Screen characterization under fan induced swirl conditions

Nevelsteen, Koen; Baelmans, Martine; Troch, Kris De; Mesbah, Majid; Nelemans, W.

doi:10.1109/stherm.2003.1194332

Cited by 9 publications

(3 citation statements)

References 5 publications

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“…Physical uncertainties include, for example, power dissipation for the various system units, and grilles and vents pressure loss coefficients [34]. In addition, the capability o f the CFD code to predict complex flow phenomena, such as fan-induced, and their impact on heat transfer needs to be considered [24,44,45], This is often compounded by the fact that in the early design phase, the CFD user may have little or no a priori knowledge of the flow regime, whether laminar, transitional, turbulent, and whether steady or unsteady. Such an uncertainty typically arises from the absence o f a physical prototype, and the difficulty in defining a characteristic dimension, hence transition Reynolds number, that adequately describes the heat transfer characteristics over the PCB or sub-system considered.…”

Section: Prediction Of Electronic Component Operational Temperaturementioning

confidence: 99%

“…Fan-generated flows contain swirling flow patterns [44], while screen holes will produce jets downstream [24,45]. Such flow disturbances can generate unsteady or transitional flow conditions over electronic circuit boards, with attaching, separating and recirculating flow features [60], In addition, the component topology often generates multi-dimensional flow phenomena that include pulsating and vortical structures [60,61].…”

Section: Prediction Of Electronic Component Operational Temperaturementioning

confidence: 99%

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An Experimental Assessment of Computational Fluid Dynamics Predictive Accuracy for Electronic Component Operational Temperature

Eveloy¹,

Rodgers²,

Hashmi

2003

Heat Transfer: Volume 3

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The flow modeling approaches employed in Computational Fluid Dynamics (CFD) codes dedicated to the thermal analysis of electronic equipment are generally not specific for the analysis of forced airflows over populated Printed Circuit Boards. This limitation has been previously highlighted [1], with component junction temperature prediction errors of up to 35% reported. This study evaluates the predictive capability of candidate turbulence models more suited to the analysis of electronic component heat transfer. Significant improvements in component junction temperature prediction accuracy are obtained, relative to a standard high-Reynolds number k-e model, which are attributed to better prediction of both board leading edge heat transfer and component thermal interaction. Such improvements would enable parametric analysis of product thermal performance to be undertaken with greater confidence in the thermal design process, and the generation of more accurate temperature boundary conditions for use in Physics-of-Failure based reliability prediction methods. The case is made for vendors of CFD codes dedicated to the thermal analysis of electronics to consider the adoption of eddy viscosity turbulence models more suited to board-level analysis.

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Section: Prediction Of Electronic Component Operational Temperaturementioning

confidence: 99%

Section: Prediction Of Electronic Component Operational Temperaturementioning

confidence: 99%

An Experimental Assessment of Computational Fluid Dynamics Predictive Accuracy for Electronic Component Operational Temperature

Eveloy¹,

Rodgers²,

Hashmi

2003

Heat Transfer: Volume 3

View full text Add to dashboard Cite

show abstract

“…If the screen is modeled as a planar resistance, the single pressure loss coefficient of the screen will affect the axial component of the flow, and as a result the flow will be more parallel to the screen, which does not happen in a real case. Nevelsteen et al (2006) went further, and they modeled only one case as a volumetric resistance, which was experimentally validated by obtaining a good level of adjustment. However, there were no correlations of the different pressure loss coefficients as a function of the different parameters.…”

Section: Introductionmentioning

confidence: 99%

Influence of Geometrical Parameters in The Downstream Flow of A Screen Under Fan-Induced Swirl Conditions

Bengoechea

Antón

Larraona

et al. 2014

Engineering Applications of Computational Fluid Mechanics

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A perforated plate placed downstream of an axial fan in order to avoid electromagnetic interferences (push cooling) is a common assembly in electronic systems. Because of the swirling component that the flow approaching the screen has, there is no accuracy in knowing how the screen affects the flow pattern downstream of the screen and the pressure drop through the screen. Since cooling capacity is related to velocity, the placement of the components downstream of the screen will be related to the velocity magnitude. Thus, properly predicting the flow pattern is highly important, and the results of this work may serve a good guideline for thermal designers to surmount this challenge. In order to establish how the screen affects the flow pattern, a parametric study is carried out. This study is performed by a Central Composite Face-centered (CCF) Design of Experiment (DoE), which demanded 81 Computational Fluid Dynamics (CFD) simulations and for which the Reynolds Stress Transport Model (RSTM) was used as a turbulence model. Thanks to the numerical results, the influence that different operational and geometrical parameters have on the flow pattern downstream of a screen and on the total pressure drop is analyzed. The swirl that the flow has at the inlet is found to be related to the screen's capacity to homogenize the flow downstream of the screen, as its thickness plays an important role in the flow's tangential component destruction. The main effects of the parameters and the interactions between them are shown. At the same time, through DoE techniques, different reduced models that predict how the flow pattern changes because of the screen are presented as useful tools for thermal designers.

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Analysis of the performance reduction of axial fans in close proximity to EMC screens

Antón

Bengoechea

Masip

et al. 2010

2010 11th International Thermal, Mechanical &Amp; Multi-Physics Simulation, and Experiments in Microelectronics and Microsystem

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Screen characterization under fan induced swirl conditions

Cited by 9 publications

References 5 publications

An Experimental Assessment of Computational Fluid Dynamics Predictive Accuracy for Electronic Component Operational Temperature

An Experimental Assessment of Computational Fluid Dynamics Predictive Accuracy for Electronic Component Operational Temperature

Influence of Geometrical Parameters in The Downstream Flow of A Screen Under Fan-Induced Swirl Conditions

Analysis of the performance reduction of axial fans in close proximity to EMC screens

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