Design of Cooling Systems for Electronic Equipment Using Both Experimental and Numerical Inputs

2004 ◽  
Vol 126 (4) ◽  
pp. 465-471 ◽  
Author(s):  
Tunc Icoz ◽  
Yogesh Jaluria

This paper presents a methodology for the design and optimization of cooling systems for electronic equipment. In this approach, inputs from both experimentation and numerical modeling are to be used concurrently to obtain an acceptable or optimal design. The experimental conditions considered are driven by the numerical simulation and vice versa. Thus, the two approaches are employed in conjunction, rather than separately, as is the case in traditional design methods. Numerical simulation is used to consider different geometries, materials, and dimensions, whereas experiments are used for obtaining results for different flow rates and heat inputs, as these can often be varied more easily in experiments than in simulations. Also, transitional and turbulent flows are more accurately and more conveniently investigated experimentally. Thus, by using both approaches concurrently, the entire design domain is covered, leading to a rapid, convergent, and realistic design process. Two simple configurations of electronic cooling systems are used to demonstrate this approach.

Author(s):  
Tunc Icoz ◽  
Yogesh Jaluria

This paper presents a methodology for the design and optimization of the cooling system for electronic equipment. In this approach, inputs from both experimentation and numerical modeling are to be used concurrently to obtain an acceptable or optimal design. The experimental conditions considered are driven by the numerical simulation, and vice versa. Thus, the two approaches are employed in conjunction, rather than separately, as is the case in traditional design methods. Numerical simulation is used to consider different geometries, materials and dimensions, whereas experiments are used for obtaining results for different flow rates and heat inputs, since these can often be varied more easily in experiments than in simulations. Also, transitional and turbulent flows are more accurately and more conveniently investigated experimentally. Thus, by using both the approaches concurrently, the entire design domain is covered, leading to a rapid, convergent, and realistic design process. Two simple configurations of electronic cooling systems are used to demonstrate this approach.


This book provides students and researchers in fluid engineering with an up-to-date overview of turbulent flow research in the areas of simulation and modeling. A key element of the book is the systematic, rational development of turbulence closure models and related aspects of modern turbulent flow theory and prediction. Starting with a review of the spectral dynamics of homogenous and inhomogeneous turbulent flows, succeeding chapters deal with numerical simulation techniques, renormalization group methods and turbulent closure modeling. Each chapter is authored by recognized leaders in their respective fields, and each provides a thorough and cohesive treatment of the subject.


Author(s):  
Ehsan Dehdarinejad ◽  
Morteza Bayareh ◽  
Mahmud Ashrafizaadeh

Abstract The transfer of particles in laminar and turbulent flows has many applications in combustion systems, biological, environmental, nanotechnology. In the present study, a Combined Baffles Quick-Separation Device (CBQSD) is simulated numerically using the Eulerian-Lagrangian method and different turbulence models of RNG k-ε, k-ω, and RSM for 1–140 μm particles. A two-way coupling technique is employed to solve the particles’ flow. The effect of inlet flow velocity, the diameter of the splitter plane, and solid particles’ flow rate on the separation efficiency of the device is examined. The results demonstrate that the RSM turbulence model provides more appropriate results compared to RNG k-ε and k-ω models. Four thousand two hundred particles with the size distribution of 1–140 µm enter the device and 3820 particles are trapped and 380 particles leave the device. The efficiency for particles with a diameter greater than 28 µm is 100%. The complete separation of 22–28 μm particles occurs for flow rates of 10–23.5 g/s, respectively. The results reveal that the separation efficiency increases by increasing the inlet velocity, the device diameter, and the diameter of the particles.


2019 ◽  
Vol 3 (3) ◽  
pp. 73 ◽  
Author(s):  
Mohamad Karaki ◽  
Rafic Younes ◽  
Francois Trochu ◽  
Pascal Lafon

A great amount of attention has been given to the evaluation of the permeability tensor and several methods have been implemented for this purpose: experimental methods, as well as numerical and analytical methods. Numerical simulation tools are being seriously developed to cover the evaluation of permeability. However, the results are still far from matching reality. On the other hand, many problems still intervene in the experimental measurement of permeability, since it depends on several parameters including personal performance, preparation of specimens, equipment accuracy, and measurement techniques. Errors encountered in these parameters may explain why inconsistent measurements are obtained which result in unreliable experimental evaluation of permeability. However, good progress was done in the second international Benchmark, wherein a method to measure the in-plane permeability was agreed on by 12 institutes and universities. Critical researchers’ work was done in the field of analytical methods, and thus different empirical and analytical models have emerged, but most of those models need to be improved. Some of which are based on Cozeny-Karman equation. Others depend on numerical simulation or experiment to predict the macroscopic permeability. Also, the modeling of permeability of unidirectional fiber beds have taken the greater load of concern, whereas that of fiber bundle permeability prediction remain limited. This paper presents a review on available methods for evaluating unidirectional fiber bundles and engineering fabric permeability. The progress of each method is shown in order to clear things up.


2012 ◽  
Vol 45 (4) ◽  
pp. 674-678 ◽  
Author(s):  
Lukas Lomb ◽  
Jan Steinbrener ◽  
Sadia Bari ◽  
Daniel Beisel ◽  
Daniel Berndt ◽  
...  

Serial femtosecond crystallography (SFX) using X-ray free-electron laser (FEL) sources has the potential to determine the structures of macromolecules beyond the limitation of radiation damage and without the need for crystals of sufficient size for conventional crystallography. In SFX, a liquid microjet is used to inject randomly oriented crystals suspended in their storage solution into the FEL beam. Settling of crystals in the reservoir prior to the injection has been found to complicate the data collection. This article details the development of an anti-settling sample delivery instrument based on a rotating syringe pump, capable of producing flow rates and liquid pressures necessary for the operation of the injector. The device has been used successfully with crystals of different proteins, with crystal sizes smaller than 20 µm. Even after hours of continuous operation, no significant impairment of the experiments due to sample settling was observed. This article describes the working principle of the instrument and sets it in context with regard to the experimental conditions used for SFX. Hit rates for longer measuring periods are compared with and without the instrument operating. Two versions of the instrument have been developed, which both deliver sample at a constant flow rate but which differ in their minimum liquid flow rates and maximum pressures.


2011 ◽  
Vol 64 (2) ◽  
Author(s):  
Giancarlo Alfonsi

The direct numerical simulation of turbulence (DNS) has become a method of outmost importance for the investigation of turbulence physics, and its relevance is constantly growing due to the increasing popularity of high-performance-computing techniques. In the present work, the DNS approach is discussed mainly with regard to turbulent shear flows of incompressible fluids with constant properties. A body of literature is reviewed, dealing with the numerical integration of the Navier-Stokes equations, results obtained from the simulations, and appropriate use of the numerical databases for a better understanding of turbulence physics. Overall, it appears that high-performance computing is the only way to advance in turbulence research through the front of the direct numerical simulation.


Author(s):  
Keyong Cheng ◽  
Xiulan Huai ◽  
Jun Cai ◽  
Zhixiong Guo

In the present study, numerical simulation is carried out for impingement/effusion cooling on the leading edge of a turbine blade similar to an experimental model tested previously. The k-ε turbulence model is used, and simulation parameters are set in accordance with the experimental conditions, including temperature ratio, blowing ratio, and Reynolds number of the main stream. The accuracy and reliability of the simulation is verified by the experimental data, and the influence of various factors on fluid flow and heat transfer is analyzed in detail. The results indicate that the blowing ratio is one critical factor which affects the cooling effectiveness. The greater the blowing ratio is, the higher the cooling effectiveness is. In addition, a staggered-holes arrangement is numerically studied and compared with a line-holes arrangement. The results show that the staggered-holes arrangement has a lower temperature on the outer surface of the leading edge and has improved the cooling effectiveness.


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