Thermal Spreading Analysis of Rectangular Heat Spreader

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
S. M. Thompson ◽  
H. B. Ma
Keyword(s):  
Expansion Method ◽  
Area Ratio ◽  
Maximum Temperature ◽  
Heat Spreader ◽  
Two Phase ◽  
Cosine Series ◽  
Steady State Temperature ◽  
Heat Spreaders ◽  
Unique Method ◽  
Biot Numbers

A unique nondimensional scheme that employs a source-to-substrate “area ratio” (e.g., footprint), has been utilized for analytically determining the steady-state temperature field within a centrally-heated, cuboidal heat spreader with square cross-section. A modified Laplace equation was solved using a Fourier expansion method providing for an infinite cosine series solution. This solution can be used to analyze the effects of Biot number, heat spreader thickness, and area ratio on the heat spreader's nondimensional maximum temperature and nondimensional thermal spreading resistance. The solution is accurate only for low Biot numbers (Bi < 0.001); representative of highly-conductive, two-phase heat spreaders. Based on the solution, a unique method for estimating the effective thermal conductivity of a two-phase heat spreader is also presented.

Effect of Area Ratio on Thermal Spreading Resistance of a Cubic Heat Spreader

2013 ◽  
Author(s):  
Scott M. Thompson ◽  
Hongbin Ma
Keyword(s):  
Biot Number ◽  
Area Ratio ◽  
Cross Sectional Area ◽  
Maximum Temperature ◽  
Sectional Area ◽  
Heat Spreader ◽  
Cross Sectional ◽  
Spreading Resistance ◽  
Heat Spreaders ◽  
Biot Numbers

A unique non-dimensional scheme has been employed to analytically determine the steady-state temperature field within a cubic heat spreader of unity aspect-ratio undergoing centralized, uniform heat flux with square footprint. This ‘square-on-square’ boundary value problem was solved using method of Fourier expansion. Plots of the heat spreader non-dimensional maximum temperature and non-dimensional thermal spreading resistance are provided for various Biot numbers, heat spreader thicknesses and a newly-defined ‘area ratio’ — the ratio of heater cross-sectional area to heat spreader cross-sectional area (i.e. footprint). The proposed solution is advantageous for determining optimal heat spreading configurations with low Biot numbers — typical of many electronics packaging applications and heat spreaders of very high effective thermal conductivity. The presented results indicate that the non-dimensional, maximum temperature increases as the area ratio decreases and that a limiting, non-dimensional thermal spreading resistance exists for relatively thick heat spreaders regardless of area ratio or Biot number. A critical, non-dimensional thickness was also found in which the non-dimensional, maximum temperature becomes near unity regardless of Biot number or area ratio.

Design of Micro Heat Spreaders for Electronic Cooling

2004 ◽  
Author(s):  
P. Chiarot ◽  
P. Sullivan ◽  
R. Ben Mrad
Keyword(s):  
Electronic Cooling ◽  
Operating Conditions ◽  
Silicon On Insulator ◽  
Maximum Temperature ◽  
Heat Spreader ◽  
Element Analysis ◽  
Heat Spreaders ◽  
Number Curve ◽  
The Given ◽  
Membrane Deflection

This work presents an active Micro Heat Spreader (MHS) for use in electronic cooling. The device includes four reservoir chambers and is actuated using membrane deflection. An investigation is performed using Finite Element Analysis to determine the performance characteristics of the MHS. Two operating conditions for the actuation order of the membranes are considered. Dimensional similitude is used to obtain a single maximum temperature versus Reynolds number curve for the device at the given operating condition and Prandtl number. Fabrication of the MHS is proposed using the Silicon-on-Insulator (SOI) technique and actuation of the membranes can be achieved using thin film PZT.

scholarly journals Numerical Analysis of Single-Particle Motion Using CFD-DEM in Varying-Curvature Elbows

2022 ◽  
Vol 10 (1) ◽  
pp. 62
Author(s):  
Chao Ning ◽  
Yalin Li ◽  
Ping Huang ◽  
Hongbo Shi ◽  
Haichao Sun
Keyword(s):  
Single Particle ◽  
Particle Motion ◽  
Numerical Study ◽  
Area Ratio ◽  
Centrifugal Pumps ◽  
Distribution Law ◽  
Two Phase ◽  
Curvature Ratio ◽  
Critical Components ◽  
Solid Liquid

Centrifugal pumps are the critical components in deep-sea mining. In order to investigate the particle motion in the curved channel of the impeller, three different types of curvature conform to blade profile to simplify the impeller design of pumps. A numerical study is conducted to investigate the flow field in a varying-curvature channel for solid-liquid two-phase flow. The flow of particles within the varying curvature channel is studied by combining the discrete element method (DEM) with computational fluid dynamics (CFD) and a comparison with Particle Image Velocimetry (PIV) test results. The results show that a polyhedral mesh with a small mesh number yields very accurate results, which makes it very suitable for CFD-DEM. Based on this method, the movement of a single particle is compared and analyzed, and the particle-motion law is obtained. The effects of the curvature ratio Cr and area ratio Ar on the motion law for a single particle are studied, and the simulation results are analyzed statistically. The results show that the effect of Cr on both the particle slip velocity and the turbulent kinetic energy only changes its strength, while the distribution law does not change significantly. Compared with the curvature ratio Cr, the area ratio Ar has a greater impact on the particles, and its distribution law becomes clearly different. As the area ratio Ar increases, the arc radius and length of the corresponding particle trajectory decrease.

scholarly journals Thermal Performance of a Cylindrical Lithium-Ion Battery Module Cooled by Two-Phase Refrigerant Circulation

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8094
Author(s):  
Bichao Lin ◽  
Jiwen Cen ◽  
Fangming Jiang
Keyword(s):  
Thermal Management ◽  
Management System ◽  
Cooling System ◽  
Maximum Temperature ◽  
Two Phase ◽  
Battery Thermal Management ◽  
Thermal Management System ◽  
Battery Thermal Management System ◽  
Li Ion ◽  
Battery Module

It is important for the safety and good performance of a Li-ion battery module/pack to have an efficient thermal management system. In this paper, a battery thermal management system with a two-phase refrigerant circulated by a pump was developed. A battery module consisting of 240 18650-type Li-ion batteries was fabricated based on a finned-tube heat-exchanger structure. This structural design offers the potential to reduce the weight of the battery thermal management system. The cooling performance of the battery module was experimentally studied under different charge/discharge C-rates and with different refrigerant circulation pump operation frequencies. The results demonstrated the effectiveness of the cooling system. It was found that the refrigerant-based battery thermal management system could maintain the battery module maximum temperature under 38 °C and the temperature non-uniformity within 2.5 °C for the various operation conditions considered. The experimental results with 0.5 C charging and a US06 drive cycle showed that the thermal management system could reduce the maximum temperature difference in the battery module from an initial value of 4.5 °C to 2.6 °C, and from the initial 1.3 °C to 1.1 °C, respectively. In addition, the variable pump frequency mode was found to be effective at controlling the battery module, functioning at a desirable constant temperature and at the same time minimizing the pump work consumption.

Design and Optimization of a Composite Heat Spreader to Improve the Thermal Management of a 3D Integrated Circuit

2021 ◽  
Author(s):  
Andisheh Tavakoli ◽  
Kambiz Vafai
Keyword(s):  
Thermal Conductivity ◽  
Heat Sink ◽  
Variable Temperature ◽  
Heat Removal ◽  
High Conductivity ◽  
High Thermal Conductivity ◽  
Maximum Temperature ◽  
Optimal Distribution ◽  
Heat Spreader ◽  
The Impact

Abstract The present study analyzes the optimal distribution of a limited amount of high thermal conductivity material to enhance the heat removal of circular 3D integrated circuits, IC. The structure of the heat spreader is designed as a composite of high thermal conductivity (Boron Arsenide) and moderate thermal conductivity (copper) materials. The volume ratio of high-conductivity inserts to the total volume of the spreader is set at a fixed pertinent ratio. Two different boundary conditions of constant and variable temperature are considered for the heat sink. To examine the impact of adding high-conductivity inserts on the cooling performance of the heat spreader, various patterns of the single and double ring inserts are studied. A parametric study is performed to find the optimal location of the rings. Moreover, the optimal distribution of the high-conductivity material between the inner and outer rings is found. The results show that for the optimal conditions, the maximum temperature of the 3D IC is reduced up to 10%; while the size of the heat sink, and heat spreader can be diminished by as much as 200%.

Efficient Thermal Analysis of Lab-Grown Diamond Heat Spreaders

2021 ◽  
Author(s):  
Zihao Yuan ◽  
Tao Zhang ◽  
Jeroen Van Duren ◽  
Ayse K. Coskun
Keyword(s):  
Steady State ◽  
Real World ◽  
High Performance ◽  
Silicon Layer ◽  
Maximum Temperature ◽  
Cooling Performance ◽  
Thermal Models ◽  
Heat Spreaders ◽  
Transient Simulations ◽  
Transient Thermal

Abstract Lab-grown diamond heat spreaders are becoming attractive solutions compared to traditional copper heat spreaders due to their high thermal conductivity, the ability to directly bond them on silicon, and allow for an ultra-thin silicon layer. Researchers have developed various thermal models and prototypes of lab-grown diamond heat spreaders to evaluate their cooling performance and heat spreading ability. The majority of existing thermal models are built using finite-element method (FEM) based simulators such as COMSOL and ANSYS. However, such commercial simulators are computationally expensive and lead to long solution times along with large memory requirements. These limitations make commercial simulators unsuitable for evaluating numerous design alternatives or runtime scenarios for real-world high-performance processors. Because of this modeling challenge, none of the existing works have evaluated the thermal behavior of lab-grown diamond heat spreaders on real-world high-performance processors running realistic application benchmarks. Recently, we have developed a parallel compact thermal simulator, PACT, that is able to carry out fast and accurate steady-state and transient thermal simulations and can be extended to support emerging integration and cooling technologies. In this paper, we use PACT to evaluate the steady-state and transient cooling performance of lab-grown diamond heat spreaders against traditional copper heat spreaders on various real-world high-performance processors (e.g., Intel i7 6950X, IBM Power9, and PicoSoC). By using PACT with architectural performance and power simulators such as Sniper and McPAT, we are able to run transient simulations with realistic benchmarks. Simulation results show that lab-grown diamond heat spreaders achieve maximum temperature and thermal gradient reductions of up to 26.73 °C and 13.75 °C when compared to traditional copper heat spreaders, respectively. The maximum steady-state and transient simulation times of PACT for the real-world high-performance chips and realistic applications used in our experiments are 259 s and 22 min, respectively.

Integration of Silver Heat Spreaders in LTCC utilizing Thick Silver Tape in the Co-fire Process

2015 ◽  
Vol 2015 (CICMT) ◽  
pp. 000062-000066 ◽  
Author(s):  
T. Welker ◽  
S. Günschmann ◽  
N. Gutzeit ◽  
J. Müller
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Heat Sink ◽  
Junction Temperature ◽  
Large Area ◽  
Heat Spreader ◽  
Integration Density ◽  
Heat Spreaders ◽  
Cte Mismatch ◽  
Pattern Resolution

The integration density in semiconductor devices is significantly increased in the last years. This trend is already described by Moore's law what forecasts a doubling of the integration density every two years. This evolution makes greater demands on the substrate technology which is used for the first level interconnect between the semiconductor and the device package. Higher pattern resolution is required to connect more functions on a smaller chip. Also the thermal performance of the substrate is a crucial issue. The increased integration density leads to an increased power density, what means that more heat has to dissipate on a smaller area. Thus, substrates with a high thermal conductivity (e. g. direct bonded copper (DBC)) are utilized which spread the heat over a large area. However, the reduced pattern resolution caused by thick metal layers is disadvantageous for this substrate technology. Alternatively, low temperature co-fired ceramic (LTCC) can be used. This multilayer technology provides a high pattern resolution in combination with a high integration grade. The poor thermal conductivity of LTCC (3 … 5 W*m−1*K−1) requires thermal vias made of silver paste which are placed between the power chip and the heat sink and reduce the thermal resistance of the substrate. The via-pitch and diameter is limited by the LTCC technology, what allows a maximum filling grade of approx. 20 to 25 %. Alternatively, an opening in the ceramic is created, to bond the chip directly to the heat sink. This leads to technological challenges like the CTE mismatch between the chip and the heat sink material. Expensive materials like copper molybdenum composites with matched CTE have to be used. In the presented investigation, a thick silver tape is used to form a thick silver heat spreader through the LTCC substrate. An opening is structured by laser cutting in the LTCC tape and filled with a laser cut silver tape. After lamination, the substrate is fired using a constraint sintering process. The bond strength of the silver to LTCC interface is approx. 5.6 MPa. The thermal resistance of the silver structure is measured by a thermal test chip (Delphi PST1, 2.5 mm × 2.5 mm) glued with a high thermal conducting epoxy to the silver structure. The chip contains a resistor and diodes to generate heat and to determine the junction temperature respectively. The backside of the test structure is temperature stabilized by a temperature controlled heat sink. The resulting thermal resistance is in the range of 1.1 K/W to 1.5 K/W depending on the length of silver structure (5 mm to 7 mm). Advantages of the presented heat spreader are the low thermal resistance and the good embedding capability in the co-fire LTCC process.

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