The output and efficiency of gas turbines are reduced significantly during the summer, especially in areas where the daytime temperature reaches as high as 50°C. Gas turbine inlet fogging and overspray has been considered a simple and cost-effective method to increase the power output. One of the most important issues related to inlet fogging is to determine the most effective location of the fogging device by determining (a) how many water droplets actually evaporate effectively to cool down the inlet air instead of colliding on the wall or coalescing and draining out (i.e., fogging efficiency), and (b) quantifying the amount of nonevaporated droplets that may reach the compressor bellmouth to ascertain the erosion risk for compressor airfoils if wet compression is to be avoided. When the silencer is installed, there is an additional consideration for placing the fogging device upstream or downstream of the silencer baffles. Placing arbitrarily the device upstream of the silencer can cause the silencer to intercept water droplets on the silencer baffles and lose cooling effectiveness. This paper employs computational fluid dynamics (CFD) to investigate the water droplet transport and cooling effectiveness with different spray locations such as before and after the silencer baffles. Analysis on the droplet history (trajectory and size) is employed to interpret the mechanism of droplet dynamics under influence of acceleration, diffusion, and body forces when the flow passes through the baffles and duct bent. The results show that, for the configuration of the investigated duct, installing the fogging system upstream of the silencer is about 3 percentage points better in evaporation effectiveness than placing it downstream of the silencer, irrespective of whether the silencer consists of a single row of baffles or two rows of staggered baffles. The evaporation effectiveness of the staggered silencer is about 0.8 percentage points higher than the single silencer. The pressure drop of the staggered silencer is 6.5% higher than the single silencer.

References

References
1.
Cortes
,
C. R.
, and
Willems
,
D. E.
, 2003, “
Gas Turbine Inlet Air Cooling Techniques: An Overview of Current Technologies
,” POWER-GEN, Las Vegas, Nevada, USA.
2.
Angello
,
L.
, 2005, “
Axial Compressor Performance Maintenance Guide Update
,” EPRI Technical Update, Document no. 1008325.
3.
Acoustical Surfaces Inc.
, “
Silent-Mod Duct Silencer
,” 2010, http://www.acousticalsurfaces.comhttp://www.acousticalsurfaces.com
4.
American Air Filter
, “
Rectangular Duct Mute
,” 2010, http://www.aafintl.comhttp://www.aafintl.com
5.
UNCER Technologies Inc.
, “
UNCER Silencer
,” 2010, http://www.enoisecontrol.comhttp://www.enoisecontrol.com
6.
Industrial Acoustics Company
, “
IAC Silencer
,” 2010, http://www.soundcontrol4less.comhttp://www.soundcontrol4less.com
7.
Chaker
,
M.
,
Meher-Homji
,
C. B.
, and
Mee
,
T. R.
, 2004, “
Inlet Fogging of Gas Turbine Engines—Part I: Fog Droplet Thermodynamics, Heat Transfer, and Practical Considerations
,”
ASME J. Eng. Gas Turbines Power
,
126
, pp.
545
558
.
8.
Chaker
,
M.
,
Meher-Homji
,
C. B.
, and
Mee
,
T. R.
, 2004, “
Inlet Fogging of Gas Turbine Engines—Part II: Fog Droplet Sizing Analysis, Nozzle Types, Measurement, and Testing
,”
ASME J. Eng. Gas Turbines Power
,
126
, pp.
559
570
.
9.
Chaker
,
M.
,
Meher-Homji
,
C. B.
, and
Mee
,
T. R.
, 2004, “
Inlet Fogging of Gas Turbine Engines—Part III: Fog Behavior in Inlet Ducts, Computational Fluid Dynamics Analysis, and Wind Tunnel Experiments
,”
ASME J. Eng. Gas Turbines Power
,
126
, pp.
571
580
.
10.
Li
,
X.
, and
Wang
,
T.
, 2007, “
Effects of Various Modelings on Mist Film Cooling
,”
ASME J. Heat Transfer
,
129
, pp.
472
482
.
11.
Wang
,
T.
, and
Dhanasekaran
,
T. S.
, 2010, “
Calibration of CFD Model for Mist/Steam Impinging Jets Cooling
,”
ASME J. Heat Transfer
,
132
(
12
), p.
122201
.
12.
Wang
,
S.
,
Liu
,
G.
,
Mao
,
J.
, and
Feng
,
Z.
, 2007, “
Experimental Investigation on the Solid Particle Erosion in the Control Stage Nozzles of Steam Turbine
,” ASME Paper No. GT2007-27700.
13.
Schiller
,
L.
, and
Naumann
,
A.
, 1933, “
Uber die grundlegenden Berechnungen bei der Schwekraftaubereitung
,”
Z. Ver. Dtsch. Ing.
,
77
(
12
), pp.
318
320
.
14.
Ranz
,
W. E.
, and
Marshall
,
W. R.
, Jr.
, 1952, “
Evaporation from Drops, Part I
,”
Chem. Eng. Prog.
,
48
, pp.
141
146
.
15.
Ranz
,
W. E.
, and
Marshall
,
W. R.
, Jr.
, 1952, “
Evaporation from Drops, Part II
,”
Chem. Eng. Prog.
,
48
, pp.
173
180
.
16.
Kuo
,
K. Y.
, 1986,
Principles of Combustion
,
John Wiley and Sons
,
New York
.
17.
Watchers
,
L. H. J.
, and
Westerling
,
N. A.
, 1966, “
The Heat Transfer from a Hot Wall to Impinging Water Drops in the Spherioidal State
,”
Chem. Eng. Sci.
,
21
, pp.
1047
1056
.
18.
Harlow
,
F. H.
, and
Shannon
,
J. P.
, 1967, “
The Splash of a Liquid Drop
,”
J. Appl. Phys.
,
38
, pp.
3855
3866
.
19.
Bai
,
C.
, and
Gosman
,
A. D.
, 1995, “
Development of Methodology for Spray Impingement Simulation
,” SAE Paper No. 950283.
20.
Stanton
,
D. W.
, and
Rutland
,
C. J.
, 1996, “
Modeling Fuel Film Formation and Wall Interaction in Diesel Engines
,” SAE Paper No. 960628.
21.
Rourke
,
P. J. O.
, and
Amsden
,
A. A.
, 2000, “
A Spray/Wall Interaction Submodel for the KIVA-3 Wall Film Model
,” SAE Paper No. 2000-01-0271.
22.
Dhanasekaran
,
T. S.
, and
Wang
,
T.
, 2010, “
Model Verification of Mist/Steam Cooling with Jet Impingement Onto a Concave Surface and Prediction at Elevated Operating Condition
,” ASME Paper No. GT2010-22238.
23.
Fluent, Inc., 2008, FLUENT Manual, Version 6.3, Ansys Inc., Canonsburg, PA.
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