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Heat Dissipation Capacity of Heat Sink Assembly with/without Vortex Generators Sheam-Chyun Lin1,a,Cheng-Ju Chang1,b, Fu-Yin Wang1,c, Horng-Ching Hsiao1,d Shiuh‐Kuang Yang2,e, Chun-Yu Hsiao1,f 1National Taiwan University of Science and Technology, Taipei, Taiwan 2National Sun Yat-Sen University, Kaohsiung, Taiwan asclynn@mail.ntust.edu.tw, bD9603301@mail.ntust.edu.tw, cD9703302@mail.ntust.edu.tw, dhsiao@ee.ntust.edu.tw,eskyang@mail.nsysu.edu.tw, fD9607101@mail.ntust.edu.tw Keywords: Vortex generators, Heat sink assembly, Numerical simulation, Thermal resistance Abstract.
In this research, numerical simulation is adopted to study the cooling characteristic of a bracket-type heat sink assembly.
As a result, the numerical simulations show thatapparent reductions on source temperature (from 348.0K to 346.2K) and thermal resistance (from 0.266 K/W to 0.253 K/W) are observed for a 150W power input.
The winglet vortexis placed in front of 3X5 modules with a 20° attack angle to enhance heat transfer coefficients, reduce thermal wake and module temperatures significantly.Leu et al.[5] used CFD and test meansto analyze heat transfer and flow field in the plate-fin and tube heat exchangers equippedwith vortex generators.
Numerical results of prototype CPU air cooler In this research, numerical simulation is adopted to analyze the heat dissipation capacity of prototype heat sink assembly (Fig. 1) under the high power input, say 150W.

The horizontal part, with a constant stress of 0.65MPa, in the stress-strain curve of the plaque was applied for the simulation of the non-recoverable deformation of the interlining, which was proved to be reasonable by the latter simulation.
A new constitutive model for the plaque was introduced, which made the results of the simulation closer to the real situation.
It can be concluded from the simulation that the distal end of stent may injure the artery wall after deployment, and the recoil ratios of the three models were very different.
So FEM is proved to be an especially useful numerical simulation method for quantifying some biomechanical characteristics of ICSI.
Furthermore, some researchers have used computational fluid dynamics (CFD) to explore the effect of stent implantation on blood flow.

Standard k-ε (SKE) and Large Eddy Simulation (LES) techniques were chosen as the turbulent model for the validation study.
Firstly, a steady state simulation using SKE was obtained and the steady state statistics was used as the initial conditions for the LES simulation.
The LES simulation is continued for 30 s of simulation time in order to establish the turbulent wind fields throughout the domain and all statistics are averaged at least for 15 s.
Carissimo, Best practice guideline for the CFD simulation of flows in the urban environment.
An Intercomparison of Large-Eddy Simulations of the Stable Boundary Layer, Bound-Lay Meteorol 11 (2006) 247-272.

The third one is simulation and discussion.
Simulation and Discussion We use ESI-CFD+ software package for simulation.
As in Figs. 4(a) and 4(b) for the geometric dimensions of hemi-spherical and square chambers, the thermal sensors can be put at either one of the three points to be trade-off by simulation.

The external wall and window’s heat load ratio to the total heat load case case 1 case 2 case 3 case 4 case 5 the external wall heat load ratio 20% 30% 40% 50% 60% the external window’s heat load ratio 80% 70% 60% 50% 40% Simulations The physical model.
The room space used in the CFD is 5.0 m in length, 4.0 m in width and 3.0 m in height.
This model is popular in industrial flow and heat transfer simulations because it is robustness, economy, and reasonable accuracy for a wide range of turbulent.
The simulation boundary conditions.
The parameter result of the different case case case 1 case 2 case 3 case 4 case 5 the total heating load (w) 407 407 407 407 407 the heat load of the external wall (w) 81.4 122.1 162.8 203.5 244.2 the heat load of the external window (w) 325.6 284.9 244.2 203.5 162.8 the external wall’s heat transfer coefficient (w/m2·k) 0.383 0.575 0.766 0.958 1.149 the external window’s heat transfer coefficient (w/m2·k) 3.261 2.853 2.446 2.038 1.631 the internal surface temperature of the external wall (˚C) 16.86 16.28 15.71 15.14 14.57 the internal surface temperature of the external window (˚C) 8.25 9.47 10.69 11.91 13.13 the supply-return heat water mean temperature (˚C) 52.59 52.59 52.59 52.59 52.59 The simulation results.

This paper calculated the flow and air pressure data when automatic angle modulation fan in different installation angle during operation by Fluent, so as to proof the practicality and superiority of automatic angle modulation cooling fan in the engine cooling. 1-engine, 2-output shaft, 3-pump, 4- automatic angle modulation equipment, 5-force conversation equipment, 6-bellows, 7-radiator, 8-bevel gear pair, 9-control flow pipe, 10-container of expansion liquid, 11container of cooling water Fig.1 The picture of engine cooling system Modeling The simulation model was built by the automatic angle modulation cooling fan designed for the engine of the ZL50C loader.
To reflect the running situation in the different installation angle in this test, the grid model of fan was built at the installation angle of 25°, 36°, 45°, 54°, 60°, 70°, 75°severally, the method of building and meshing is the same of every model at different angle, all above work is on the tool of Turbo that was exploited for the simulation of fan.
Fig.2 Flow area meshed model of single blade Simulation Import the seven meshed models into the Fluent, the average number of elements is about 300 thousand, use the solver of segregated and implicit, absolute velocity formulation, PRESTO!
The residual convergence of simulation to the 54°installation angle is shown as fig. 3, when it running with the inlet flow is 4.45kg/s, the nephogram of blade static pressure is shown as fig. 4.
Investigation on the Connection between Angles of Setting and Efficiency within Axial-flow Fan for Subway by CFD [J].

Rao et al. [7] performed numerical simulations of laminar flow of shear-thinning fluids modeled by the power-law model across elliptical section tubes.
In the present work, the heat transfer from elliptical section tubes arranged in a row to viscoplastic fluids in cross flow is investigated using computational fluid dynamics (CFD).
The measure of heat transfer provided in each case is given by the average Nusselt number based on the square root of the ellipse area, defined as , (10) where qw is the heat transfer rate of the tube wall, Le Is the ellipse perimeter calculated as [18] , (11) where e is the ellipse eccentricity, calculated as (12) For the numerical solution, the CFD ANSYS/FLUENT software was used.
In this work numerical simulations were carried out with meshes of different degrees of refinement and the obtained solutions were compared.
“Numerical simulation and global linear stability analysis of low-Re past a heated circular cylinder.”

A concise numerical model of gas-liquid stratified wavy flow LI Guozhen1,a,Yuan Yalei2,b 1China University of Petroleum,Beijing 102249,China 2Beijing Petroleum Machinery Factory,100083, China a guozhenli76@163.com, b kuku935@sohu.com Keywords: gas-liquid flow；stratified wavy flow；closure laws; numerical simulation Abstract.
Nigam: CFD modeling of flow profiles and interfacial phenomena Chemical Engineering and Processing 2006,45 : 55–65 [10] Gada, VH ,Sharma: A Analytical and level-set method based numerical study on oil-water smooth/wavy stratified-flow in an inclined plane-channel Int.J.Multiphase Flow, 2012; 38(1): 99-117 [11] Wang linlin,Tian hui,Li Guojun: Numeical simulation of oil-water and air-water two-phase flow based on level-set methods.

A geometric model and finite element grid model of JQ40A gasoline engine turbocharger were set up based on the CFD software NUMECA.
Compressor Impeller Strength Simulation Stress Analysis and Deformation Analysis of the Compressor Impeller.
Fig.4 Turbine structural design scheme (a) (b) Fig.5 Turbo stress simulation (a) (b) Modal Analysis of Turbine Blades.
Numerical Simulations of Stall inside a Centrifugal Compressor [J].
Numerical simulation of the flow field in diesel engine exhaust manifold based on FLENT[J].

In this study, we valid and apply a multi-function CFD (computational fluid dynamics) model we have recently developed to simulate the propagation and breaking of offshore waves, as well as their impacts on costal structures.
The simulation is continued for 6s with an automatically adapted time step using maximum CFL-numbers of 0.75.
Simulations were carried out to predict the breaking pattern for different seabed slopes and wave heights.
From numerical simulations conducted in this study, we have got the major understanding as follows. 1.
References [1] K.M.T Kleefsman, G.Fekken, A Volume-of-Fluid based simulation method for wave impact problems, J.