ASTM E1620-97(2004)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1620–97 (Reapproved 2004)
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.
1.2 All terms, followed by their definitions, are arranged
2. Referenced Documents
alphabetically. In addition, the terminology contains several
2.1 ASTM Standards:
tables wherein terms related to specific subjects are segregated
D1356 Terminology Relating to Sampling and Analysis of
and identified.
Atmospheres
1.3 Within the broad scope, the following specific catego-
E799 PracticeforDeterminingDataCriteriaandProcessing
ries are included:
for Liquid Drop Size Analysis
1.3.1 Terms pertaining to the structure and condition of
individualparticlesorgroupsofparticlesasobservedinnature.
3. Terminology
1.3.2 Terms pertaining to the structure and condition of
aerating nozzle—a device to atomize liquid for the purpose of
individual particles or groups of particles produced by an
aeration.
atomizing device.
1.3.3 Terms pertaining to atomizing devices according to
NOTE 1—Although this term is occasionally used to designate certain
the primary energy source responsible for spray development.
types of airblast or internal mixing pneumatic atomizers, it is ambiguous
(When more than one term is used for the same device or class
and is not recommended for describing the latter devices.
of devices, the alternative term is followed by the preferred
aerodynamic diameter—the diameter of a hypothetical
term.) Definitions of the devices may refer to their construc-
sphere having a specific gravity of unity and the same
tion, operating principle, or distinctive spray characteristics.
settling velocity as the actual particle.
The atomizers, however, are not classified by their respective
aerosol, n—adispersionofsolidparticlesorliquidparticles,or
areas of application or end use. Moreover, the listed terms are
both, in gaseous media. (D1356)
generic and do not include brand names, trademarks, or
air assist nozzle—a pneumatic atomizer in which pressurized
proprietary designations.
air is utilized to enhance the atomization produced by
pressurized liquid. The air may be required only for part of
the operating range (for example, low liquid flow rates).
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 May 1, 2004. Published May 2004. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1994. Last previous edition approved in 1997 as E1620 – 97. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E1620-97R04. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1620–97 (2004)
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
large volume of low-pressure air.
Functions
NOTE 2—The term is occasionally used to designate the entire class of
Aerodynamic Diameter
pneumatic atomizers.
Area (surface) Mean Diameter
D D D D
Nf, Lf, Af, Vf
aspirating nozzle—see siphon nozzle.
De Brouckere Diameter
Equivalent Volume Sphere
atomization, n—the process of atomizing.
Diameter
atomize, v—to transform bulk liquid or slurry into particles.
Evaporative Diameter
Herdan Diameter
atomizer, n—a device for atomizing.
Linear (arithmetic) Mean Diameter
Berglund-Liu atomizer—a vibratory atomizer in which a
Log Normal Distribution
piezoelectric transducer transmits high-frequency oscilla-
Mean Diameters
Normal Distribution
tions to a liquid stream discharged through an orifice,
Nukiyama-Tanasawa Distribution
creating relatively uniform drops whose size is a function of
Relative Span
the frequency of oscillation and the flow rate of the liquid
Rosin-Rammler Distribution
Sauter Mean Diameter
through the orifice.
Square Root Normal Distribution
blast nozzle—see pneumatic atomizer.
Stokes’ Diameter
Upper Limit Log Normal breakup, n—liquid disintegration that occurs during atomiza-
Distribution
tion.
Volume Mean Diameter
breakup length, n—the distance between the liquid discharge
point of an atomizing device and the point where liquid
breakup commences.
bypass nozzle—see by-pass nozzle.
air atomizing nozzle—see pneumatic atomizer. by-pass nozzle—a swirl chamber atomizer containing by-pass
air blast nozzle—see airblast nozzle. orifice(s) or port(s) through which part of the inlet liquid
airblast nozzle—apneumaticatomizerthatutilizesarelatively may be withdrawn from the swirl chamber and returned to
E1620–97 (2004)
the supply tank or pressure pump suction. The discharge dispersion, n—the spread of values of a frequency distribution
flow is modulated by controlling the pressure in the bypass about an average (in statistics). (Quantitative measures of
line, using a valve in the line. dispersion include range, variance, standard deviation, mean
cavitation, n—the formation of vapor-filled cavities in the deviation, and relative span.)
interiororonthesolidboundariesofliquidsinmotionwhere
doublet injector—an impinging jet atomizer in which there
thepressureisreducedtoacriticalvaluewithoutachangein are two colliding liquid jets.
ambient temperature.
drop, n—a single liquid particle having a generally spheroidal
centrifugal atomizer—a device wherein a rotating solid shape.
surface is the primary source of energy utilized to produce a
droplet, n—see drop; also a small drop.
spray.
dual orifice nozzle—a swirl chamber atomizer containing a
primaryinjectorandaconcentricannularsecondaryinjector,
NOTE 3—Alternatively, an atomizer that rotates to distribute the liquid.
each injector comprising a separate orifice and set of
centrifugal pressure nozzle—see swirl chamber atomizer.
tangential slots. The nozzle is normally operated only with
circumferential patternation, n—measurements taken in a
the primary injector at low flow rates, with secondary liquid
circumferential direction, showing the variation in liquid
introduced at a specified pressure. (This definition applies to
flux about the nozzle axis.
devices used in the gas turbine industry.)
cloud, n—any collection of particulate matter in the atmo-
duple nozzle—see dual orifice nozzle.
sphere dense enough to be perceptible to the eye, especially
duplex nozzle—a swirl chamber atomizer comprising a single
a collection of water drops. (D1356)
discharge orifice and two sets of tangential slots, each with
coalescence, n—the merging of two or more liquid particles to
a separately controlled liquid supply. The smaller (primary)
form a single liquid particle.
slots supply liquid at low flow rates, and both sets (primary
concentration—see number density.
and secondary) are utilized as flow increases.
cone atomizer—an atomizer that produces a conical spray
effervescent atomizer—an internal mixing pneumatic atom-
pattern.
izer in which gas bubbles are dispersed in the liquid stream.
cone pattern, n—a diverging spray pattern that is nominally
electromagnetic vibratory atomizer—a vibratory atomizer in
symmetric about the nozzle axis and whose apex is located
which an electromagnetic transducer transmits high-
at or near the nozzle discharge orifice.
frequency oscillations to the liquid.
cone spray nozzle—see cone atomizer.
electrostatic atomizer—a device wherein an electric charge is
convolution—the combination of local measurements of drop
the primary source of energy utilized to produce a spray.
size distribution and number density into equivalent line-of-
emitting spray angle, n—see initial spray angle.
sight values of drop size distribution and optical extinction.
equivalent volume sphere diameter—the diameter of a hy-
D ,D ,D ,D —diameters such that the cumulative num-
Nf Lf Af Vf
pothetical sphere having the same volume as the actual
ber of particles, (N), length of diameter, (L), surface area,
particle.
(A), or volume, (V), from zero diameter to these respective
even flow atomizer—see even spray atomizer.
diameters is the fraction, (f), of the corresponding sum for
even spray atomizer—a fan spray atomizer that produces a
the total distribution.
relatively uniform band of liquid, usually by means of
Example:
injection, through an elliptical orifice. (This definition ap-
D is the volume median diameter; that is, 50 % of the
V0.5
plies to devices utilized in the agricultural industry.)
total volume of liquid is in drops of smaller diameter and 50 %
external mixing pneumatic atomizer—a pneumatic atomizer
is in drops of larger diameter.
in which pressurized gas is directed on a liquid film or jet
deconvolution—a procedure by which line-of-sight measure-
outside the nozzle, so as to form a spray.
ments of drop size distribution and optical extinction are
fan pattern, n—a spray pattern in which the liquid flux is
converted into local representations of the distribution and
concentrated in a narrow oval or ellipse in a plane perpen-
number density.
dicular to the spray axis.
DISCUSSION—For sprays whose drop size distributions are axisym-
fan spray atomizer—a pressure atomizer that produces a flat
metric in space, anAbel inversion procedure has been used to perform
sheet of liquid that collapses into particles. The angle or
the deconvolution.
width of the sheet is controlled by the shape of a slot or oval
discharge orifice, by an external deflector, or by impinging
deflector atomizer—an atomizer in which a liquid jet spreads
jets.
out over a solid surface, forming a spray whose shape
depends upon the solid surface. flat jet atomizer—see flat spray atomizer.
dispersion, n—a system of particles distributed in a solid, flat spray atomizer—a fan spray atomizer that produces a
liquid, or gas. planar spray pattern.
NOTE 4—In agricultural applications, the spray patterns have tapered
Hammond, D. C., “A Deconvolution Technique for Line-Of-Sight Optical
edges.
ScatteringMeasurementsinAxisymmetricSprays,” Applied Optics,Vol20,Number
3,February1981,pp493–499;Yule,A.J.,AhSeng,C.,Felton,P.G.,Ungut,A.,and
flood nozzle—see deflector atomizer.
Chigier, N. A., “A Laser Tomographic Investigation of Liquid Fuel Sprays,”
flooding nozzle—see deflector atomizer.
Eighteenth Symposium-International-on Combustion, Pittsburgh: The Combustion
Institute, 1981, pp 1501–1510. flowback nozzle—see by-pass nozzle.
E1620–97 (2004)
K 3 Ln ~D/D !
gm
flux—the number of particles flowing through a given area per
f ~D! 5 ~1/ p! exp~2z !dz (1)
=
n *
2`
unit time.
flux-sensitive—a sampling process where the magnitude mea-
where:
sured responds to the flux of particles through the sampling
f (D) = the number fraction of drops of diameter less than
n
region.
D,
flux size distribution—the size distribution of particles pass-
D = the geometric mean diameter,
gm
ing through a sampling zone during a given interval of time,
K = 1/[~ 2!s ], and
=
gm
wherein individual particles are counted and sized. s = the standard deviation of the geometric mean
gm
diameter.
DISCUSSION—Flux size distributions are typically obtained by collec-
tion techniqu
...