THREE DIMENSIONAL (3D) OXYGEN (O2) TRANSFER MODELLING OF AN INTRAVENOUS HOLLOW FIBER GAS TRANSFER DEVICE (IH-FGTD) USING COMPUTATIONAL FLUID DYNAMICS (CFD)

New York City provides secondary treatment to approximately 78.6 m3/s among its 14 water pollution control plants (WPCPs). The process of choice has been step-feed activated sludge. Changes to the permit limits require nitrogen removal in WPCPs discharging into the Long Island Sound. The City has selected step feed biological nitrogen removal (BNR) process to upgrade the affected plants. Step feed BNR requires increasing the concentration of mixed liquors, (MLSS), which stresses the Gould II type rectangular final settling tanks (FSTs). To assess performance and evaluate alternatives to improve efficiency of the FSTs at the higher loads, New York City Department of Environmental Protection (NYCDEP) and City College of New York (CCNY) have developed a three-dimensional computer model depicting the actual structural configuration of the tanks and the current and proposed hydraulic and solids loading rates. Using Computational Fluid Dynamics (CFD) Model, Fluent 6.3.26TM as the base platform, sub-models of the SS settling characteristics as well as turbulence, flocculation, etc. were incorporated. This was supplemented by field and bench scale experiments to quantify the co-efficients integral to the sub-models. As a result, a three-dimensional model has been developed that is being used to consider different baffle arrangements, sludge withdrawal mechanisms and loading alternatives to the FSTs.

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INVESTIGATION OF FLOW BEHAVIOR AND GAS TRANSFER PERFORMANCE OF AN OXYGENATOR WITH COMPUTATIONAL FLUID DYNAMICS(CFD)

ASAIO Journal ◽

10.1097/00002480-200203000-00114 ◽

2002 ◽

Vol 48 (2) ◽

pp. 153

Author(s):

N. Katagiri ◽

A. Funakubo ◽

Y. Taenaka ◽

E. Tatsumi ◽

T. Nishinaka ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Flow Behavior ◽

Gas Transfer ◽

Transfer Performance ◽

Computational Fluid Dynamics Cfd

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A Generalized Computational Fluid Dynamics Approach for Journal Bearing Performance Prediction

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1243/pime_proc_1995_209_412_02 ◽

1995 ◽

Vol 209 (2) ◽

pp. 99-108 ◽

Cited By ~ 39

Author(s):

P G Tucker ◽

P S Keogh

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Surface Temperature ◽

Performance Prediction ◽

Reynolds Equation ◽

Three Dimensional ◽

Rotation Effect ◽

Performance Predictions ◽

Computational Fluid Dynamics Cfd ◽

Shaft Surface

The use of computational fluid dynamics (CFD) techniques enables performance predictions of bearing designs to be made when the usual operating assumptions of the Reynolds equation Jail to hold. This paper addresses the application of a full three-dimensional thermohydrodynamic CFD approach to journal bearings. The journal/shaft may extend beyond the bearing length and the rotation effect is accounted for in the thermal transport process. A circumferentially uniform shaft surface temperature is not assumed. Cavitation modelling is based on averaged lubricant/vapour properties and does not set pressures directly, allowing sub-ambient pressures to be predicted. Lubricant inlet grooves are incorporated with conservation of mass and the possibility of backflow. The modelling is validated against published experimental work on fully circumferential, single inlet and two-inlet circular bore bearings. The predicted and experimental results are in general agreement, although the predicted cyclic variation of journal surface temperature is less than the experimental value. However, an assumption in the predictions was of a non-orbiting journal. The techniques developed may, in principle, be extended to the orbiting journal case providing a dynamic cavitation model can be formulated.

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Layout Effect of Two Autonomous Underwater Vehicles on the Hydrodynamics Performances

WSEAS TRANSACTIONS ON SYSTEMS ◽

10.37394/23202.2020.19.7 ◽

2020 ◽

Vol 19 ◽

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Autonomous Underwater Vehicles ◽

Three Dimensional ◽

Pressure Change ◽

Underwater Vehicles ◽

Optimal Layout ◽

Minimum Drag ◽

Computational Fluid Dynamics Cfd ◽

Two Parameters

Three-dimensional computational fluid dynamics (CFD) is used for the design optimization of the layout of an autonomous underwater vehicles (AUV) containing three torpedo-shaped hulls. The AUV layout is defined by two parameters a and b present the stance following YY and XX respectively. several simulations are carried on the AUV with different positions of the torpedo in order to define the optimal layout which designates the minimum drag. the numerical results approve that the variation in the drag coefficient of the AUV is the to the interaction of the flow rate and the pressure change between the both hulls. in addition, an optimal layout for the minimum AUV drag with two torpedoes is found which provides a drag reduce of about 11.4% lower than a single UV with a single torpedo.

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Transient Analysis of a Spring-Loaded Pressure Safety Valve Using Computational Fluid Dynamics (CFD)

Journal of Pressure Vessel Technology ◽

10.1115/1.4001428 ◽

2010 ◽

Vol 132 (5) ◽

Cited By ~ 22

Author(s):

Xue Guan Song ◽

Lin Wang ◽

Young Chul Park

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Safety Valve ◽

Three Dimensional ◽

Pressure Vessels ◽

Moving Mesh ◽

Cfd Model ◽

Ansys Cfx ◽

Computational Fluid Dynamics Cfd ◽

Mesh Technique

A spring-loaded pressure safety valve (PSV) is a key device used to protect pressure vessels and systems. This paper developed a three-dimensional computational fluid dynamics (CFD) model in combination with a dynamics equation to study the fluid characteristics and dynamic behavior of a spring-loaded PSV. The CFD model, which includes unsteady analysis and a moving mesh technique, was developed to predict the flow field through the valve and calculate the flow force acting on the disk versus time. To overcome the limitation that the moving mesh technique in the commercial software program ANSYS CFX (Version 11.0, ANSYS, Inc., USA) cannot handle complex configurations in most applications, some novel techniques of mesh generation and modeling were used to ensure that the valve disk can move upward and downward successfully without negative mesh error. Subsequently, several constant inlet pressure loads were applied to the developed model. Response parameters, including the displacement of the disk, mass flow through the valve, and fluid force applied on the disk, were obtained and compared with the study of the behavior of the PSV under different overpressure conditions. In addition, the modeling approach could be useful for valve designers attempting to optimize spring-loaded PSVs.

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Characterization of Single-Phase Flow Hydrodynamics in Berty Reactor using Computational Fluid Dynamics (CFD)

Reaction Chemistry & Engineering ◽

10.1039/d1re00390a ◽

2021 ◽

Author(s):

Khunnawat Ountaksinkul ◽

Sirada Sripinun ◽

Panut Bumphenkiattikul ◽

Surapon Bubphacharoen ◽

Arthit Vongachariya ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Single Phase ◽

Three Dimensional ◽

Flow Characteristics ◽

Kinetic Studies ◽

Stirred Tank Reactors ◽

Computational Fluid Dynamics Cfd ◽

Continuous Stirred Tank

This work studies the flow characteristics in the Berty reactor, a gradientless reactor for kinetic studies, using three-dimensional (3D) computational fluid dynamics (CFD), and the non-ideal continuous stirred tank reactors...

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Three-Dimensional CFD Analysis of Gas Mixing in Large Volumes

10.1115/imece2001/htd-24172 ◽

2001 ◽

Author(s):

Brian L. Smith

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Steady State ◽

Three Dimensional ◽

Air Injection ◽

Cfd Analysis ◽

Gas Mixing ◽

Air Mixing ◽

Computational Fluid Dynamics Cfd ◽

Pure Steam

Abstract The paper describes three-dimensional Computational Fluid Dynamics (CFD) calculations undertaken in support of analyses of steam/air mixing which takes place in the drywell volumes of the 1/40th-scale ESBWR1 mock-up facility PANDA under conditions of symmetric steam/air injection and asymmetric outflow. Steady-state simulations for pure steam conditions illustrate how the flow streams mix to ensure balanced outflow conditions to the condensers. A transient calculation has also been performed to examine how air released from solution in the PANDA boiler would ultimately accumulate in the separate condenser units. Results provide a possible explanation for the rundown in performance of one of the condensers which was repeatedly observed in some of the PANDA tests.

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Herbst appliance effects on pharyngeal airway ventilation evaluated using computational fluid dynamics

The Angle Orthodontist ◽

10.2319/080616-603.1 ◽

2017 ◽

Vol 87 (3) ◽

pp. 397-403 ◽

Cited By ~ 10

Author(s):

Tomonori Iwasaki ◽

Hideo Sato ◽

Hokuto Suga ◽

Ayaka Minami ◽

Yuushi Yamamoto ◽

...

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Three Dimensional ◽

Control Group ◽

Herbst Appliance ◽

Oropharyngeal Airway ◽

Pharyngeal Airway ◽

Obstructive Sleep ◽

Before And After ◽

Computational Fluid Dynamics Cfd

ABSTRACT Objective: To evaluate the effect of a Herbst appliance on ventilation of the pharyngeal airway (PA) using computational fluid dynamics (CFD). Materials and Methods: Twenty-one Class II patients (10 boys; mean age, 11.7 years) who required Herbst therapy with edgewise treatment underwent cone-beam computed tomography (CBCT) before and after treatment. Nineteen Class I control patients (8 boys; mean age, 11.9 years) received edgewise treatment alone. The pressure and velocity of the PA were compared between the groups using CFD based on three-dimensional CBCT images of the PA. Results: The change in oropharyngeal airway velocity in the Herbst group (1.95 m/s) was significantly larger than that in the control group (0.67 m/s). Similarly, the decrease in laryngopharyngeal airway velocity in the Herbst group (1.37 m/s) was significantly larger than that in the control group (0.57 m/s). Conclusion: The Herbst appliance improves ventilation of the oropharyngeal and laryngopharyngeal airways. These results may provide a useful assessment of obstructive sleep apnea treatment during growth.

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