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TECHNICAL LEADERSHIP THROUGH RESEARCH
& ENGINEERING
Statistical
Methods for Evaluating Droplet Size Distribution
High-pressure water atomization nozzles produce,
by their very nature, a wide spectrum of droplet diameters.
There are two generally accepted statistical methods
used for quantifying (and qualifying) the characteristics
of inlet fogging nozzles.
Related
Links
Brochure: Gas Turbine Inlet Air Fogging. Download
PDF
White Paper: A Comparative Guide
to Inlet Air Cooling Technologies. Download
PDF
Tech Paper: GT2005-68346 PERFORMANCE
OF IMPACTION-PIN NOZZLES
The correlation's are developed from a series
of experiments conducted in a wind tunnel equipped
with the Malvern Spraytec droplet size measurement
system. Download
PDF
Cumulative Volume
Volume Frequency
This number
defines a droplet diameter for which 90% of the
mass flow of water is less than. It is helpful
when one wishes to look at the possibility of
the fog spray collecting in the inlet ducts or
impacting on compressor blades. In the above example,
less than 18 microns means that 90% of the mass
flow of water is in droplets that are 18 microns
or less.
This number
is used for defining the spray from nozzles that
are used for evaporation type processes because
evaporation time for a given droplet is a strong
function of the ratio of volume to surface area.
With the short dwell times available in a turbine
inlet duct, this is a very useful design parameter.
Issues and Conclusions:
These two statistical measurements
of droplet diameter are of primary significance for
gas turbine inlet-air cooling. As well as the location
of the measurement in the spray plume and other measurement
conditions such as airflow velocity.
Armed with the above numbers,
and assuming they represent the characteristics of
the entire water mass flow of the fog nozzles being
compared, not just a center section, a buyer can make
an informed comparison of different fogging systems.
MeeFog
Concept
HVAC