Performance Analysis of an Ultrahigh Performance, 3-D Micro Convective Heat Sink With a Nearly Fractal Plumbing System

Volume 4 ◽  
2004 ◽  
Author(s):  
R. Moreno ◽  
Y.-X. Tao
Keyword(s):  
Convective Heat ◽  
Heat Sink ◽  
High Performance ◽  
Silver Film ◽  
High Surface ◽  
Tape Casting ◽  
Volume Ratio ◽  
Pumping Power ◽  
Flow And Heat Transfer ◽  
Point To Point

This paper presents the design and CFD analysis of a 3-D, active micro convective heat sink having high surface-to-volume ratio geometry. The heat sink consists of an array of elemental units arranged in parallel. Each unit is constructed as a network of nearly fractal geometry. The design of each unit uses the constructal method to minimize the point-to-point temperature difference within the heat sink and Murray’s Law to minimize pressure drop across the device. The heat sink is designed for the tape casting fabrication method using thick silver film techniques and co–fired with low temperature co-fired ceramic substrate. To analyze fluid flow and heat transfer characteristics of the design, we use the Fluent CFD software. The numerical results are presented to validate the theoretical optimization and outline the ultra-high performance characteristics of the heat sink such as the overall thermal resistance, pumping power and effectiveness.

Experimental Study of an Ultra-High Performance, 3-D Micro Convective Heat Sink With a Constructal Plumbing System

2004 ◽  
Author(s):  
R. Moreno ◽  
Y.-X. Tao
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Convective Heat ◽  
Heat Sink ◽  
High Performance ◽  
Theoretical Calculations ◽  
High Surface ◽  
Tape Casting ◽  
Volume Ratio ◽  
Point To Point

This paper presents the fabrication and results of an experimental study carried out to determine the thermal fluid performance of a 3-D, active micro convective heat sink having high surface-to-volume ratio geometry. The heat sink consists of an array of elemental units arranged in parallel. Each unit is constructed as a network of nearly fractal geometry. The design of each unit uses the constructal method to minimize the point-to-point temperature difference within the heat sink and Murray’s Law to minimize pressure drop across the device. One elemental unit of the heat sink was manufactured using the tape casting fabrication method with thick silver film techniques. An experiment was conducted using water as the coolant under laminar flow conditions to obtain the pressure drop and heat transfer characteristics of the 3-D micro convective heat sink. The results were then compared with theoretical calculations.

Design Analysis of a 3-D, Ultra-High Performance, Scalable, Micro Convective Heat Sink With NPCM

2003 ◽  
Author(s):  
Y.-X. Tao ◽  
R. Moreno ◽  
Y. Hao
Keyword(s):  
Phase Change ◽  
Heat Sink ◽  
High Performance ◽  
Phase Change Materials ◽  
High Surface ◽  
Volume Ratio ◽  
Cooling Capacity ◽  
System Level ◽  
Uniform Heat Flux ◽  
Order Of Magnitude

The paper proposes a new design of a scalable, heat sink containing 3-D micro/nano network, utilizing liquid mixed with nano phase change materials (NPCM) and having a high surface-to-volume ratio geometry. The conceptual design is capable of reaching 105 W/cm3 using encapsulated nano-size phase change materials, which would result in an order of magnitude higher cooling capacity than typical microchannel heat sink of the same volume and same pumping power. It is also scalable to submicron range, resulting even higher cooling capacity. An analysis for a working model (10 × 10 × 1 mm) is presented utilizing energy conservation principle and uniform temperature and uniform heat flux boundary conditions. The average phase change heat transfer coefficient is obtained using the numerical model results. A process of micro electrochemical deposition to fabricate the target model is illustrated, and the issues associated with system-level applications are discussed.

Thermal Optimization of Microchannel Heat Sink With Pin Fin Structures

2003 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Heat Sink ◽  
Volume Averaging ◽  
Heat Sinks ◽  
Pumping Power ◽  
Heat Transfer Characteristics ◽  
Pin Fin ◽  
Flow And Heat Transfer

In the present work, a novel compact modeling method based on the volume-averaging technique and its application to the analysis of fluid flow and heat transfer in pin fin heat sinks are presented. The pin fin heat sink is modeled as a porous medium. The volume-averaged momentum and energy equations for fluid flow and heat transfer in pin fin heat sinks are obtained using the local volume-averaging method. The permeability, the Ergun constant and the interstitial heat transfer coefficient required to solve these equations are determined experimentally. To validate the compact model proposed in this paper, 20 aluminum pin fin heat sinks having a 101.43 mm × 101.43 mm base size are tested with an inlet velocity ranging from 1 m/s to 5 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. Pressure drop and heat transfer characteristics of pin fin heat sinks obtained from the porous medium approach are compared with experimental results. Upon comparison, the porous medium approach is shown to predict accurately the pressure drop and heat transfer characteristics of pin fin heat sinks. Finally, surface porosities of the pin fin heat sink for which the thermal resistance of the heat sink is minimal are obtained under constraints on pumping power and heat sink size. The optimized pin fin heat sinks are shown to be superior to the optimized straight fin heat sinks in thermal performance by about 50% under the same constraints on pumping power and heat sink size.

A Comparative Numerical Study on Two-Phase Boiling Fluid Flow and Heat Transfer in the Microchannel Heat Sink With Different Manifold Arrangements

2020 ◽  
Author(s):  
Yang Luo ◽  
Jingzhi Zhang ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Sink ◽  
Numerical Study ◽  
Flow Boiling ◽  
High Surface ◽  
Volume Ratio ◽  
High Heat Flux ◽  
Two Phase ◽  
Flow Maldistribution

Abstract The manifold microchannel (MMC) heat sink system has been widely used in high-heat-flux chip thermal management due to its high surface-to-volume ratio. Two-phase, three-dimensional numerical methods for subcooled flow boiling have been developed using a self-programming solver based on OpenFOAM. Four different types of manifold arrangements (Z-type, C-type, H-type and U-type) have been investigated at a fixed operational condition. The numerical results evaluate the effects of flow maldistribution caused by different manifold configurations. Before simulating the two-phase boiling flow in MIMC metamodels, single-phase liquid flow fields are performed at first to compare the flow maldistribution in microchannels. It can be concluded from the flow patterns that H-type and U-type manifolds provide a more even and a lower microchannel void fraction, which is conducive to improving the temperature uniformity and decreasing the effective thermal resistance. The simulation results also show that the wall temperature difference of H-type (0.471 K) is only about 10% of the Z-type (4.683 K). In addition, the U-type manifold configuration show the lowest average pressure drop at the inlet and outlet of the MIMC metamodel domain. However, H-type manifold also shows an impressive 59.9% decrease in pressure loss. Results indicate that both the H-type and the U-type manifolds for flow boiling in microchannels are recommended due to their better heat transfer performance and lower pressure drop when compared with Z-type and C-type.

Semimetallic vanadium molybdenum sulfide for high-performance battery electrodes

2018 ◽  
Vol 6 (20) ◽  
pp. 9411-9419 ◽  
Author(s):  
Qingfeng Zhang ◽  
Longlu Wang ◽  
Jue Wang ◽  
Xinzhi Yu ◽  
Junmin Ge ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Electrode Material ◽  
High Performance ◽  
High Surface ◽  
Volume Ratio ◽  
Lithium Ion ◽  
Diffusion Path ◽  
Molybdenum Sulfide ◽  
Two Dimensional

The ultrathin thickness and lateral morphology of a two dimensional (2D) MoS2 nanosheet contribute to its high surface-to-volume ratio and short diffusion path, rendering it a brilliant electrode material for lithium-ion batteries (LIBs).

One-dimensional inorganic semiconductor nanostructures: A new carrier for nanosensors

2010 ◽  
Vol 82 (11) ◽  
pp. 2185-2198 ◽  
Author(s):  
Xiaosheng Fang ◽  
Linfeng Hu ◽  
Changhui Ye ◽  
Lide Zhang
Keyword(s):  
High Performance ◽  
High Surface ◽  
Volume Ratio ◽  
Semiconductor Nanostructures ◽  
One Dimensional ◽  
Semiconductor Nanostructure ◽  
Research Activities ◽  
Wide Range ◽  
Inorganic Semiconductor ◽  
Art Research

One-dimensional (1D) inorganic semiconductor nanostructures have witnessed an explosion of interest over the last decade because of advances in their controlled synthesis and unique property and potential applications. A wide range of gases, chemicals, biomedical nanosensors, and photodetectors have been assembled using 1D inorganic semiconductor nanostructures. The high-performance characteristics of these nanosensors are particularly attributable to the inorganic semiconducting nanostructure high surface-to-volume ratio (SVR) and its rationally designed surface. In this review, we provide a brief summary of the state-of-the-art research activities in the field of 1D inorganic semiconductor nanostructure-based nanosensors. Some perspectives and the outlook for future developments in this area are presented.

Nonenzymatic Alkaline Direct Glucose Fuel Cell With a Silicon Microchannel Plate Supported Electrocatalytic Electrode

2013 ◽  
Vol 10 (4) ◽  
Author(s):  
Fengjuan Miao ◽  
Bairui Tao ◽  
JunHao Chu
Keyword(s):  
Fuel Cell ◽  
High Performance ◽  
Energy Dispersive Spectrometer ◽  
High Surface ◽  
Electrochemical Techniques ◽  
Volume Ratio ◽  
Reduction Reaction ◽  
Microchannel Plate ◽  
Highly Active ◽  
Direct Glucose Fuel Cell

Highly active Pd-Ni/Si microchannel plate (MCP) electrocatalytic electrode has been synthesized by combining conventional microelectronics technology with electrochemical techniques. The obtained Pd-Ni/Si-MCP electrocatalytic electrode was characterized by SEM, energy dispersive spectrometer (EDS), XRD, and electrochemical measurements. The results show that Pd-Ni/Si-MCP electrocatalytic electrode possesses better stability and higher activity in comparison with Pd-Ni/Si prepared by the same procedure. The high performance of the fuel cell is mainly attributed to the increased kinetics of both the glucose oxidation reaction and oxygen reduction reaction, rendered by a better electrocatalytic activity of Pd-Ni nanoparticles, ordered microchannels, and high surface-to-volume ratio of backbone Si-MCP. Especially, the compatibility of silicon microelectronics processing could achieve monolithic integration of Si-based microfabricated fuel cells.

Fabrication of high performance amine-rich magnetic composite fibers for the recovery of precious Pt(iv) from acidic solutions

RSC Advances ◽  
2016 ◽  
Vol 6 (92) ◽  
pp. 89089-89097 ◽  
Author(s):  
Myung-Hee Song ◽  
D. Harikishore Kumar Reddy ◽  
Yeoung-Sang Yun
Keyword(s):  
Magnetic Nanoparticles ◽  
Water Treatment ◽  
Aqueous Solutions ◽  
Active Sites ◽  
High Performance ◽  
High Surface ◽  
Volume Ratio ◽  
Magnetic Composite ◽  
Composite Fibers ◽  
Acidic Solutions

Magnetic nanoparticles (MNPs) possessing a high surface to volume ratio, copious chemically active sites, and ease of separation from aqueous solutions are emerging materials for water treatment.

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

2004 ◽  
Vol 126 (3) ◽  
pp. 342-350 ◽  
Author(s):  
Duckjong Kim ◽  
Sung Jin Kim ◽  
Alfonso Ortega
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Fluid Flow ◽  
Heat Sink ◽  
Volume Averaging ◽  
Heat Sinks ◽  
Compact Modeling ◽  
Pumping Power ◽  
Pin Fin ◽  
Flow And Heat Transfer

In this work, a novel compact modeling method based on the volume-averaging technique is presented. Its application to the analysis of fluid flow and heat transfer in pin fin heat sinks are further analyzed. The pin fin heat sink is modeled as a porous medium. The volume-averaged momentum and energy equations for fluid flow and heat transfer in pin fin heat sinks are obtained by using the local volume-averaging method. The permeability, the Ergun constant, and the interstitial heat transfer coefficient required to solve these equations are determined experimentally and correlations for them are presented. To validate the compact model proposed in this paper, 20 aluminum pin fin heat sinks having a 101.43 mm×101.43 mm base size are tested with an inlet velocity ranging from 1 m/s to 5 m/s. In the experimental investigation, the heat sink is heated uniformly at the bottom. Pressure drop and heat transfer characteristics of pin fin heat sinks obtained from the porous medium approach are compared with experimental results. Upon comparison, the porous medium approach is shown to predict accurately the pressure drop and heat transfer characteristics of pin fin heat sinks. Finally, for minimal thermal resistance, the optimum surface porosities of the pin fin heat sink are obtained under constraints on pumping power and heat sink size. The optimized pin fin heat sinks are shown to be superior to the optimized straight fin heat sinks in thermal performance by about 50% under the same constraints on pumping power and heat sink size.

Pd-Decorated Multi-Walled Carbon Nanotube Sensor for Hydrogen Detection

2021 ◽  
Vol 21 (7) ◽  
pp. 3707-3710
Author(s):  
Jae Keon Kim ◽  
Maeum Han ◽  
Yeongsam Kim ◽  
Hee Kyung An ◽  
Suwoong Lee ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Gas Sensors ◽  
High Performance ◽  
Room Temperature ◽  
Catalytic Effect ◽  
High Surface ◽  
Volume Ratio ◽  
Ambient Atmosphere ◽  
Low Concentrations ◽  
Multi Walled Carbon Nanotube

As hydrogen (H2) gas is highly reactive and explosive in ambient atmosphere, its prompt detection in industrial areas is imperative to prevent serious accidents. In particular, high-performance H2 sensors that can promptly detect even low-concentrations of H2 gas are necessary for safety. Carbon nanotubes (CNTs) have a large surface area and a high surface-to-volume ratio, and therefore, they are suitable for use as sensing materials in gas sensors. Moreover, gold, platinum, and palladium are known to be excellent catalyst metals that increase reactivity with H2 gas through the catalytic effect referred to as spill-over mechanism. In this study, a CNT felt sensor with a palladium (Pd) layer was fabricated, and its reactivity with H2 was evaluated. The sensitivity of a CNT felt sensor to H2 gas at room temperature was found to improve when coated with Pd layer.

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