Development and Validation of a 3-Dimensional Computational Fluid Dynamics (CFD) Model for Rectangular Settling Tanks in New York City Water Pollution Control Plants

2009 ◽  
Vol 4 (1) ◽  
Author(s):  
K. Ramalingam ◽  
J. Fillos ◽  
S. Xanthos ◽  
M. Gong ◽  
A. Deur ◽  
...  
Keyword(s):  
Water Pollution ◽  
Fluid Dynamics ◽  
New York ◽  
Computational Fluid Dynamics ◽  
New York City ◽  
Pollution Control ◽  
York City ◽  
Three Dimensional ◽  
Cfd Model ◽  
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.

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

2010 ◽  
Vol 132 (5) ◽  
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.

FULL-SCALE EVALUATION OF STEP-FEED BNR PROCESS AT A NEW YORK CITY WATER POLLUTION CONTROL PLANT

2002 ◽  
Vol 2002 (11) ◽  
pp. 100-109 ◽  
Author(s):  
J. Fillos ◽  
K. Ramalingam ◽  
S. Thomatos ◽  
L.A. Carrio ◽  
K. Gopalakrishnan ◽  
...  
Keyword(s):  
Water Pollution ◽  
New York ◽  
New York City ◽  
Pollution Control ◽  
York City ◽  
Control Plant ◽  
Full Scale ◽  
Scale Evaluation ◽  
Water Pollution Control ◽  
City Water

Investigation of the Effect of Fuel Reactivity on Dual-Fuel PCI Combustion

2012 ◽  
Vol 588-589 ◽  
pp. 287-290
Author(s):  
Li Jun Ou ◽  
Chun Mei Wang ◽  
Hui Chun Wang ◽  
Su Wei Zhu ◽  
Ye Jian Qian
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Exhaust Emissions ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Cfd Model ◽  
Ignition Timing ◽  
Computational Fluid Dynamics Cfd

The potential of controlling premixed compression ignition (PCI) combustion by two fuels with different ignitability and volatility was studied numerically by a three-dimensional computational fluid dynamics (CFD) model. The results indicate that the addition of gasoline to diesel fueled PCI engine can retard the ignition timing, lower the in-cylinder temperature, and reduce the exhaust emissions.

Sign in / Sign up

Export Citation Format

Share Document