scholarly journals Use of a Two-Dimensional Simulation Model in the Thermal Analysis of a Multi-Board Electronic Module

1994 ◽  
Vol 116 (2) ◽  
pp. 126-133 ◽  
Author(s):  
C. Beckermann ◽  
T. F. Smith ◽  
B. Pospichal
Keyword(s):  
Heat Transfer ◽  
Simulation Model ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Circuit Boards ◽  
Depth Direction ◽  
Wide Range ◽  
Local Board ◽  
Dimensional Simulation ◽  
Effective Component

A study is reported of heat transfer and air flow in an electronic module consisting of an array of narrowly spaced vertical circuit boards with highly-protruding components contained in a naturally vented chassis. A two-dimensional simulation model is developed that accounts for heat transfer by conduction, convection, and radiation, and sensitivity studies are performed. Experiments are conducted using a specially constructed test module. Comparisons with the experiments reveal the need to calibrate the model by selecting an effective component height that represents the drag properties of the actual three-dimensional component geometry. The need to account in the model for heat losses in the depth direction is also discussed. The importance of accurate thermophysical properties and of multi-dimensional radiation is shown. Good agreement with measured velocities and local board temperatures is obtained over a wide range of power levels, and it is concluded that the calibrated model is capable of representing the thermal behavior of the present module.

Numerical Simulation of Heat Transfer in Shear Flow of Liquid-Solid Two-Phase Media by Immersed Solid Approach

2015 ◽  
Author(s):  
Takeo Kajishima ◽  
Katsuya Kondo ◽  
Shintaro Takeuchi
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermal Convection ◽  
Heat Conductivity ◽  
Three Dimensional ◽  
Effect Of Temperature ◽  
Two Dimensional ◽  
Two Phase ◽  
Dimensional Simulation ◽  
Conductive Particles

We developed a direct numerical simulation (DNS) method of solid-fluid two-phase flows to study the effects of heat conductivity within a solid particle and the particle motion on the heat transfer. Heat transfer and particle behaviors were studied for different ratios of heat conductivity (solid to liquid) and solid volume fractions. The simulation results emphasize the effect of temperature distributions within the particles, and the heat transfer through each particle plays an important role for the motion of the particulate flow. The particle-laden flow in a two-dimensional channel of instable thermal stratification, namely hot wall at the bottom and cold wall at the top, is simulated. In the two-dimensional computation, the heat transfer attenuates by increasing the neutral conductive particles because of the resistance to the thermal convection. In case of highly conductive particles, the thermal convection and conductions are enhanced to some extent of addition but the overload of particles suddenly reduces the intensity of convection, resulting in the lower heat transfer. The inverse gradient of mean temperature is observed particularly in case of moderate loading of neutral conductive particles. It is due to the modulation of the profile of convection cells. Most of the above-mentioned findings are reproduced by the fully three-dimensional simulation.

Natural Convection in a Partitioned Cubic Enclosure

1992 ◽  
Vol 114 (2) ◽  
pp. 410-417 ◽  
Author(s):  
K. C. Karki ◽  
P. S. Sathyamurthy ◽  
S. V. Patankar
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Flow And Heat Transfer ◽  
Dimensional Simulation ◽  
Oriented Parallel ◽  
Rayleigh Numbers

Numerical solutions are obtained for fluid flow and heat transfer in a cubic enclosure with a vertical adiabatic partition. The two zones of the enclosure are connected by a single rectangular opening. The partition is oriented parallel to the isothermal sidewalls, one of which is heated and the other cooled while the remaining walls are adiabatic. Results have been presented for air for the Rayleigh numbers in the range 104−107. The width of the opening is held fixed while the height, relative to the enclosure height, is varied from 0.25 to 0.75. The effects of various parameters on the flow structure and heat transfer are investigated. The results of the three-dimensional simulation have also been compared with those for the corresponding two-dimensional configurations.

scholarly journals Two Dimensional CFD Analysis and Flow Optimization of Transmission Cooling Scoop for Longitudinal Powertrain Applications

2021 ◽  
Vol 2 (1) ◽  
pp. 11-21
Author(s):  
Jacob Viertel ◽  
Rachmadian Wulandana
Keyword(s):  
Heat Transfer ◽  
Energy Input ◽  
Three Dimensional ◽  
Ambient Air ◽  
Future Research ◽  
Two Dimensional ◽  
Flow Optimization ◽  
Future Design ◽  
Cooling Method ◽  
Dimensional Simulation

Two dimensional finite area method simulation was conducted to optimize the convective cooling performance of a transmission cooling scoop for longitudinal vehicle powertrain applications. Cooling of the transmission in an automobile is important to prevent premature wear or sudden failure caused by prolonged overheating of internal transmission components. The most common method for transmission cooling requires a small energy input for powering a pump to cool the transmission by circulating transmission fluid through a heat exchanger. An alternative cooling method was designed utilizing a simple scoop geometry to induce forced convection from ambient air to cool the transmission with no energy input requirement. Two dimensional simulation of this alternative cooling method was conducted in ANSYS Fluent. Fluid flow and heat transfer performance were analyzed for three proposed cooling scoop designs. Further flow optimization was achieved with parametric study regarding angle at which the cooling scoop is positioned relative to the transmission. Three dimensional simulation was conducted for improved observation of the physical model. Based on the simulation results, optimal geometry and future design improvements have been determined. A peak simulated heat transfer of 11.14 kW/m^2 was achieved with scoop angle of 45 degrees. Future research investigating the effects of induced turbulence to improve convective heat transfer would be beneficial.

Effective Particle Size Representation for Erosion Wear in Centrifugal Pump Casings

2017 ◽  
Author(s):  
Krishnan V. Pagalthivarthi ◽  
John M. Furlan ◽  
Robert J. Visintainer
Keyword(s):  
Particle Size ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computation Time ◽  
Particle Simulation ◽  
Computational Time ◽  
Two Dimensional ◽  
Wide Range ◽  
Dimensional Simulation ◽  
Three Dimensional Simulations

For the purpose of Computational Fluid Dynamic (CFD) simulations, the broad particle size distribution (PSD) encountered in industrial slurries is classified into a discrete number of size classes. Since mono-size simulations consume much less computational time, especially in 3D simulations, it would be advantageous to determine an equivalent single particle size representation which yields the same wear distribution predictions as the multi-size simulations. This work extends the previous two-dimensional study [1], which was for a specific PSD slurry flow through three selected pumps, to determine an effective equivalent mono-size representation. The current study covers two-dimensional simulations over a wide range of pumps of varying sizes (40 pumps), 2 inlet concentrations and 4 different particle size distributions. Comparison is made between the multi-size wear prediction and different possible representative mono-size particle wear predictions. In addition, a comparison of multi-size and different mono-size results using three dimensional simulations is also shown for a typical slurry pump as a sample case to highlight that the conclusions drawn for two dimensional simulation could hold good for three dimensional simulations as well. It is observed that by using a mono-size equivalent, the computation time is 20–25% of the computation time for multi-size (6-particle) simulation.

scholarly journals Numerical Analysis on Enhancing Spray Performance of SCR Mixer Device and Heat Transfer Performance Based on Field Synergy Principle

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 786
Author(s):  
Jiedong Ye ◽  
Junshuai Lv ◽  
Dongli Tan ◽  
Zhiqiang Ai ◽  
Zhiqiang Feng
Keyword(s):  
Heat Transfer ◽  
Conversion Rate ◽  
Water Solution ◽  
Three Dimensional ◽  
Field Synergy ◽  
Field Synergy Principle ◽  
Spray System ◽  
Injection Methods ◽  
Wall Injection ◽  
Dimensional Simulation

The NH3 uniformity and conversion rate produced by the urea–water solution spray system is an essential factor affecting de-NOx efficiency. In this work, a three-dimensional simulation model was developed with the CFD software and was employed to investigate the effects of two typical injection methods (wall injection and center injection) and three distribution strategies (pre-mixer, post-mixer, pre-mixer, and post-mixer) of two typical mixers on the urea conversion rate and uniformity. The field synergy principle was employed to analyze the heat transfer of different mixer flow fields. The results show that the single mixer has instability in optimizing different injection positions due to different injection methods and injection positions. The dual-mixer is stable in the optimization of the flow field under different conditions. The conclusion of the field synergy theory of the single mixer accords with the simulation result. The Fc of the dual-mixer cases is low, but the NH3 conversion and uniformity index rate are also improved due to the increase in the residence time of UWS.

scholarly journals Effect of buried depth on thermal performance of a vertical U-tube underground heat exchanger

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 327-330
Author(s):  
Li Yang ◽  
Bo Zhang ◽  
Jiří Jaromír Klemeš ◽  
Jie Liu ◽  
Meiyu Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Simplified Model ◽  
Two Dimensional ◽  
Construction Sites ◽  
Full Size ◽  
Unit Depth ◽  
Research Show

Abstract Many researchers numerically investigated U-tube underground heat exchanger using a two-dimensional simplified pipe. However, a simplified model results in large errors compared to the data from construction sites. This research is carried out using a three-dimensional full-size model. A model validation is conducted by comparing with experimental data in summer. This article investigates the effects of fluid velocity and buried depth on the heat exchange rate in a vertical U-tube underground heat exchanger based on fluid–structure coupled simulations. Compared with the results at a flow rate of 0.4 m/s, the results of this research show that the heat transfer per buried depth at 1.0 m/s increases by 123.34%. With the increase of the buried depth from 80 to 140 m, the heat transfer per unit depth decreases by 9.72%.

Heat and Mass Transfer in an Incompressible Turbulent Boundary Layer

1972 ◽  
Vol 94 (1) ◽  
pp. 23-28 ◽  
Author(s):  
E. Brundrett ◽  
W. B. Nicoll ◽  
A. B. Strong
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Porous Plate ◽  
Mixing Length ◽  
Two Dimensional ◽  
Transfer Data ◽  
Incompressible Turbulent Boundary Layer ◽  
Wide Range ◽  
Incompressible Boundary

The van Driest damped mixing length has been extended to account for the effects of mass transfer through a porous plate into a turbulent, two-dimensional incompressible boundary layer. The present mixing length is continuous from the wall through to the inner-law region of the flow, and although empirical, has been shown to predict wall shear stress and heat transfer data for a wide range of blowing rates.

Direct simulation of evolution and control of three-dimensional instabilities in attachment-line boundary layers

1995 ◽  
Vol 291 ◽  
pp. 369-392 ◽  
Author(s):  
Ronald D. Joslin
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Computationally Efficient ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
Attachment Line

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier–Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

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