Modeling
Christopher R. Schulz, P.E., DEE
CDM Inc.
Denver, Colorado
Carrie L. Knatz, P.E. and Veronica Ortiz
CDM Inc.
Carlsbad, California
Joseph Yelpo
Sunlight Systems, Inc
Allendale, New Jersey
Introduction
Recent research has demonstrated that computational fluid dynamics and irradiance modeling
(referred to as CFD-i modeling in this paper) can be used to accurately predict the fluence (or
UV dose) in flow-through UV reactors. For example, the Metropolitan Water District of
Southern California (Mofidi, 2004) compared predicted CFD-i modeling and measured
validation testing results for a 3-mgd Calgon Sentinel reactor with four medium-pressure (MP)
lamps. The model predicted validation results within 0.1 log reduction of MS-2 coliphage.
Similarly, CFD-i modeling and biodosimetry testing results were compared for a 18-mgd
Wedeco K3000 reactor with low-pressure high-output (LPHO) lamps under various lamp power
and UVT conditions (Rokjer, 2002). The percent difference between predicted and measured
reduction equivalent dose (RED) using B. subtilis as the target organism, ranged from 5 to 20
percent for CFD-i runs at ten different flow and water quality conditions. Due to its demonstrated
accuracy, CFD-i modeling is now routinely used by UV equipment suppliers for developing new
or optimizing existing UV reactor designs. This paper presents CFD-i modeling results for a new
UV reactor design being developed by Sunlight Systems, Inc. of Allendale, New Jersey for
drinking water disinfection applications. The results were related to: optimization of the UVBox reactor design; and, a comparison of the dose delivery and hydraulic efficiency of the UVBox reactor with an unbaffled annular reactor. CFD-i modeling was used to optimize the design of the UVBox reactor with respoect to: dose delivery (RED); residence time distribution (RTD); hydrodynamic flow patterns in the reactor; and, pressure drop across the reactor. Three UV reactor configurations were analyzed using CFD-i modeling: UVBox unbaffled reactor with 30-inch inlet/outlet flanges, rectangular vessel dimensions of
30 inches wide by 30 inches high by 30 inches long and four MP lamps positioned
perpendicular to flow;
UVBox baffled reactor with the same vessel dimensions and lamp configuration as above, plus
six angled flow deflector baffles positioned upstream and downstream of the lamps to direct
the flow closer to the lamp sleeves and introduce flow recirculation patterns between the upstream and downstream baffles; and,
annular unbaffled reactor with 30 inch inlet/outlet flanges and tubular vessel dimensions of 30 inch inlet/outlet flanges and tubular vessel dimensions of 30 inches long by 30 inches in diameter.
Includes 7 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.3 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 11/15/2004 |
