Cooling System for a Portable Bio-Industry Centrifuge

Cfd Model ◽

Separate Species ◽

Zero Degree ◽

Reduced Temperature ◽

A centrifuge is used in bio-industry to separate species in blood and other chemicals. Bio-industry requires a temperature of zero degree centigrade in the rotor compartment of a centrifuge where samples are placed. In general, the current portable centrifuge systems generate a temperature of about 22 °C in the rotor compartment when operating at 3000 RPM. The motor and the electronics are the primary sources of the heat generation in such centrifuge. The aim of this study is to develop an appropriate cooling system for a specific portable centrifuge used in separating bioparticles that generates a total heat of approximately 43 W. Experimental, analytical and computer simulation were employed to achieve the project objective of reducing and maintaining the rotor compartment temperature at zero degree C. The CFD code Simulation model predicted rotor compartment temperatures that were in good agreement with those of the experimental measurements within 3%. Having confidence in the CFD model, simulation was carried out to incorporate four TEC units that are embedded on the surface of the rotor compartment resulting in reduced temperature to zero degree C.

Computational Fluid Dynamics Model of Air Velocity through a Poultry Transport Trailer in a Holding Shed

Applied Engineering in Agriculture ◽

10.13031/aea.13848 ◽

2020 ◽

Vol 36 (6) ◽

pp. 963-973

Author(s):

Christian L. Heymsfield ◽

Yi Liang ◽

Thomas A. Costello

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Cooling System ◽

Model Simulation ◽

List Type ◽

Cfd Model ◽

Dynamics Modeling ◽

Air Velocity ◽

Space Module ◽

Alternative Design

HighlightsComputational fluid dynamics modeling was an effective tool to simulate conditions on transport trailers in holding broilers for slaughter, to understand the performance of existing and alternative system configurations;Model simulation and measurements indicated that less than 32% of airflow generated by the cooling fans in the existing fan configuration in this study actually penetrated through the bird-occupied spaces;Simulations suggest that higher air velocity in the bird occupied zone within the modules can be achieved by alternative fan configurations at the holding shed, such as employing one fan per module, or with the addition of a transition enclosures from each fan outlet to the face of the receiving module. Abstract. The configuration of cooling systems in commercial holding sheds, where live broilers wait in cage modules for slaughter, varies between processing plants, with cooling system efficacies largely unknown. A computational fluid dynamics (CFD) model was developed to simulate airflow through cage modules in a poultry trailer in a typical holding shed configuration. Three alternative design configurations were simulated in order to better understand the air velocity profiles and to explore potential improvements for better cooling performance. Experimental data were collected within modules in a poultry trailer, parked in an existing commercial holding shed during warm summer conditions. Results from the CFD model had reasonable agreement with measured field data. Simulated air velocities were mostly within one standard deviation of measured values. Simulation of airflow through modules in the base configuration showed that less than 32% of airflow from the fans actually penetrated through the bird-occupied space. Module tiers experienced different airflow penetration due to the ad hoc positioning/alignment of the fans relative to the modules. In the base industry configuration, fans were in fixed positions and the number of fans and their centerline discharge axes did not align with the modules on the trailer. Regions not aligned with the faces of the fans, such as the uppermost and bottommost tiers, and horizontal locations offset from the fans, received the least airflow through the modules. Sections of modules experienced lower air velocity with increasing distance from the fans. Simulation of Design Alternative 2 (which added additional fans so that a fan was centered on each row) predicted an improved fan airflow of 3.08 and 3.05 kg s-1 through the cages in two adjacent rows, compared to 1.52 and 2.15 kg s-1 predicted for the original configuration. The increased air velocity using the alternative design illustrates the potential improvement and need to further optimize the design of these holding sheds. This research showed that a CFD model is an effective tool to simulate airflow conditions on poultry trailers in holding sheds to explore various holding shed cooling configurations and strategies. Keywords: Air velocity, CFD, Poultry Transportation, Poultry welfare.

Experimentally Validated Computational Fluid Dynamics Model for a Data Center With Cold Aisle Containment

Journal of Electronic Packaging ◽

10.1115/1.4029344 ◽

2015 ◽

Vol 137 (2) ◽

Cited By ~ 21

Author(s):

Sami A. Alkharabsheh ◽

Bahgat G. Sammakia ◽

Saurabh K. Shrivastava

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Rate ◽

Data Center ◽

Flow Distribution ◽

Temperature Measurements ◽

Air Conditioner ◽

Cfd Model ◽

This paper presents the results of an experimentally validated computational fluid dynamics (CFD) model for a data center with fully implemented fan curves on both the servers and the computer room air conditioner (CRAC). Both open and contained cold aisle systems are considered in this study. This work is divided into sections for the baseline system (prior to installing containment) calibration and the fully contained cold aisle system calibration and leakage characterization. In the open system, the fan curve of the CRAC unit is extracted from the manufacturer data, while the fan curve of the load banks is obtained through experimental measurements. The experimental results are found to be in good agreement with the average model predictions. In the fully contained cold aisle system, a detailed containment CFD model is developed based on experimental measurements. The model is validated by comparing the flow rate through the perforated floor tiles and the rack inlet temperatures with the experimental measurements. The CFD results are found to be in good agreement with the experimental data with an average relative error between the measured and computed flow rate of approximately 6.7%. Temperature measurements are used to calibrate the sources of leakage in the containment and rack mounting rails. The temperature measurements and the CFD results agree well with an average difference of less than 1 °C. This study provides important modeling guidelines for data centers. In order to predict the performance of contained cold aisle systems flow distribution, it is crucial that physics based models of fan curves, server internal resistances, detailed rack models, and other design details are all accurate and experimentally verified.

Geometrical Optimization of a Venturi-Type Microbubble Generator Using CFD Simulation and Experimental Measurements

Designs ◽

10.3390/designs5010004 ◽

2021 ◽

Vol 5 (1) ◽

pp. 4

Author(s):

Dillon Alexander Wilson ◽

Kul Pun ◽

Poo Balan Ganesan ◽

Faik Hamad

Keyword(s):

Water Flow ◽

Flow Rate ◽

Cfd Simulation ◽

Air Flow ◽

Bubble Diameter ◽

Diameter Ratio ◽

Cfd Model ◽

Flow Rates ◽

Throat Diameter

Microbubble generators are of considerable importance to a range of scientific fields from use in aquaculture and engineering to medical applications. This is due to the fact the amount of sea life in the water is proportional to the amount of oxygen in it. In this paper, experimental measurements and computational Fluid Dynamics (CFD) simulation are performed for three water flow rates and three with three different air flow rates. The experimental data presented in the paper are used to validate the CFD model. Then, the CFD model is used to study the effect of diverging angle and throat length/throat diameter ratio on the size of the microbubble produced by the Venturi-type microbubble generator. The experimental results showed that increasing water flow rate and reducing the air flow rate produces smaller microbubbles. The prediction from the CFD results indicated that throat length/throat diameter ratio and diffuser divergent angle have a small effect on bubble diameter distribution and average bubble diameter for the range of the throat water velocities used in this study.

The Behaviour of Multiple Loops in Torsion

British Journal of Orthodontics ◽

10.1179/bjo.15.3.149 ◽

1988 ◽

Vol 15 (3) ◽

pp. 149-156 ◽

Cited By ~ 2

Author(s):

R. A. Cavina ◽

N. E. Waters

Keyword(s):

Energy Method ◽

Strain Energy ◽

Vertical Axis ◽

Complementary Strain ◽

Radial Axis ◽

Strain Energy Method ◽

The angular stiffness of a multiple looped span, subject to rotation about a vertical axis (torsion) and also to rotation about a horizontal or radial axis (mesio-distal tilt), have been derived using the complementary (strain) energy method. Experimental measurements on enlarged models were in good agreement with the values calculated from the theoretical relationships obtained. The variations in angular stiffness resulting from changes in the loop height, width, and position of clinical sized loops are discussed.

ELECTRONIC STRUCTURE AND OPTICAL PROPERTIES OF CRYSTALLINE C60

Modern Physics Letters B ◽

10.1142/s0217984992000399 ◽

1992 ◽

Vol 06 (06) ◽

pp. 309-321 ◽

Cited By ~ 6

Author(s):

W.Y. CHING ◽

MING-ZHU HUANG ◽

YONG-NIAN XU ◽

FANQI GAN

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

First Principles ◽

Optical Spectrum ◽

Local Density ◽

Low Dielectric Constant ◽

Absorption Bands ◽

Low Dielectric ◽

The electronic structure and optical properties of crystalline C 60 and their pressure dependence have been studied by first-principles local density calculations. It is shown that fcc C 60 has a low dielectric constant and an optical spectrum rich in structures. The spectrum shows five disconnected absorption bands in the 1.4 to 7.0 eV region with sharp structures in each band that can be attributed to critical point transitions. This is a manifestation of the localized molecular structure coupled with long range crystalline order unique to the C 60 crystal. At a sufficient high pressure, the structures in the optical spectrum start to merge due to the merging of the bands. These results are in good agreement with some recent experimental measurements.

A new look at filter backwash hydraulics

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0022 ◽

2001 ◽

Vol 1 (2) ◽

pp. 65-72 ◽

Cited By ~ 14

Author(s):

Ömer Akgiray ◽

Ahmet M. Saatçı

Keyword(s):

New Approach ◽

Ergun Equation ◽

Mathematical Formulas ◽

Good Agreement ◽

New Look

A new approach to model media expansion during filter backwash is presented. The proposed approach is based on the assumption that the Ergun equation remains valid after fluidization. Mathematical formulas are derived for predicting expanded porosity for a given backwash velocity or backwash velocity for a given expanded porosity. These formulas can be easily used by the engineer. Values predicted using the proposed approach are in good agreement with experimental measurements.

Adhesion Force Between High Energy Surfaces in Vapor Atmosphere

MRS Proceedings ◽

10.1557/proc-366-33 ◽

1994 ◽

Vol 366 ◽

Cited By ~ 4

Author(s):

Jerome Crassous ◽

Jean-Luc Loubet ◽

Elisabeth Charlaix

Keyword(s):

Liquid Bridge ◽

Adhesion Force ◽

Van Der Waals ◽

Surface Force ◽

High Energy ◽

Attractive Force ◽

Metallic Substrates ◽

Energy Surfaces ◽

ABSTRACTWe report experimental measurements of the adhesion force between metallic substrates in undersaturated heptane vapor atmosphere, with a surface force apparatus. The attractive force between the substrates is strongly dependant of the condensation of a liquid bridge connecting the surfaces. The results show the importance of wetting phenomena for the maximum attractive force: we find that this maximum attraction varies as the power two-third of the curvature of the meniscus connecting the surfaces, in good agreement with the theory of Van der Waals wetting.

Volume 3: Nuclear Safety and Security; Codes, Standards, Licensing and Regulatory Issues; Computational Fluid Dynamics and Coupled Codes ◽

Predicting Thermal Mixing and Fatigue Inside Control Rod Guide Tubes

10.1115/icone21-16632 ◽

2013 ◽

Author(s):

Eric Lillberg

Keyword(s):

Thermal Fatigue ◽

Turbulent Mixing ◽

Low Frequency ◽

Guide Tube ◽

Control Rod ◽

Thermal Mixing ◽

Purge Flow ◽

Control Rods ◽

The cracked control rods shafts found in two Swedish NPPs were subjected to thermal fatigue due to mixing of cold purge flow with hot bypass water in the upper part of the top tube on which the control rod guide tubes rests. The interaction between the jets formed at the bypass water inlets is the main source of oscillation resulting in low frequency downward motion of hot bypass water into the cold purge flow. This ultimately causes thermal fatigue in the control rod shaft in the region below the four lower bypass water inlets. The transient analyses shown in this report were done to further investigate this oscillating phenomenon and compare to experimental measurements of water temperatures inside the control rod guide tube. The simulated results show good agreement with experimental data regarding all important variables for the estimation of thermal fatigue such as peak-to-peak temperature range, frequency of oscillation and duration of the temperature peaks. The results presented in this report show that CFD using LES methodology and the open source toolbox OpenFOAM is a viable tool for predicting complex turbulent mixing flows and thermal loads.

Carbo-Nitride Precipitation in Tempered Martensite - Computer Simulation and Experiment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.706-709.1586 ◽

2012 ◽

Vol 706-709 ◽

pp. 1586-1591 ◽

Cited By ~ 5

Author(s):

Sabine Zamberger ◽

Ernst Kozeschnik

Keyword(s):

Computer Simulation ◽

Precipitation Behavior ◽

Tempered Martensite ◽

Extraction Replica ◽

Transmission Electron ◽

Simulation And Experiment ◽

Precipitate Microstructure ◽

Means Of Transmission ◽

Quenched And Tempered Steel ◽

In the present work, the precipitation behavior of a V-microalloyed, quenched and tempered steel with 0.3wt % C is investigated experimentally and by computer simulation. The specimens are analyzed by means of transmission electron microscopy using selected area diffraction (SAD) and energy dispersive x-ray spectroscopy (EDX). The analysis is done on electropolished foils and on extraction replica. The numerical simulation is performed with the thermokinetic software package MatCalc, where the precipitation kinetics is examined for the experimentally applied thermo-mechanical cycles. Good agreement between experiment and simulation is obtained and the experimentally observed precipitate microstructure can be well explained on the basis of these simulations.

Disordering of MgAl2O4 spinel from first principles

Mineralogical Magazine ◽

10.1180/002646100549210 ◽

2000 ◽

Vol 64 (2) ◽

pp. 311-317 ◽

Cited By ~ 29

Author(s):

M. C. Warren ◽

M. T. Dove ◽

S. A. T. Redfern

Keyword(s):

Free Energy ◽

Electronic Structure ◽

First Principles ◽

Large Scale ◽

Zero Temperature ◽

Macroscopic Models ◽

Tetrahedral Sites ◽

Degree Of Order ◽

AbstractAt high temperature, MgAl2O4 spinel is stabilized by disorder of Mg and Al between octahedral and tetrahedral sites. This behaviour has been measured up to 1700 K in recent neutron experiments, but the extrapolation of subsequently fitted thermodynamic models is not reliable. First principles simulation of the electronic structure of such minerals can in principle accurately predict disorder, but would require unfeasibly large computing resources. We have instead parameterized on-site and short-ranged cluster potentials using a small number of electronic structure simulations at zero temperature. These potentials were then used in large-scale statistical simulations at finite temperatures to predict disordering thermodynamics beyond the range of experimental measurements. Within the temperature range of the experiment, good agreement is obtained for the degree of order. The entropy and free energy are calculated and compared to those from macroscopic models.