Design of Optimum Plate-Fin Natural Convective Heat Sinks

2003 ◽  
Vol 125 (2) ◽  
pp. 208-216 ◽  
Author(s):  
Avram Bar-Cohen ◽  
Madhusudan Iyengar ◽  
Allan D. Kraus
Keyword(s):  
Nusselt Number ◽  
Specific Heat ◽  
Rectangular Plate ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Thermal Design ◽  
Heat Sinks ◽  
And Performance ◽  
Nusselt Number Correlation ◽  
The Impact

The effort described herein extends the use of least-material single rectangular plate-fin analysis to multiple fin arrays, using a composite Nusselt number correlation. The optimally spaced least-material array was also found to be the globally best thermal design. Comparisons of the thermal capability of these optimum arrays, on the basis of total heat dissipation, heat dissipation per unit mass, and space claim specific heat dissipation, are provided for several potential heat sink materials. The impact of manufacturability constraints on the design and performance of these heat sinks is briefly discussed.

Economic and Performance Evaluation of Heat Sink Options in Combined Cycle Applications

2003 ◽  
Author(s):  
Rattan Tawney ◽  
Zahid Khan ◽  
Justin Zachary
Keyword(s):  
Heat Sink ◽  
Power Plants ◽  
Operation Mode ◽  
Combined Cycle ◽  
Heat Sinks ◽  
Site Location ◽  
Wastewater Disposal ◽  
Environmental Requirements ◽  
And Performance ◽  
The Impact

Because of the current environmental requirements for zero discharge from power plants and scarcity of water, the cooling tower—a proven and industry-recognized conventional option for combined cycle application heat sinks—is being scrutinized by designers, developers, operators, and regulatory agencies. This paper is a guideline to selecting the most appropriate solution for the plant heat sink based on water availability, site location, and wastewater disposal requirements. The paper discusses wet as well as dry cooling systems and evaluates the impact of heat sink selection for cogeneration applications and merchant power plant cycling operation mode. For each proposed option, the performance, relative costs, and noise issues will be presented.

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.

scholarly journals Study of Mini Channel Heat Sink with Different Internal Configuration

2020 ◽  
Vol 319 ◽  
pp. 02004
Author(s):  
Muhammad Akif Rahman ◽  
Md Badrath Tamam ◽  
Md Sadman Faruque ◽  
A.K.M. Monjur Morshed
Keyword(s):  
Nusselt Number ◽  
Thermal Performance ◽  
Heat Sink ◽  
Rectangular Channel ◽  
Three Dimensional ◽  
Heat Sinks ◽  
Maximum Temperature ◽  
Rectangular Channels ◽  
Flow Through ◽  
Internal Configuration

In this paper a numerical analysis of three-dimensional laminar flow through rectangular channel heat sinks of different geometric configuration is presented and a comparison of thermal performance among the heat sinks is discussed. Liquid water was used as coolant in the aluminum made heat sink with a glass cover above it. The aspect ratio (section height to width) of rectangular channels of the mini-channel heat sink was 0.33. A heat flux of 20 W/cm2 was continuously applied at the bottom of the channel with different inlet velocity for Reynold’s number ranging from 150 to 1044. Interconnectors and obstacles at different positions and numbers inside the channel were introduced in order to enhance the thermal performance. These modifications cause secondary flow between the parallel channels and the obstacles disrupt the boundary layer formation of the flow inside the channel which leads to the increase in heat transfer rate. Finally, Nusselt number, overall thermal resistance and maximum temperature of the heat sink were calculated to compare the performances of the modified heat sinks with the conventional mini channel heat sink and it was observed that the heat sink with both interconnectors and obstacles enhanced the thermal performance more significantly than other configurations. A maximum of 36% increase in Nusselt number was observed (for Re =1044).

Compact Modeling of Fluid Flow and Heat Transfer in Straight Fin Heat Sinks

2004 ◽  
Vol 126 (2) ◽  
pp. 247-255 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Heat Sink ◽  
Volume Averaging ◽  
Thermal Design ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Flow And Heat Transfer

In the present work, a compact modeling method based on a volume-averaging technique is presented. Its application to an analysis of fluid flow and heat transfer in straight fin heat sinks is then analyzed. In this study, the straight fin heat sink is modeled as a porous medium through which fluid flows. The volume-averaged momentum and energy equations for developing flow in these heat sinks are obtained using the local volume-averaging method. The permeability and the interstitial heat transfer coefficient required to solve these equations are determined analytically from forced convective flow between infinite parallel plates. To validate the compact model proposed in this paper, three aluminum straight fin heat sinks having a base size of 101.43mm×101.43mm are tested with an inlet velocity ranging from 0.5 m/s to 2 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. The resulting pressure drop across the heat sink and the temperature distribution at its bottom are then measured and are compared with those obtained through the porous medium approach. Upon comparison, the porous medium approach is shown to accurately predict the pressure drop and heat transfer characteristics of straight fin heat sinks. In addition, evidence indicates that the entrance effect should be considered in the thermal design of heat sinks when Re Dh/L>∼O10.

scholarly journals Mathematical modeling and numerical simulation of heat dissipation in led bulbs

2020 ◽  
Vol 24 (3 Part A) ◽  
pp. 1877-1884 ◽  
Author(s):  
Diego Alarcón ◽  
Eduardo. Balvís ◽  
Ricardo Bendaña ◽  
Alberto Conejero ◽  
de Fernández ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Numerical Simulations ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Thermal Contact ◽  
Heat Sinks ◽  
Experimental Measurements ◽  
Heating And Cooling ◽  
The Common

We present a detailed study of heating and cooling processes in LED luminaires with passive heat sinks. Our analysis is supported by numerical simulations as well as experimental measurements, carried on commercial systems used for outdoor lighting. We have focused our analysis on the common case of a single LED source in thermal contact with an aluminum passive heat sink, obtaining an excellent agreement with experimental measurements and the numerical simulations performed. Our results can be easily expanded, without loss of generality, to similar systems.

Bootstrap Statistical Method to Attain the Average Nusselt Number Correlation for Milli Channels and Micro Channels Heat Sink Using Aluminum Oxide (Al2O3)/Water Nanofluid

2008 ◽  
Author(s):  
Guillermo E. Valencia ◽  
Jose D. Aldana ◽  
Miguel A. Ramos ◽  
Antonio J. Bula
Keyword(s):  
Nusselt Number ◽  
Statistical Method ◽  
Heat Sink ◽  
Least Square ◽  
Cooling Fluid ◽  
Micro Channels ◽  
Future Experimentation ◽  
Least Square Approach ◽  
Prandtl Numbers ◽  
Nusselt Number Correlation

The Bootstrap Statistical method is applied for estimating the accuracy of the convective heat transfer non linear correlation of AL2O3 nanofluid working as cooling fluid. The flow experiment considers laminar and turbulent regimen through an array of aluminum microchannels and millichannels heat sink, taking into account the Volume Fractions, Reynolds, Peclet and Prandtl numbers. The β’s parameters are estimated with nonlinear least square approach. StatGraphics® was used, considering the Gauss-Newton algorithm with Levenberg-Marquardt modifications for global convergence. Correlation for Nusselt number is presented and suggestions for future experimentation are presented in order to improve the accuracy of the regression.

Understanding the Impact of Flow Bypass on the Thermal Performance of Air Cooled Heat Sinks

2014 ◽  
Author(s):  
Krishna Kota ◽  
Mohamed M. Awad
Keyword(s):  
Energy Conservation ◽  
Thermal Resistance ◽  
Thermal Performance ◽  
Heat Sink ◽  
Heat Sinks ◽  
Laminar Regime ◽  
Flow Energy ◽  
Factor Α ◽  
The Impact ◽  
Fundamental Mass

In this effort, theoretical modeling was employed to understand the impact of flow bypass on the thermal performance of air cooled heat sinks. Fundamental mass and flow energy conservation equations across a longitudinal fin heat sink configuration and the bypass region were applied and a generic parameter, referred as the Flow Bypass Factor (α), was identified from the theoretical solution that mathematically captures the effect of flow bypass as a quantifiable parameter on the junction-to-ambient thermal resistance of the heat sink. From the results obtained, it was found that, at least in the laminar regime, the impact of flow bypass on performance can be neglected for cases when the bypass gap is typically less than 5% of the fin height, and is almost linear at high relative bypass gaps (i.e., usually for bypass gaps that are more than 10–15% of the fin height). It was also found that the heat sink thermal resistance is more sensitive to small bypass gaps and the effect of flow bypass decreases with increasing bypass gap.

Experimental Investigation of a PCM-Based Topology Optimized Heat Sink for Passive Cooling of Electronics

2020 ◽  
Author(s):  
Jin Yao Ho ◽  
Kai Choong Leong
Keyword(s):  
Thermal Performance ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Heat Fluxes ◽  
Heat Sinks ◽  
Base Temperature ◽  
Storage Unit ◽  
Cooling Of Electronics

Abstract A thermal energy storage unit filled with phase change material (PCM) can serve as a heat sink for the cooling of electronics with intermittent or periodic heat dissipation rates. The use of thermal conductive structures (TCS) is an effective method of improving the thermal performance of a PCM-based heat sink. In this paper, topology optimization is explored to develop a new class of TCS with a tree-like structure to enhance the thermal performance of a trapezoidal heat sink. The topology-optimized heat sink was then fabricated by Selective Laser Melting (SLM) using an aluminum alloy, AlSi10Mg, as the base powder. Experiments were performed to evaluate the thermal performance of the topology-optimized heat sink with the tree-like structure. In addition, a conventional longitudinal-fin heat sink of the same solid volume fraction (φ = 16.2%) and a heat sink without enhanced structure were also fabricated and experimentally investigated for comparison. Rubitherm RT-35HC paraffin wax was used as the PCM. Three different heat fluxes of 4.00 kW/m2, 5.08 kW/m2 and 7.24 kW/m2 were applied at the base of each specimen by a silicone rubber heater. The structure wall and the PCM temperatures were measured over time. Our results show that, for all heat rates tested, the topology-optimized heat sink was able to maintain a lower base temperature as compared to the fin-structure and the plain heat sinks. A thermal enhancement ratio (ε) is defined to evaluate the performance of the heat sinks with and without the use of PCM. From the experimental results, the highest ε value of 8.6 was achieved by the topology-optimized heat sink. These results indicate the better performance of the topology-optimized heat sink in dissipating heat as compared to the other specimens.

Enabling Thermal Management of High-Powered Server Processors Using Passive Thermosiphon Heat Sink

2019 ◽  
Author(s):  
Devdatta P. Kulkarni ◽  
Priyanka Tunuguntla ◽  
Guixiang Tan ◽  
Casey Carte
Keyword(s):  
Heat Pipe ◽  
High Power ◽  
Heat Sink ◽  
Capital Investment ◽  
Thermal Design ◽  
Heat Sinks ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Two Phase ◽  
Pipe Heat

Abstract In recent years, rapid growth is seen in computer and server processors in terms of thermal design power (TDP) envelope. This is mainly due to increase in processor core count, increase in package thermal resistance, challenges in multi-chip integration and maintaining generational performance CAGR. At the same time, several other platform level components such as PCIe cards, graphics cards, SSDs and high power DIMMs are being added in the same chassis which increases the server level power density. To mitigate cooling challenges of high TDP processors, mainly two cooling technologies are deployed: Liquid cooling and advanced air cooling. To deploy liquid cooling technology for servers in data centers, huge initial capital investment is needed. Hence advanced air-cooling thermal solutions are being sought that can be used to cool higher TDP processors as well as high power non-CPU components using same server level airflow boundary conditions. Current air-cooling solutions like heat pipe heat sinks, vapor chamber heat sinks are limited by the heat transfer area, heat carrying capacity and would need significantly more area to cool higher TDP than they could handle. Passive two-phase thermosiphon (gravity dependent) heat sinks may provide intermediate level cooling between traditional air-cooled heat pipe heat sinks and liquid cooling with higher reliability, lower weight and lower cost of maintenance. This paper illustrates the experimental results of a 2U thermosiphon heat sink used in Intel reference 2U, 2 node system and compare thermal performance using traditional heat sinks solutions. The objective of this study was to showcase the increased cooling capability of the CPU by at least 20% over traditional heat sinks while maintaining cooling capability of high-power non-CPU components such as Intel’s DIMMs. This paper will also describe the methodology that will be used for DIMMs serviceability without removing CPU thermal solution, which is critical requirement from data center use perspective.

scholarly journals Towards a Thermal Moore’s Law

2005 ◽  
Author(s):  
Shankar Krishnan ◽  
Suresh V. Garimella ◽  
Greg M. Chrysler ◽  
Ravi V. Mahajan
Keyword(s):  
Heat Sink ◽  
High Efficiency ◽  
Thermal Design ◽  
Air Cooling ◽  
Thermoelectric Coolers ◽  
Moore’S Law ◽  
Moore's Law ◽  
The Impact ◽  
Power Densities ◽  
Design Power

The thermal design power trends and power densities for present and future microprocessors are investigated. The trends are derived based on Moore’s law and scaling theory. Both active and stand-by power are discussed and accounted for in the calculations. A brief discussion of various leakage power components and their impact on the power density trends is provided. Two different lower limits of heat dissipation for irreversible logic computers are discussed. These are based on the irreversibility of logic to represent one bit of information, and on the distribution of electrons to represent a bit. These limits are found to be two or more orders of magnitude lower than present-day microprocessor thermal design power trends. Further, these trends are compared to the projected trends for the desktop product sector from the International Technology Roadmap for Semiconductors (ITRS). To evaluate the thermal impact of the projected power densities, heat sink thermal resistances are calculated for a given technology target. Based on the heat sink thermal resistance trends, the evolution of an air-cooling limit consistent with Moore’s law is predicted. One viable alternative to air-cooling, i.e., the use of high-efficiency solid-state thermoelectric coolers (TECs), is explored. The impact of different parasitics on the thermoelectric figure of merit (ZT) is quantified.   This paper was also originally published as part of the Proceedings of the ASME 2005 Heat Transfer Summer Conference.

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