A Numerical Study of Single Phase Dielectric Fluid Immersion Cooling of Multichip Modules

2012 ◽  
Vol 2012 (1) ◽  
pp. 000581-000590
Author(s):  
Roy W. Knight ◽  
Seth Fincher ◽  
Sushil H. Bhavnani ◽  
Daniel K. Harris ◽  
R. Wayne Johnson
Keyword(s):  
Single Phase ◽  
Printed Circuit Board ◽  
Numerical Study ◽  
Design Guidelines ◽  
Circuit Board ◽  
Dielectric Fluid ◽  
Multichip Modules ◽  
Ansys Fluent ◽  
Immersion Cooling ◽  
Numerical Parametric Study

Immersion, single phase free convection cooling of multichip modules on a printed circuit board in a pool of dielectric fluid was examined numerically, with experimental verification of baseline cases. A multi-chip module with multiple thermal test cells with temperature sensing capability was simulated. The commercially available computational fluid dynamics program from ANSYS, Fluent, was used with the electronics packaging front end, Icepak, employed to create the models and compact conduction modules. Simulations were first performed of an experimental test vehicle which had five 18 mm by 18 mm die, arranged in a cross pattern, equally spaced die, 25 mm between them. Two of the die were aligned vertically with the center die, two aligned horizontally with it. The board was suspended vertically in a large pool of dielectric fluid. Heat was dissipated in the die at a flux of up to 2 W/cm2, based on the die surface area. Simulation results were compared with experimentally measured die temperature values and excellent agreement was seen for the cases of one die heated and all five die uniformly heated with the board cooled by FC-72. A numerical parametric study was performed to examine the effect of die size and spacing on temperature rise. In addition to FC-72, immersion cooling in Novec 649 and HFE 7100 were modeled. Design guidelines are suggested for dielectric fluid immersion cooled multichip modules.

Evaluating the Reliability of Passive Server Components for Single-Phase Immersion Cooling

2021 ◽  
Author(s):  
Jimil M. Shah ◽  
Keerthivasan Padmanaban ◽  
Hrishabh Singh ◽  
Surya Duraisamy Asokan ◽  
Satyam Saini ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Single Phase ◽  
Printed Circuit Board ◽  
Structural Integrity ◽  
Circuit Board ◽  
Dielectric Fluid ◽  
Air Cooling ◽  
Passive Components ◽  
Material Compatibility ◽  
Immersion Cooling

Abstract The adoption of Single-phase Liquid Immersion Cooling (Sp-LIC) for Information Technology equipment provides an excellent cooling platform coupled with significant energy savings. There are, however, very limited studies related to the reliability of such cooling technology. The Accelerated Thermal Cycling (ATC) test given ATC JEDEC is relevant just for air cooling but there is no such standard for immersion cooling. The ASTM benchmark D3455 with some appropriate adjustments was adopted to test the material compatibility because of the air and dielectric fluid differences in the heat capacitance property and corresponding ramp rate during thermal cycling. For this study, accelerated thermal degradation of the printed circuit board (PCB), passive components, and fiber optic cables submerged in air, white mineral oil, and synthetic fluid at a hoisted temperature of 45C and 35% humidity is undertaken. This paper serves multiple purposes including designing experiments, testing and evaluating material compatibility of PCB, passive components, and optical fibers in different hydrocarbon oils for single-phase immersion cooling. Samples of different materials were immersed in different hydrocarbon oils and air and kept in an environmental chamber at 45C for a total of 288 hours. Samples were then evaluated for their mechanical and electrical properties using Dynamic Mechanical Analyzer (DMA) and a multimeter, respectively. The cross-sections of some samples were also investigated for their structural integrity using SEM. The literature gathered on the subject and quantifiable data gathered by the authors provide the primary basis for this research document.

scholarly journals Numerical Study on the Tandem Submerged Hydrofoils Using RANS Solver

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Moloud Arian Maram ◽  
Hamid Reza Ghafari ◽  
Hassan Ghassemi ◽  
Mahmoud Ghiasi
Keyword(s):  
Drag Coefficient ◽  
Single Phase ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Lower Surface ◽  
Phase Flow ◽  
Two Phase ◽  
Hydrodynamic Coefficient ◽  
Ansys Fluent

This paper is presented on the tandem two-dimensional hydrofoils with profiles NACA4412 in single-phase and two-phase flow domains for different submergence depths and different distances in a various angle of attack (AoA). Also, supercavitation is studied at σ = 0.34 by the Zwart cavitation model. Reynolds-averaged Navier–Stokes (RANS) with the shear stress transport (SST) K-ω is employed as a turbulence model in transient analysis of Ansys FLUENT software. The numerical results show that, by increasing depth, the drag coefficient increases for both hydrofoils 1 and 2 as well as the lift coefficient. The drag coefficient of hydrofoil 2 is bigger than hydrofoil 1 for all depths; moreover, it was found that the flow pressure behind the hydrofoil 1 had affected the upper and the lower surface of the hydrofoil 2 at each distance or AoA. These effects are observed in the hydrofoil 2 lift coefficient as well as the flow separation. However, the maximum lift-to-drag ratio is observed at AoA =  8 ° and 3.5c distance. Also, single-phase results reveal that the value of pressure and the hydrodynamic coefficient are very different from the two-phase flow results, due to the elimination of the free surface. So, a two-phase flow domain is recommended for increasing the accuracy of results. In addition, the investigation of supercavitation shows a growth in cavity occurrence on the surface by raising AoA.

Numerical simulation of the single-phase immersion cooling process using a dielectric fluid in a data server

2021 ◽  
Author(s):  
Aditya Chhetri ◽  
Devendra Kashyap ◽  
Arvind Mali ◽  
Chaitanya Agarwal ◽  
Caroline Ponraj ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Single Phase ◽  
Dielectric Fluid ◽  
Cooling Process ◽  
Immersion Cooling

Numerical Analysis of Buoyancy-Induced Flow and Heat Transfer in an Enclosure With Vents

2000 ◽  
Author(s):  
V. V. Calmidi ◽  
S. B. Sathe
Keyword(s):  
Heat Transfer ◽  
Printed Circuit Board ◽  
Numerical Study ◽  
Electronics Cooling ◽  
Circuit Board ◽  
Set Top Box ◽  
Flow And Heat Transfer ◽  
Quantitative Results ◽  
Induced Flow ◽  
Buoyancy Induced Flow

Abstract This paper reports a numerical study of buoyancy-induced flow and heat transfer in an enclosure with vents. The geometry closely resembles a “set-top-box” application frequently encountered in electronics cooling applications. The heat generating module is modeled as a planar heat source placed on a conducting printed circuit board (PCB). Full 3D and simplified 2D conjugate heat transfer models accounting for conduction and radiation in the solids and conduction and convection in the fluid were used Experiments performed to validate the 3D model have shown excellent comparisons with numerical results. A parametric study involving vent size, power dissipation, number of high conductivity power planes in the PCB has been performed with both the 3D and the 2D models. Although the quantitative results obtained from both types of analyses are similar only under certain conditions, qualitatively, the 2D analysis can be used to obtain useful insights into the complex overall transport mechanisms.

Computational Analysis for Thermal Optimization of Server for Single Phase Immersion Cooling

2019 ◽  
Author(s):  
Dhruvkumar Gandhi ◽  
Uschas Chowdhury ◽  
Tushar Chauhan ◽  
Pratik Bansode ◽  
Satyam Saini ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Single Phase ◽  
Data Centers ◽  
Dielectric Fluid ◽  
Air Cooling ◽  
Processing Unit ◽  
Input Output ◽  
Dielectric Fluids ◽  
Immersion Cooling ◽  
Oil Immersion

Abstract Complete immersion of servers in synthetic dielectric fluids is rapidly becoming a popular technique to minimize the energy consumed by data centers for cooling purposes. In general, immersion cooling offers noteworthy advantages over conventional air-cooling methods as synthetic dielectric fluids have high heat dissipation capacities which are roughly about 1200 times greater than air. Other advantages of dielectric fluid immersion cooling include even thermal profile on chips, reduction in noise and addressing reliability and operational enhancements like whisker formation and electrochemical migration. Nevertheless, lack of data published and availability of long-term reliability data on immersion cooling is insufficient which makes most of data centers operators reluctant to implement this technique. The first part of this paper will compare thermal performance of single-phase oil immersion cooled HP ProLiant DL160 G6 server against air cooled server using computational fluid dynamics on 6SigmaET®. Focus of the study are major components of the server like Central Processing Unit (CPU), Dual in Line Memory Module (DIMM), Input/output Hub (IOH) chip and Input/output controller Hub (ICH). The second part of this paper focuses on thermal performance optimization of oil immersion cooled servers by varying inlet oil temperature, flow rate and using different fluid.

Passive Immersion Cooling of 3-D Stacked Dies

2007 ◽  
Author(s):  
Karl J. L. Geisler ◽  
Avram Bar-Cohen
Keyword(s):  
Natural Convection ◽  
Integrated Circuit ◽  
Printed Circuit Board ◽  
High Heat ◽  
Circuit Board ◽  
Electrical Performance ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Immersion Cooling ◽  
High Heat Transfer

Three-dimensional die stacking increases integrated circuit (IC) density, providing increased capabilities and improved electrical performance on a smaller printed circuit board (PCB) footprint area. However, these advantages come at the expense of higher volumetric heat generation rates and decreased thermal and mechanical access to the die areas. Passive immersion cooling, allowing for buoyancy-driven fluid flow between stacked dies, can provide high heat transfer coefficients directly on the die surfaces, can easily accommodate a wide variety of interconnect schemes, and is scalable to any number of dies. A methodology for the optimization of immersion cooled 3-D stacked dies is presented, including the effects of confinement on natural convection and channel boiling. Optimum die spacings for both single and two phase cooling with saturated FC-72 are found to be on the order of 0.5mm for typical microelectronics geometries and to yield heat densities of 10–50 W/cm3 in natural convection and 100–500 W/cm3 in channel boiling.

Reliability Considerations for Oil Immersion-Cooled Data Centers

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Jimil M. Shah ◽  
Richard Eiland ◽  
Pavan Rajmane ◽  
Ashwin Siddarth ◽  
Dereje Agonafer ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Cooling System ◽  
Chemical Properties ◽  
Cost Savings ◽  
Dielectric Strength ◽  
Mineral Oil ◽  
Circuit Board ◽  
Air Cooling ◽  
Immersion Cooling ◽  
Oil Immersion

The improved efficiency of mineral oil may offer simplicity in facility design compared to traditional air cooling and provide a means for cost savings. Despite its improved cooling efficiency and cost savings, a mineral oil immersion cooling technique is still not widely implemented and original equipment manufacturers are reluctant to jeopardize sales of existing air-based cooling system equipment. Only compelling physics regarding thermal performance of direct immersion cooling is not enough for data center operators. Many uncertainties and concerns persist regarding the effects of mineral oil immersion cooling on the reliability of information technology (IT) equipment both at the component and chassis level. This paper is a first attempt at addressing this challenge by reviewing the changes in physical and chemical properties of IT equipment materials like polyvinyl chloride (PVC), printed circuit board (PCB), and capacitors and characterizes the interconnect reliability of materials. The changes in properties of a mineral oil like kinematic viscosity and dielectric strength are also cited as important factors and discussed briefly. The changes in mechanical properties like elasticity, hardness, swelling, and creep are being shown in the paper for thermoplastic materials. The chemical reaction between material and mineral oil as a function of time and temperature is also conferred. The literature gathered on the subject and quantifiable data gathered by the authors provide the primary basis for this research document.

Electro-Thermal Codesign Methodology of an On-Board Electric Vehicle Charger

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Omri Tayyara ◽  
Carlos Da Silva ◽  
Miad Nasr ◽  
Amir Assadi ◽  
Kshitij Gupta ◽  
...  
Keyword(s):  
Electric Vehicle ◽  
Heat Dissipation ◽  
Printed Circuit Board ◽  
Experimental Tests ◽  
Design Guidelines ◽  
Circuit Board ◽  
System Level ◽  
Design And Optimization ◽  
Dynamics And Control ◽  
In Series

Abstract Significant advances are needed to optimize the charging speed, reliability, safety, and cost of today's conservatively designed electric vehicle (EV) charging systems. The design and optimization of these novel engineering systems require concurrent consideration of thermal and electrical phenomena, as well as component and system level dynamics and control to guarantee reliable continuous operation, scalability, and minimum footprint. This work addresses the concurrent thermal and electrical design constraints in a high-density, on-board, bidirectional charger with vehicle-to-grid (V2G), grid-to-vehicle (G2V), vehicle-to-house (V2H), and vehicle-to-vehicle (V2V) power transfer capabilities. The electrical design of this charger consists of DC–DC and DC–AC power stages connected in series. The power-stage circuits are implemented on a printed circuit board (PCB) with 16 surface-mount silicon carbide MOSFETs, three inductors, and one transformer. The main goal of this work is to investigate the interplay between the cooling architecture and the PCB layout, and the corresponding impact on the heat dissipation and parasitic inductance. This work compares the performance of three generations of this multifunctional charger that employ different design methodologies and proposes high-level design guidelines derived from multiphysics simulations and experimental tests.

Impact of Immersion Cooling on Thermo-Mechanical Properties of PCB’s and Reliability of Electronic Packages

2019 ◽  
Author(s):  
Shrinath Ramdas ◽  
Pavan Rajmane ◽  
Tushar Chauhan ◽  
Abel Misrak ◽  
Dereje Agonafer
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Thermal Management ◽  
Printed Circuit Board ◽  
Young's Modulus ◽  
Circuit Board ◽  
Management Technique ◽  
Electronic Packages ◽  
Immersion Cooling ◽  
Reliability Of Electronics

Abstract Immersion cooling is highly efficient thermal management technique and can potentially be used for thermal management of high-density data. However, to use this as a viable cooling technique, the effect of dielectric coolants on the reliability of server components needs to be evaluated. Previous work reported contradicting findings for Young’s modulus of PCBs, providing motivation for this work. This study focuses on effect of immersion cooling on the mechanical properties of printed circuit board (PCB) and its impact on reliability of electronic packages. Changes in thermo-mechanical properties like Young’s modulus (E), Glass transition temperature (Tg), of PCB and its layers due to aging in dielectric coolant are studied. Two types of PCBs using different material namely 370HR and 185HR are studied. To characterize Young’s modulus and Tg dynamic mechanical analyzer (DMA) is used. Major finding is Young’s modulus is decreasing for PCBs after immersion in dielectric coolant which is likely to increase reliability of electronics package.

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