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

2003 ◽  
Author(s):  
Vale´rie Eveloy ◽  
Peter Rodgers ◽  
M. S. J. Hashmi
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Thermal Analysis ◽  
Computational Fluid Dynamics ◽  
Printed Circuit Boards ◽  
Turbulence Models ◽  
Electronic Component ◽  
Thermal Design ◽  
Junction Temperature ◽  
Temperature Prediction

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.

An Investigation Into the Potential of Low-Reynolds Number Eddy Viscosity Turbulent Flow Models to Predict Electronic Component Operational Temperature

2005 ◽  
Vol 127 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Peter Rodgers ◽  
Vale´rie Eveloy ◽  
M. S. J. Hashmi
Keyword(s):  
Thermal Analysis ◽  
Reynolds Number ◽  
Eddy Viscosity ◽  
Predictive Accuracy ◽  
Low Reynolds Number ◽  
Turbulence Models ◽  
Thermal Design ◽  
Junction Temperature ◽  
Temperature Prediction ◽  
Low Reynolds

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 electronic boards. This limitation has been previously highlighted (Eveloy, V. et al., 2004, IEEE Trans. Compon., Packag., Technol. 27, pp. 268–282), with component junction temperature prediction errors of up to 35% reported. This study evaluates the potential of three candidate low-Reynolds number eddy viscosity turbulence models to improve predictive accuracy. An array of fifteen board-mounted PQFPs is analyzed in a 4 m/s airflow. Using the shear stress transport k-ω model, significant improvements in component junction temperature prediction accuracy are obtained relative to the standard high-Reynolds number k-ε 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.

scholarly journals Thermal Analysis and Optimization of Nano Coated Radiator Tubes Using Computational Fluid Dynamics and Taguchi Method

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 804
Author(s):  
Sudalai Suresh Pungaiah ◽  
Chidambara Kuttalam Kailasanathan
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Thermal Analysis ◽  
Computational Fluid Dynamics ◽  
Orthogonal Array ◽  
Heat Dissipation ◽  
Heat Removal ◽  
Taguchi Methods ◽  
Coolant Fluid ◽  
The Impact

Automotive heat removal levels are of high importance for maximizing fuel consumption. Current radiator designs are constrained by air-side impedance, and a large front field must meet the cooling requirements. The enormous demand for powerful engines in smaller hood areas has caused a lack of heat dissipation in the vehicle radiators. As a prediction, exceptional radiators are modest enough to understand coolness and demonstrate great sensitivity to cooling capacity. The working parameters of the nano-coated tubes are studied using Computational Fluid Dynamics (CFD) and Taguchi methods in this article. The CFD and Taguchi methods are used for the design of experiments to analyse the impact of nano-coated radiator parameters and the parameters having a significant impact on the efficiency of the radiator. The CFD and Taguchi methodology studies show that all of the above-mentioned parameters contribute equally to the rate of heat transfer, effectiveness, and overall heat transfer coefficient of the nanocoated radiator tubes. Experimental findings are examined to assess the adequacy of the proposed method. In this study, the coolant fluid was transmitted at three different mass flow rates, at three different coating thicknesses, and coated on the top surface of the radiator tubes. Thermal analysis is performed for three temperatures as heat input conditioning for CFD. The most important parameter for nanocoated radiator tubes is the orthogonal array, followed by the Signal-to-Noise Ratio (SNRA) and the variance analysis (ANOVA). A proper orthogonal array is then selected and tests are carried out. The findings of ANOVA showed 95% confidence and were confirmed in the most significant parameters. The optimal values of the parameters are obtained with the help of the graphs.

Computational Fluid Dynamics and Thermal Analysis of Leaf Seals for Aero-engine Application

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Vincenzo Fico ◽  
Michael J. Pekris ◽  
Christopher J. Barnes ◽  
Rakesh Kumar Jha ◽  
David Gillespie
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Thermal Analysis ◽  
Computational Fluid Dynamics ◽  
Reynolds Number ◽  
Boundary Conditions ◽  
Thermal Boundary Conditions ◽  
Leaf Pack ◽  
Aero Engine

Aero-engine gas turbine performance and efficiency can be improved through the application of compliant shaft seal types to certain sealing locations within the secondary air system. Leaf seals offer better performance than traditional labyrinth seals, giving lower leakage flows at design duties. However, for aero-engine applications, seal designs must be able to cope with relatively large off-design seal closures and closure uncertainties. The two-way coupling between temperatures of seal components and seal closures, through the frictional heat generated at the leaf–rotor interface when in contact, represents an important challenge for leaf seal analysis and design. This coupling can lead to leaf wear and loss, rotor overheating, and possibly to unstable sealing system behavior (thermal runaway). In this paper, we use computational fluid dynamics (CFD), finite element (FE) thermal analysis, and experimental data to characterize the thermal behavior of leaf seals. This sets the basis for a study of the coupled thermomechanical behavior. CFD is used to understand the fluid-mechanics of a leaf pack. The leaf seal tested at the Oxford Osney Laboratory is used for the study. Simulations for four seal axial Reynolds number are conducted; for each value of the Reynolds number, leaf tip-rotor contact, and clearance are considered. Distribution of mass flow within the leaf pack, distribution of heat transfer coefficient (HTC) at the leaf surface, and swirl velocity pick-up across the pack predicted using CFD are discussed. The experimental data obtained from the Oxford rig is used to develop a set of thermal boundary conditions for the leaf pack. An FE thermal model of the rig is devised, informed by the aforementioned CFD study. Four experiments are simulated; thermal boundary conditions are calibrated to match the predicted metal temperatures to those measured on the rig. A sensitivity analysis of the rotor temperature predictions to the heat transfer assumptions is carried out. The calibrated set of thermal boundary conditions is shown to accurately predict the measured rotor temperatures.

Computational Fluid Dynamics Prediction of Heat Transfer in Rod Bundles With Water at Supercritical Pressure

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Andrea Pucciarelli ◽  
Walter Ambrosini
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbulence Models ◽  
Supercritical Pressure ◽  
Navier Stokes ◽  
Rod Bundles ◽  
Experimental Conditions ◽  
Heat Transfer Deterioration ◽  
Spacer Grids

The paper further explores the application of computational fluid dynamics (CFD) codes for the study of the heat-transfer phenomena involved when working with fluids at supercritical pressure; bundle analysis is considered here in particular. As for previous simulations performed by the authors considering heat-transfer deterioration inside heated tubes, this application points out the limited capabilities of the most commonly used Reynolds-averaged Navier–Stokes models when approaching the heat-transfer deterioration phenomenon. It must be noted that some of the considered experimental conditions, which are very close to the pseudocritical temperature, represent at the same time one of the most challenging situations for the CFD codes and a very common situation if supercritical water-cooled reactors (SCWRs) will be developed. Improvements of the currently available turbulence models are then needed. The paper analyzes the most likely causes of the observed insufficient quality of the obtained predictions. In addition to comparing the measured and calculated wall temperature trends, the effect of the presence of the spacer grids on the turbulent flow is considered. Spacers are in fact very important to assure the structural stability of fuel, though they also affect the flow, generally improving the turbulence conditions in their neighborhood and slightly impairing it in the downstream region. A comparison between predictions performed including or not including the spacers is also performed.

Computational fluid dynamics and experimental study of turbulent natural convection with surface thermal radiation in a cubic enclosure

2020 ◽  
Vol 31 (05) ◽  
pp. 2050065
Author(s):  
J. M. A. Navarro ◽  
J. F. Hinojosa ◽  
I. Hernández-López
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Experimental Study ◽  
Computational Fluid Dynamics ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Turbulence Models ◽  
Numerical Results ◽  
Turbulent Natural Convection

This paper reports a computational fluid dynamics and experimental study to analyze the effect of surface thermal radiation on the turbulent natural convection in a closed cubic cavity. Experimental and numerical results are compared for low and high wall emissivities. Experimental temperature profiles were obtained at six different depths and heights consisting of 14 thermocouples each. Several turbulence models were evaluated against experimental data. It was found that renormalized [Formula: see text]-[Formula: see text] and standard [Formula: see text]-[Formula: see text] turbulence models present the best agreement with the experimental data for emissivities of walls of 0.98 and 0.03, respectively. Thus, the numerical results of temperature fields and flow patterns were obtained with these models. From the results, it was found that the effect of thermal radiation on experimental heat transfer coefficients is significantly, increased between 48.7% ([Formula: see text]) and 50.16% ([Formula: see text]), when the emissivity of the walls increases from 0.03 to 0.98. Therefore, the radiative exchange should not be neglected in heat transfer calculations in cubic enclosures, even if the temperature difference between heated wall and cold wall is relatively small (between 15 and 30[Formula: see text]K).

The Effect of Different Turbulence Models on the Emitter Discharge by Using Computational Fluid Dynamics

2013 ◽  
Vol 662 ◽  
pp. 586-590
Author(s):  
Gang Lu ◽  
Qing Song Yan ◽  
Bai Ping Lu ◽  
Shuai Xu ◽  
Kang Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Turbulence Models ◽  
Experimental Results ◽  
Turbulent Model ◽  
Simulation Results ◽  
Rsm Model ◽  
Dynamics Method ◽  
Emitter Discharge

Four types of Super Typhoon drip emitter with trapezoidal channel were selected out for the investigation of the flow field of the channel, and the CFD (Computational Fluid Dynamics) method was applied to simulate the micro-field inside the channel. The simulation results showed that the emitter discharge of different turbulent model is 4%-14% bigger than that of the experimental results, the average discharge deviation of κ-ω and RSM model is 5, 4.5 respectively, but the solving efficiency of the κ-ω model is obviously higher than that of the RSM model.

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