scholarly journals Inerting Strategy for a Demonstration-Scale Hot Cell Facility Based on Experiences from Pilot-Scale Argon Cell Facility Operation and CFD Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Seungnam Yu ◽  
Jaehoon Lim ◽  
Ilje Cho ◽  
Jonghui Han
Keyword(s):  
Flow Rate ◽  
Cfd Simulation ◽  
Scale Up ◽  
Pilot Scale ◽  
Process Equipment ◽  
Successful Operation ◽  
Study Results ◽  
Computational Fluid Dynamics Cfd ◽  
Gas Tight ◽  
Practical Constraints

Pyroprocessing is being developed at Korea Atomic Energy Research Institute (KAERI), and in recent years, all process equipment required for integrated processes have been examined in the PyRoprocess-integrated Inactive DEmonstration (PRIDE) facility. Based on the successful operation of a pilot-scale facility, a conceptual design for this scale-up facility was actualized. Implementing a “demonstration-scale” hot cell facility is challenging as it is intended to supersede PRIDE and satisfy the increased requirements of larger-scale facilities. This study focused on an inerting strategy for a larger-scale (demonstration-scale) hot cell facility to achieve conditions equivalent to those in a pilot-scale gas-tight argon cell facility. The study applies the inerting strategy to a demonstration-scale hot cell facility beyond that of the currently existing pilot-scale hot cell facility and performs computational fluid dynamics (CFD) simulation with various flow rates to determine an appropriate approach for inerting the target facility. To this end, practical constraints on the simulation are introduced based on experiences from the existing pilot-scale facility. The results show that the purging flow rate should be accurately predicted, and a variable flow rate should be applied to achieve hot cell inerting effectively. The required purging time and amount of inerting source are essential factors in the larger-scale hot cell facility. The study results can be helpful in the design of large hot cell facilities operated under inert conditions.

Numerical Investigation on Ventilation Strategy for Laboratories: An Approach to Control Thermal Comfort and Air Quality Using Active Chilled Beams

2007 ◽  
Author(s):  
Farhad Memarzadeh ◽  
Jane Jiang ◽  
Andy Manning
Keyword(s):  
Air Quality ◽  
Thermal Comfort ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Washington Dc ◽  
Ventilation Strategy ◽  
Flow Rates ◽  
Beam System ◽  
Computational Fluid Dynamics Cfd ◽  
Lower Flow Rate

Laboratories are usually equipment intensive. The supply flow rates required to cool these laboratories are generally higher than in a less equipment intensive zone of the building. The thermal comfort of occupants in laboratories can be controlled by the choice of ventilation strategy. This study employs Computational Fluid Dynamics (CFD) simulation to assess the performance of active chilled beams in a general laboratory layout with some equipment intensive areas and the removal effectiveness of such a system. The chilled beam performance is also compared with at of ceiling diffusers. The results from this study show that the chilled beams improve thermal comfort, and they can be operated at as low as 4 ACH while maintaining very satisfactory average PPD (around 10%) in the occupied zones. The chilled beam system also improves removal effectiveness because of the inherent higher total supply flow rate that results in a better mixing in the room than ceiling diffusers. The chilled beams in the cases studied are seen to have an insignificant effect on the hood containment. As satisfactory thermal comfort and air quality can be achieved at a lower flow rate in comparison with all-air ceiling diffusers, a 14% saving is estimated in annual energy cost for cooling and ventilating a typical lab in the Washington DC area.

Scale-up and biomass hold-up characteristics of biological fluidized bed reactors

1994 ◽  
Vol 29 (10-11) ◽  
pp. 353-360 ◽  
Author(s):  
I. Ozturk ◽  
M. Turan ◽  
A. H. Idris
Keyword(s):  
Fluidized Bed ◽  
Scale Up ◽  
Experimental Studies ◽  
Scaling Up ◽  
Pilot Scale ◽  
Fluidized Bed Reactors ◽  
Biofilm Thickness ◽  
Study Results ◽  
Scaling Down ◽  
Comprehensive Study

This paper presents a comprehensive study results on scale-up and biomass hold-up characteristics of biological fluidized bed reactors (BFBR). The overall objective of this study was to establish and test some basic design criteria for the scaling-up or scaling-down of anaerobic fluidized bed reactors. A 12.5 1 laboratory-scale fluidized bed was designed and constructed based on a geometrically similar 70 1 pilot scale fluidized bed and the process performances were compared. Biomass hold up characteristics of the BFBRs were also investigated during the experimental studies. A general expression was developed for predicting the biological fludized bed porosities. Using this expression, both the local and overall fluidized bed porosities could be predicted depending on biofilm thickness, expansion coefficient, media diameter and density. The validity of this expression was tested with the data from this study.

scholarly journals Assessment of Different Pressure Drop-Flow Rate Equations in a Pressurized Porous Media Filter for Irrigation Systems

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2179
Author(s):  
Jonathan Graciano-Uribe ◽  
Toni Pujol ◽  
Jaume Puig-Bargués ◽  
Miquel Duran-Ros ◽  
Gerard Arbat ◽  
...  
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Silica Sand ◽  
Rate Equations ◽  
Uncertainty Range ◽  
Head Losses ◽  
Computational Fluid Dynamics Cfd ◽  
Drop Flow

The small open area available at the slots of underdrains in pressurized granular bed filters for drip irrigation implies: (1) the existence of a region with non-uniform flow, and (2) local values of modified particle Reynolds number >500. These flow conditions may disagree with those accepted as valid for common pressure drop-flow rate correlations proposed for packed beds. Here, we carried out detailed computational fluid dynamics (CFD) simulations of a laboratory filter to analyze the results obtained with five different equations of head losses in porous media: (1) Ergun, (2) Darcy-Forchheimer, (3) Darcy, (4) Kozeny-Carman and (5) power function. Simulations were compared with experimental data at different superficial velocities obtained from previous studies. Results for two silica sand media indicated that all equations predicted total filter pressure drop values within the experimental uncertainty range when superficial velocities <38.3 m h−1. At higher flow rates, Ergun equation approximated the best to the observed results for silica sand media, being the expression recommended. A simple analytical model of the pressure drop along flow streamlines that matched CFD simulation results was developed.

scholarly journals CFD Simulation of Airflow Dynamics During Cough Based on CT-Scanned Respiratory Airway Geometries

Symmetry ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 595 ◽  
Author(s):  
Guiyue Kou ◽  
Xinghu Li ◽  
Yan Wang ◽  
Mouyou Lin ◽  
Yuping Zeng ◽  
...  
Keyword(s):  
Flow Rate ◽  
Cfd Simulation ◽  
Peak Flow ◽  
Maximum Velocity ◽  
Flow Distribution ◽  
Peak Flow Rate ◽  
Respiratory Airway ◽  
Computational Fluid Dynamics Cfd ◽  
Left And Right ◽  
Cfd Method

The airflow dynamics observed during a cough process in a CT-scanned respiratory airway model were numerically analyzed using the computational fluid dynamics (CFD) method. The model and methodology were validated by a comparison with published experimental results. The influence of the cough peak flow rate on airflow dynamics and flow distribution was studied. The maximum velocity, wall pressure, and wall shear stress increased linearly as the cough peak flow increased. However, the cough peak flow rate had little influence on the flow distribution of the left and right main bronchi during the cough process. This article focuses on the mathematical and numerical modelling for human cough process in bioengineering.

Experimental Study of Down Hole Gas Liquid Separators

2009 ◽  
Author(s):  
Zunce Wang ◽  
Sen Li ◽  
Fengxia Lv ◽  
Yan Xu ◽  
Jinlong Zhang
Keyword(s):  
Flow Rate ◽  
Cfd Simulation ◽  
Structural Parameters ◽  
Cone Angle ◽  
Field Tests ◽  
Operating Parameters ◽  
Separation Performance ◽  
Liquid Ratio ◽  
Gas Well ◽  
Computational Fluid Dynamics Cfd

The technology of Down-hole Gas Liquid Separation and Water Re-injection (DGLSWR) is an economical and effective method to solve gas well fluid accumulation. The separation performance of designed Down-hole Gas Liquid Separator (DGLS) is very important for DGLSWR systems applications. The principle of work and Characteristics of DGLSWR systems are introduced in this paper. Separation performance of DGLS was studied using computational fluid dynamics (CFD) simulation combining laboratory experiment. Relations of main operating parameters, such as flow rate and gas liquid ratio with pressure drop were studied. The effect of flow rate, gas liquid ratio and main structural parameters such as cone angle and exhaust on DGLS separation performance was also studied. Appropriate structure and operating parameters were determined. Field tests indicated satisfactory results as well.

scholarly journals Comparison of Experimental Results to CFD Models for Blending in a Tank Using Dual Opposing Jets

2011 ◽  
Author(s):  
Robert A. Leishear ◽  
Si Y. Lee ◽  
Mark D. Fowley ◽  
Michael R. Poirier ◽  
Timothy J. Steeper
Keyword(s):  
Liquid Radioactive Waste ◽  
Scale Up ◽  
Pilot Scale ◽  
Full Scale ◽  
Experimental Results ◽  
Cfd Models ◽  
Waste Storage ◽  
Scale Models ◽  
Computational Fluid Dynamics Cfd ◽  
Cooling Coils

Research has been completed in a pilot scale, eight foot diameter tank to investigate blending, using a pump with dual opposing jets. The jets re-circulate fluids in the tank to promote blending when fluids are added to the tank. Different jet diameters and different horizontal and vertical orientations of the jets were investigated. In all, eighty five tests were performed both in a tank without internal obstructions and a tank with vertical obstructions similar to a tube bank in a heat exchanger. These obstructions provided scale models of several miles of two inch diameter, serpentine, vertical cooling coils below the liquid surface for a full scale, 1.3 million gallon, liquid radioactive waste storage tank. Two types of tests were performed. One type of test used a tracer fluid, which was homogeneously blended into solution. Data were statistically evaluated to determine blending times for solutions of different density and viscosity, and the blending times were successfully compared to computational fluid dynamics (CFD) models. The other type of test blended solutions of different viscosity. For example, in one test a half tank of water was added to a half tank of a more viscous, concentrated salt solution. In this case, the fluid mechanics of the blending process was noted to significantly change due to stratification of fluids. CFD models for stratification were not investigated. This paper is the fourth in a series of papers resulting from this research (Leishear, et.al. [1–4]), and this paper documents final test results, statistical analysis of the data, a comparison of experimental results to CFD models, and scale-up of the results to a full scale tank.

Optimization of Quench Tank Structure Based on CFD Simulation

2006 ◽  
Vol 118 ◽  
pp. 363-368 ◽  
Author(s):  
Nai Lu Chen ◽  
Wei Min Zhang ◽  
Qiang Li ◽  
Chang Yin Gao ◽  
Bo Liao ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Draft Tube ◽  
Structure Design ◽  
Rate Distribution ◽  
Large Size ◽  
Solid Foundation ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

In order to investigate the flow rate distribution and improve the flow rate uniformity of the quenchant in a quench tank, the ultrasonic Doppler velocimeter (UDV) was used to measure the flow rate of quenchant with agitation, and then a computational fluid dynamics (CFD) simulation was carried out to simulate the flow rate distribution without / with flow baffles. According to the CFD simulation results, the structures and positions of flow baffles in the draft-tube were optimized to obtain the uniform flow rate distribution in the quench zone, which were verified by experiments as well. The simulation and experimental results show that the UDV is suitable for measuring the flow rate of a large-size quench tank. This research provided a solid foundation for optimizing the structure design of flow baffles in production quench tanks.

scholarly journals Theoretical and Practical Issues That Are Relevant When Scaling Up hMSC Microcarrier Production Processes

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Valentin Jossen ◽  
Cedric Schirmer ◽  
Dolman Mostafa Sindi ◽  
Regine Eibl ◽  
Matthias Kraume ◽  
...  
Keyword(s):  
Stem Cells ◽  
Scale Up ◽  
Human Mesenchymal Stem Cells ◽  
Scaling Up ◽  
Pilot Scale ◽  
Culture Broth ◽  
Cell Therapies ◽  
Computational Fluid Dynamics Cfd ◽  
Cell Densities ◽  
Stirred Bioreactors

The potential of human mesenchymal stem cells (hMSCs) for allogeneic cell therapies has created a large amount of interest. However, this presupposes the availability of efficient scale-up procedures. Promising results have been reported for stirred bioreactors that operate with microcarriers. Recent publications focusing on microcarrier-based stirred bioreactors have demonstrated the successful use of Computational Fluid Dynamics (CFD) and suspension criteria (NS1u,NS1) for rapidly scaling up hMSC expansions from mL- to pilot scale. Nevertheless, one obstacle may be the formation of large microcarrier-cell-aggregates, which may result in mass transfer limitations and inhomogeneous distributions of stem cells in the culture broth. The dependence of microcarrier-cell-aggregate formation on impeller speed and shear stress levels was investigated for human adipose derived stromal/stem cells (hASCs) at the spinner scale by recording the Sauter mean diameter (d32) versus time. Cultivation at the suspension criteria providedd32values between 0.2 and 0.7 mm, the highest cell densities (1.25 × 106cells mL−1hASCs), and the highest expansion factors (117.0 ± 4.7 on day 7), while maintaining the expression of specific surface markers. Furthermore, suitability of the suspension criterionNS1uwas investigated for scaling up microcarrier-based processes in wave-mixed bioreactors for the first time.

scholarly journals Computational Simulations of the 4-D Micro-Circulatory Network in Zebrafish Tail Amputation and Regeneration

2021 ◽  
Author(s):  
Mehrdad Roustaei ◽  
Kyung In Baek ◽  
Zhaoqiang Wang ◽  
Susana Cavallero ◽  
Sandro Satta ◽  
...  
Keyword(s):  
Flow Rate ◽  
Cfd Simulation ◽  
Fluorescent Protein ◽  
Cfd Modeling ◽  
Endothelial Lining ◽  
Zebrafish Model ◽  
Cardinal Vein ◽  
Vascular Regeneration ◽  
Computational Fluid Dynamics Cfd ◽  
Green Fluorescent

AbstractWall shear stress (WSS) in the micro-vasculature contributes to biomechanical cues that regulate mechanotransduction underlying vascular development, regeneration, and homeostasis. We hereby elucidate the interplay between hemodynamic shear forces and luminal remodeling in response to vascular injury and regeneration in the zebrafish model of tail amputation. Using the transgenic Tg(fli1:eGFP; Gata1:ds-red) line, we were able to track the enhanced green-fluorescent protein (eGFP)-labeled endothelial lining of the 3-D microvasculature for post-image segmentation and reconstruction of fluid domain for computational fluid dynamics (CFD) simulation. At 1 day post amputation (dpa), dorsal aorta (DA) and posterior cardinal vein (PCV) were severed, and vasoconstriction developed in the dorsal longitudinal anastomotic vessel (DLAV) with a concomitant increase in WSS in the segmental vessels (SV) proximal to the amputation site and a decrease in WSS in SVs distal to amputation. Simultaneously, we observed angiogenesis commencing at the tips of the amputated DLAV and PCV where WSS was minimal in the absence of blood flow. At 2 dpa, vasodilation occurred in a pair of SVs proximal to amputation, resulting in increased flow rate and WSS, whereas in the SVs distal to amputation, WSS normalized to the baseline. At 3 dpa, the flow rate in the arterial SV proximal to amputation continued to rise and merged with DLAV that formed a new loop with PCV. Thus, our CFD modeling uncovered a well-coordinated micro-vascular adaptation process following tail amputation, accompanied by the rise and fall of WSS and dynamic changes in flow rate during vascular regeneration.

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