ASTM E1620-97(2012)

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Designation: E1620 − 97(Reapproved 2012)
Standard Terminology
Relating to Liquid Particles and Atomization
This standard is issued under the fixed designation E1620; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
The transformation of bulk liquid into collections of discrete drops in sprays or mists is required for
many processes including combustion, spray drying, evaporative cooling, humidification, and spray
coating. Several techniques are commonly used to measure and characterize collections of drops as
found in sprays, and a substantial body of terminology has evolved to describe liquid drops, drop
populations, sprays, and spray devices, all of which are of interest to the users of liquid atomizers,
spray instruments, and data. This terminology lists terms commonly encountered in the literature on
liquid drops and sprays and provides definitions specific to the subject area.
1. Scope 1.3.4 Terms pertaining to statistical parameters involving
particle measurement, particle size, and size distribution func-
1.1 In a broad sense, this terminology covers terminology
tions.
associated with liquid particles dispersed in gas. The principal
1.3.5 Terms pertaining to instruments and test procedures
emphasis, however, is on particles produced by the process of
utilized in the characterization of liquid particles and sprays.
atomization.
1.4 The values stated in SI units are to be regarded as
1.2 All terms, followed by their definitions, are arranged
standard. No other units of measurement are included in this
alphabetically. In addition, the terminology contains several
standard.
tables wherein terms related to specific subjects are segregated
and identified.
2. Referenced Documents
1.3 Within the broad scope, the following specific catego-
2.1 ASTM Standards:
ries are included:
D1356 Terminology Relating to Sampling and Analysis of
1.3.1 Terms pertaining to the structure and condition of
Atmospheres
individualparticlesorgroupsofparticlesasobservedinnature.
E799 Practice for Determining Data Criteria and Processing
1.3.2 Terms pertaining to the structure and condition of
for Liquid Drop Size Analysis
individual particles or groups of particles produced by an
atomizing device.
3. Terminology
1.3.3 Terms pertaining to atomizing devices according to
the primary energy source responsible for spray development.
aerating nozzle, n—a device to atomize liquid for the purpose
(When more than one term is used for the same device or class
of aeration.
of devices, the alternative term is followed by the preferred DISCUSSION—Although this term is occasionally used to designate
certain types of airblast or internal mixing pneumatic atomizers, it is
term.) Definitions of the devices may refer to their
ambiguous and is not recommended for describing the latter devices.
construction, operating principle, or distinctive spray charac-
teristics. The atomizers, however, are not classified by their
aerodynamic diameter, n—the diameter of a hypothetical
respective areas of application or end use. Moreover, the listed
sphere having a specific gravity of unity and the same
terms are generic and do not include brand names, trademarks,
settling velocity as the actual particle.
or proprietary designations.
aerosol, n—a dispersion of solid particles or liquid particles, or
both, in gaseous media. D1356
This terminology is under the jurisdiction ofASTM Committee E29 on Particle
and Spray Characterization and is the direct responsibility of Subcommittee E29.02
on Non-Sieving Methods. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved April 1, 2012. Published May 2012. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1994. Last previous edition approved in 2004 as E1620 – 97 (2004). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/E1620-97R12. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1620 − 97 (2012)
TABLE 1 Summary of Atomizer Terms
Pressure Atomizer (hydraulic atomizer, pressure atomizing nozzle, Lubbock nozzle
pressure nozzle, single-fluid atomizer) variable orifice poppet nozzle (variable orifice pintle nozzle)
cone atomizer (cone spray nozzle)
hollow cone atomizer Pneumatic Atomizer (air atomizing nozzle, blast nozzle, gas atomizer, gas-
solid cone atomizer (full cone nozzle) liquid nozzle, twin-fluid atomizer, two-fluid atomizer)
deflector atomizer (flood nozzle, flooding nozzle) air assist nozzle
dual orifice nozzle (duple nozzle) airblast nozzle (air blast nozzle,
duplex nozzle aerating nozzle)
piloted airblast nozzle (simplex airblast nozzle)
Fan Spray Atomizer: prefilming airblast nozzle
even spray atomizer (even flow atomizer)
flat spray atomizer (flat jet atomizer) External Mixing Pneumatic Atomizer
Laskin nozzle
Fog Nozzle
Internal Mixing Pneumatic Atomizer
Impact Atomizer: (impingement atomizer): (aerating nozzle,
pintle atomizer Nukiyama-Tanasawa nozzle,
splash cup atomizer effervescent atomizer)
splash plate atomizer
Centrifugal Atomizer (rotary atomizer, slinger)
Impinging Jet Atomizer (impingement atomizer): rotary cup atomizer (spinning cup atomizer)
doublet atomizer rotary disk atomizer (spinning disk atomizer)
triplet atomizer rotary wheel atomizer
Plain Jet Atomizer (orifice atomizer, plain orifice atomizer, single jet atomizer, Vibratory Atomizer (vibrative atomizer)
straight stream nozzle) electromagnetic vibratory atomizer
simplex nozzle piezoelectric vibratory atomizer
Square Spray Nozzle Berglund-Liu atomizer
sonic nozzle
Swirl Atomizer ultrasonic nozzle
Swirl Chamber Atomizer (centrifugal pressure nozzle, swirl chamber vibrating needle atomizer
atomizer) vibrating reed atomizer
by-pass nozzle (bypass nozzle, flowback nozzle, recirculating nozzle, return
flow nozzle, spill nozzle, spill return nozzle, spillback nozzle) Electrostatic Atomizer
dual orifice nozzle (duplex nozzle)
duplex nozzle Shear Coaxial Injector
simplex nozzle swirl coaxial injector
variable-area nozzle
Siphon Nozzle (aspirating nozzle)
Sonic Nozzle (sonic-whistle atomizer, ultrasonic nozzle)
TABLE 2 Characteristic Particle Diameters and Distribution
air atomizing nozzle, n—see pneumatic atomizer.
Functions
air blast nozzle, n—see airblast nozzle.
Aerodynamic Diameter
airblast nozzle, n—a pneumatic atomizer that utilizes a rela-
Area (surface) Mean Diameter
tively large volume of low-pressure air.
D D D D
Nf, Lf, Af, Vf
DISCUSSION—The term is occasionally used to designate the entire
De Brouckere Diameter
Equivalent Volume Sphere class of pneumatic atomizers.
Diameter
aspirating nozzle, n—see siphon nozzle.
Evaporative Diameter
Herdan Diameter
atomization, n—the process of atomizing.
Linear (arithmetic) Mean Diameter
Log Normal Distribution
atomize, v—to transform bulk liquid or slurry into particles.
Mean Diameters
Normal Distribution atomizer, n—a device for atomizing.
Nukiyama-Tanasawa Distribution
Relative Span Berglund-Liu atomizer, n—a vibratory atomizer in which a
Rosin-Rammler Distribution
piezoelectric transducer transmits high-frequency oscilla-
Sauter Mean Diameter
tions to a liquid stream discharged through an orifice,
Square Root Normal Distribution
creating relatively uniform drops whose size is a function of
Stokes’ Diameter
Upper Limit Log Normal
the frequency of oscillation and the flow rate of the liquid
Distribution
through the orifice.
Volume Mean Diameter
blast nozzle, n—see pneumatic atomizer.
breakup, n—liquid disintegration that occurs during atomiza-
tion.
air assist nozzle, n—a pneumatic atomizer in which pressur-
ized air is utilized to enhance the atomization produced by breakup length, n—the distance between the liquid discharge
pressurized liquid. The air may be required only for part of point of an atomizing device and the point where liquid
the operating range (for example, low liquid flow rates). breakup commences.
E1620 − 97 (2012)
DISCUSSION—For sprays whose drop size distributions are axisym-
bypass nozzle, n—see by-pass nozzle.
metric in space, anAbel inversion procedure has been used to perform
by-pass nozzle, n—a swirl chamber atomizer containing by-
3,4
the deconvolution.
pass orifice(s) or port(s) through which part of the inlet
liquid may be withdrawn from the swirl chamber and deflector atomizer, n—an atomizer in which a liquid jet
returned to the supply tank or pressure pump suction. The spreads out over a solid surface, forming a spray whose
discharge flow is modulated by controlling the pressure in shape depends upon the solid surface.
the bypass line, using a valve in the line.
dispersion, n—a system of particles distributed in a solid,
liquid, or gas.
cavitation, n—the formation of vapor-filled cavities in the
interiororonthesolidboundariesofliquidsinmotionwhere
dispersion, n—the spread of values of a frequency distribution
thepressureisreducedtoacriticalvaluewithoutachangein
about an average (in statistics). (Quantitative measures of
ambient temperature.
dispersion include range, variance, standard deviation, mean
deviation, and relative span.)
centrifugal atomizer, n—a device wherein a rotating solid
surface is the primary source of energy utilized to produce a
doublet injector, n—an impinging jet atomizer in which there
spray.
are two colliding liquid jets.
DISCUSSION—Alternatively, an atomizer that rotates to distribute the
drop, n—a single liquid particle having a generally spheroidal
liquid.
shape.
centrifugal pressure nozzle, n—see swirl chamber atomizer.
droplet, n—see drop; also a small drop.
circumferential patternation, n—measurements taken in a
dual orifice nozzle, n—a swirl chamber atomizer containing a
circumferential direction, showing the variation in liquid
primaryinjectorandaconcentricannularsecondaryinjector,
flux about the nozzle axis.
each injector comprising a separate orifice and set of
tangential slots. The nozzle is normally operated only with
cloud, n—any collection of particulate matter in the atmo-
the primary injector at low flow rates, with secondary liquid
sphere dense enough to be perceptible to the eye, especially
introduced at a specified pressure. (This definition applies to
a collection of water drops. D1356
devices used in the gas turbine industry.)
coalescence, n—the merging of two or more liquid particles to
duple nozzle, n—see dual orifice nozzle.
form a single liquid particle.
duplex nozzle, n—a swirl chamber atomizer comprising a
concentration, n—see number density.
single discharge orifice and two sets of tangential slots, each
cone atomizer, n—an atomizer that produces a conical spray with a separately controlled liquid supply. The smaller
(primary) slots supply liquid at low flow rates, and both sets
pattern.
(primary and secondary) are utilized as flow increases.
cone pattern, n—a diverging spray pattern that is nominally
effervescent atomizer, n—an internal mixing pneumatic atom-
symmetric about the nozzle axis and whose apex is located
izer in which gas bubbles are dispersed in the liquid stream.
at or near the nozzle discharge orifice.
electromagnetic vibratory atomizer, n—a vibratory atomizer
cone spray nozzle, n—see cone atomizer.
in which an electromagnetic transducer transmits high-
convolution, n—the combination of local measurements of
frequency oscillations to the liquid.
drop size distribution and number density into equivalent
line-of-sight values of drop size distribution and optical electrostatic atomizer, n—a device wherein an electric charge
extinction. is the primary source of energy utilized to produce a spray.
emitting spray angle, n—see initial spray angle.
D ,D ,D ,D , n—diameters such that the cumulative
Nf Lf Af Vf
number of particles, (N), length of diameter, (L), surface
equivalent volume sphere diameter, n—the diameter of a
area, (A), or volume, (V), from zero diameter to these
hypothetical sphere having the same volume as the actual
respective diameters is the fraction, (f), of the corresponding
particle.
sum for the total distribution.
even flow atomizer, n—see even spray atomizer.
Example—D is the volume median diameter; that is,
V0.5
50 % of the total volume of liquid is in drops of smaller
diameter and 50 % is in drops of larger diameter. Hammond, D.C., “A Deconvolution Technique for Line-Of-Sight Optical
Scattering Measurements in Axisymmetric Sprays,” Applied Optics, Vol 20, No. 3,
February 1981, pp. 493–499.
deconvolution, n—a procedure by which line-of-sight mea-
Yule, A.J., Ah Seng, C., Felton, P.G., Ungut, A., and Chigier, N.A., “A Laser
surements of drop size distribution and optical extinction are
Tomographic Investigation of Liquid Fuel Sprays,” Eighteenth Symposium-
converted into local representations of the distribution and
International-on Combustion, Pittsburgh: The Combustion Institute, 1981, pp.
number density. 1501–1510.
E1620 − 97 (2012)
even spray atomizer, n—a fan spray atomizer that produces a hollow cone pattern, n—a cone pattern wherein most of the
relatively uniform band of liquid, usually by means of liquid is concentrated near the outside of the pattern.
injection, through an elliptical orifice. (This definition ap-
hydraulic atomizer, n—see pressure atomizer.
plies to devices utilized in the agricultural industry.)
impact atomizer, n—a pressure atomizer in which a spray
external mixing pneumatic atomizer, n—a pneumatic atom-
pattern is achieved by the impaction of one or more liquid
izer in which pressurized gas is directed on a liquid film or
jets against a solid surface.
jet outside the nozzle, so as to form a spray.
impingement atomizer, n—in rocketry, an impinging jet
fan pattern, n—a spray pattern in which the liquid flux is
atomizer; in industrial processing, an impact atomizer.
concentrated in a narrow oval or ellipse in a plane perpen-
DISCUSSION—Sincethistermisambiguous,itisnotrecommendedfor
dicular to the spray axis.
describing either device.
fan spray atomizer, n—apressureatomizerthatproducesaflat
impinging jet atomizer, n—a pressure atomizer in which
sheet of liquid that collapses into particles. The angle or
atomization is achieved by the external collision of two or
width of the sheet is controlled by the shape of a slot or oval
more liquid jets.
discharge orifice, by an external deflector, or by impinging
initial spray angle, n—the plane angle of the spray emerging
jets.
from the nozzle discharge orifice.
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