects of heat dissipation performance of pin fins with different heat sink structures. The heat dissipation performance of two types of pin fin arrays heat sink are compared through measuring their heat resistance and the average Nusselt number in different cooling water flow. The temperature of cpu chip is monitored to determine the temperature is in the normal range of working temperature. The cooling water flow is in the range of 0.02L/s to 0.15L/s. It’s found that the increase of pin fins in the corner region effectively reduce the temperature of heat sink and cpu chip. The new type of pin fin arrays increase convection heat transfer coefficient and reduce heat resistance of heat sink.

Numerical Analysis of Flat Plate Solar Air Heater Integrated With an Array of Pin Fins on Absorber Plate for Enhancement in Thermal Performance

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
M. S. Manjunath ◽  
K. Vasudeva Karanth ◽  
N. Yagnesh Sharma
Keyword(s):  
Numerical Analysis ◽  
Flat Plate ◽  
Flow Rate ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Pin Fin ◽  
Pin Fins ◽  
Effective Efficiency ◽  
Pin Fin Array ◽  
Lower Flow Rate

This paper presents a three-dimensional numerical analysis of a flat plate solar air heater in the presence of a pin fin array using the computational fluid dynamics (CFD) software tool ansys fluent 16.2. The effect of geometric parameters of pin fins as well as the flow Reynolds number (4000–24,000) on the effective efficiency is evaluated. The longitudinal pitch (PL) of pin fin array is varied as 30 mm, 40 mm, and 50 mm and the diameter (Dw) is varied as 1.0 mm, 1.6 mm, and 2.2 mm. The results show that the presence of pin fins generate considerable enhancement in fluid turbulence as well as heat transfer area to a maximum extent of about 53.8%. The maximum average increase in instantaneous thermal efficiency is found to be about 14.2% higher as compared with the base model for the fin diameter of 2.2 mm and a longitudinal pitch value of 30 mm. In terms of effective efficiency, the pin fin array exhibits significant enhancement, especially at lower flow rate conditions. Finally, the effective efficiency of the pin fin array is compared with the previous work of authors involving spherical turbulators and sinewave corrugations on the absorber plate. The results show that the pin fin array exhibits a relatively superior effective efficiency to a maximum extent of about 73% for lower flow rate conditions.

Orthotropic Thermal Conductivity Effect on Cylindrical Pin Fin Heat Transfer

2005 ◽  
Author(s):  
Raj Bahadur ◽  
Avram Bar-Cohen
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
High Performance ◽  
Heat Sinks ◽  
Transfer Coefficients ◽  
Design And Optimization ◽  
Pin Fin ◽  
Wide Range ◽  
Pin Fins ◽  
The One

There is growing interest in the use of polymer composites with enhanced thermal conductivity for high performance fin arrays and heat sinks. However, the thermal conductivity of these materials is relatively low compared to conventional fin metals, and strongly orthotropic. Therefore, the design and optimization of such polymer pin fins requires extension of the one dimensional classical fin analysis to include two-dimensional orthotropic heat conduction effects. An analytical equation for heat transfer from a cylindrical pin fin with orthotropic thermal conductivity is derived and validated using detailed finite-element results. The thermal performance of such fins was found to be dominated by the axial thermal conductivity, but to depart from the classical fin solution with increasing values of a radius- and radial conductivity-based Biot number. Using these relations, it is determined that fin orthotropy does not materially affect the behavior of typical air-cooled fins. Alternatively, for heat transfer coefficients achievable with water cooling and conductivity ratios below 0.1, the fin heat transfer rate can fall more than 25% below the “classical” heat transfer rates. Detailed orthotropic fin temperature distributions are used to explain this discrepancy. Simplified orthotropic pin fin heat transfer equations are derived and validated over a wide range of orthotropic conditions.

scholarly journals Numerical Research on Thermal Variations along SSF Pin Fins Shaped with SSM Processing

2019 ◽  
Vol 8 (12) ◽  
pp. 504-507
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Flux ◽  
Stainless Steel ◽  
Heat Dissipation ◽  
Heat Sinks ◽  
Pin Fin ◽  
Temperature Distributions ◽  
Pin Fins ◽  
Numerical Research

Fins or heat sinks are meant for boosting heat transfer. Therefore, planned computations remain fortified for examining the impacts of SSF pin fin on thermal dispersal concerning constant thermal value 6 W/cm2 . For that SSF pin fins materials of stainless steel and aluminum are preferred. Usual convective equations are solved to foretell thermal apprehensions. As anticipated, for both the stated SSF pin fins, temperature and heat flux declines for increasing length scales. Additionally, temperature distributions on SSF aluminum pin fin lays beneath SSF stainless steel pin fin. Hence, heat dissipation from SSF aluminum pin fin is relatively higher. Obviously, it may be owing to quite higher thermal conductivity of SSF aluminum pin fin. Consequently, it delivers higher, gregarious and remarkable thermal behaviors. Nevertheless, both simulation forecasts remain analogous with one another.

scholarly journals Thermal Characterizations of Exponential Fin Systems

2010 ◽  
Vol 2010 ◽  
pp. 1-19 ◽  
Author(s):  
A.-R. A. Khaled
Keyword(s):  
Thermal Performance ◽  
Thermal Efficiency ◽  
Performance Indicators ◽  
Cross Sectional ◽  
Pin Fin ◽  
Pin Fins

Exponential fins are mathematically analyzed in this paper. Two types are considered: (i) straight exponential fins and (ii) pin exponential fins. The possibility of having increasing or decreasing cross-sectional areas is considered. Different thermal performance indicators are derived. The maximum ratio between the thermal efficiency of the exponential straight fin to that of the rectangular fin is found to be 1.58 at an effective thermal length of 2.0. This ratio is even larger when exponential fins are compared with triangular and parabolic straight fins. Moreover, the maximum ratio between the thermal efficiency of the exponential pin fin to that of the rectangular pin fin is found to be 1.17 at an effective thermal length of 1.5. However, exponential pin fins thermal efficiencies are found to be lower than those of triangular and parabolic pin fins. Moreover, exponential joint-fins may transfer more heat than rectangular joint-fins especially when differences between their senders and receivers portions dimensionless indices are very large. Finally, it is found that increasing the joint-fin exponential index may cause straight exponential joint-fins to transfer more heat than rectangular joint-fins.

Comparative Analysis of Heat Transfer and Fluid Flow in Circular and Rhombus Pin Fin Heat Sink Using Nanofluid

2021 ◽  
Vol 13 (5) ◽  
Author(s):  
Dungali Sreehari ◽  
Yogesh K. Prajapati
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Comparative Analysis ◽  
Pressure Drop ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Flow Behavior ◽  
Computational Domain ◽  
Pin Fin ◽  
Pin Fins

Abstract Numerical investigation has been carried out to compare the heat transfer performance and fluid flow behavior of microchannel heat sinks with circular and rhombus pin fins which are arranged in an in-line manner. Diameter and sides are 1 mm for circular and rhombus fins. Three-dimensional (3D) computational domain has been simulated using two types of cooling medium, i.e., water and Al2O3–H2O nanofluid. A comprehensive comparative analysis has been presented considering the coolants and pin fin profiles as variable parameters. Two operating variables, i.e., heat flux (q) and Reynolds number (Re), are varied in the range of q = 100–400 kW/m2 and Re = 100–400. A total of 64 cases have been simulated to identify the promising features of both the pin fins attributed to improved heat transfer and overall thermal performance. Comparison has also been made between the coolant medium to find out their heat dissipation potential and flow characteristics in the heat sink. Results obtained in terms of average bottom wall temperature, heat transfer coefficient, Nusselt number (Nu), and pressure drop demonstrate that heat sink with rhombus pin fins dissipates more heat compared to its counterpart. It is attributed to the shape and geometry of rhombus fins that facilitate distinct fluid flow behavior; nevertheless, the pressure drop is less in the circular fin heat sink. Moreover, for constant value of Re, nanofluid extracts more heat compared to water in both configurations of the heat sink.

Thermal Behaviors of Passively-Cooled Hybrid Fin Heat Sinks for Lightweight and High Performance Thermal Management

2015 ◽  
Author(s):  
Nico Setiawan Effendi ◽  
Kyoung Joon Kim
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
High Performance ◽  
Heat Dissipation ◽  
Computational Study ◽  
Heat Sinks ◽  
Channel Diameter ◽  
Internal Channel ◽  
Study Results ◽  
Parametric Effects

A computational study is conducted to explore thermal performances of natural convection hybrid fin heat sinks (HF HSs). The proposed HF HSs are a hollow hybrid fin heat sink (HHF HS) and a solid hybrid fin heat sink (SHF HS). Parametric effects such as a fin spacing, an internal channel diameter, a heat dissipation on the performance of HF HSs are investigated by CFD analysis. Study results show that the thermal resistance of the HS increases while the mass-multiplied thermal resistance of the HS decreases associated with the increase of the channel diameter. The results also shows the thermal resistance of the SHF HS is 13% smaller, and the mass-multiplied thermal resistance of the HHF HS is 32% smaller compared with the pin fin heat sink (PF HS). These interesting results are mainly due to integrated effects of the mass-reduction, the surface area enhancement, and the heat pumping via the internal channel. Such better performances of HF HSs show the feasibility of alternatives to the conventional PF HS especially for passive cooling of LED lighting modules.

Flow Patterns During Flow Boiling Instability in Silicon-Based Pin-Fin Microchannels

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Fayao Xu ◽  
Huiying Wu ◽  
Zhenyu Liu
Keyword(s):  
Single Phase ◽  
Flow Instability ◽  
Flow Boiling ◽  
Flow Patterns ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Pin Fin ◽  
Short Period ◽  
Pin Fins ◽  
Amplitude Mode

In this paper, the flow patterns during water flow boiling instability in pin-fin microchannels were experimentally studied. Three types of pin-fin arrays (in-line/circular pin-fins, staggered/circular pin-fins, and staggered/square pin-fins) were used in the study. The flow instability started to occur as the outlet water reached the saturation temperature. Before the unstable boiling, a wider range of stable boiling existed in the pin-fin microchannels compared to that in the plain microchannels. Two flow instability modes for the temperature and pressure oscillations, which were long-period/large-amplitude mode and short-period/small-amplitude mode, were identified. The temperature variation during the oscillation period of the long-period/large-amplitude mode can be divided into two stages: increasing stage and decreasing stage. In the increasing stage, bubbly flow, vapor-slug flow, stratified flow, and wispy flow occurred sequentially with time for the in-line pin-fin microchannels; liquid single-phase flow, aforementioned four kinds of two-phase flow patterns, and vapor single-phase flow occurred sequentially with time for the staggered pin-fin microchannel. The flow pattern transitions in the decreasing stage were the inverse of those in the increasing stage for both in-line and staggered pin-fin microchannels. For the short-period/small-amplitude oscillation mode, only the wispy flow occurred. With the increase of heat flux, the wispy flow and the vapor single-phase flow occupied more and more time ratio during an oscillation period in the in-line and staggered pin-fin microchannels.

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