liquid propellant rocket chamber are presented. The use of the Phase Doppler Particle ... RL10A-1 and Space Shuttle ..... of a solid fluid structure ..... of a Booster.
NASA-CR-193339
SHEAR
COAXIAL
INJECTOR
COMBUSTING
S. Pal',
M.
AND
ATOMIZATION
PHENOMENA
NON-COMBUSTING
CONDITIONS
D. Moser t, H. M. Ryan t, M. J. Foust t and R. J. Santoro*
Propulsion
Engineering
Research
/,,u
Center
Department The
of Mechanical
Pennsylvania
University
Associate,
Graduate
Student,
Professor,
Mechanical Mechanical
Mechanical
Park,
-j
/85
and
Research
FOR
State PA
y-_,,_
B
p. .31
Engineering University 16802-2320
Engineering Engineering
Engineering
(NASA-CR-193339) SHEAR COAXIAL INJECTOR ATOMIZATION PHENOMENA COMBUSTING AND NON-COMBUSTING CONDITIONS (Pennsylvania State Univ.) 39 p
FOR
N9_-11526
Uncles
G3/34
0180877
f
6
ABSTRACT Measurements chamber
are presented.
averaged
The
probability
demonstrated. conditions cold
of LOX
are
drop size and velocity
use of the Phase
density
functions
measurements
also
The drop
presented.
flow conditions
are compared,
Doppler
of drop
Complementary
in a uni-element Particle
size
Analyzer
in a harsh
and the results
made
that there
rocket
temporally-
environment
for simulants
measurements indicate
propellant
in obtaining
rocket
of drop size/velocity
size/velocity
liquid
has
under
been
cold flow
for combusting
are significant
and
differences
in the two flowfields. INTRODUCTION
The propellant either
steady
state combustion
process
injection,
atomization,
vaporization,
injected
in gas
phase
Clearly,
the process
starts
and
mechanism
in turn
this
chamber. injectors,
The with
considerations.
fluid
swirl
injector
RL10A-1 used
of choice
has
been
Space
in the RL10A-3
has
proposed
The
shear Engine
process
oxygen
been
the
rocket
manner,
and
atomization
and combustion
dictated
for the liquid
characteristics. and
and subsequent
atomization usually
liquid
involves
type
Shuttle
Main
[1] and
is also proposed
injector
(SSME)
use
has been
propellant,
a
rocket
manifold
(GH2)
propellant recently
because
of its
Transportation
of
stability
although
coaxial
is
combustion.
in the
of
successfully
[1] and the swirl
liquid which
and combustion
injector,
for use in the Space
2
finally,
hydrogen
as an alternative/advancement coaxial
propellant
of the liquid
the
(LOX)/gaseous coaxial
includes
characteristics
by propellant
shear
engine
with its counterpart
in a similar
the flowfield
and
the type of injector
the element
atomization'
defines
Historically,
mixing
is vaporized
with the injection
injection
combination, coaxial
or
in a bi-propellant
used
the 'self-
in the J-2,
injector Main
has been Engine
q I
(STME)
[2].
For liquid/liquid
propellant
tetroxide(NTO)/monomethyl injector.
Engines
combinations
hydrazine
which
have
used
(MMH),
like RP-1/LOX
the element
impinging
injectors
or storables
of choice
include
like nitrogen
has been
the F-l,
H-l,
the impinging
Titan
and
XLR-
132 [1]. Understanding
the physics
for understanding
the subsequent
of
can
understanding
size/velocity models for
fields
based
drop
either
based
on
correlations
distribution
data
atomization
models
conditions
to predict
physical
parameter
number
for
combusting could
analytical
for combusting
conditions.
drop space
size
flow Finally,
for developing
the steady
linear
stability
conditions
is therefore
of extrapolating
drop
of pressure,
experiments a drop
correlations
is
size
significantly
that are directly
3
[3-5].
input
the
Reynolds
base
data
incorporated
in
phenomena
A data
obtained
of
base of drop both
for cold flow
to realize number
from
that
for combusting
into CFD
base
consequently,
for verifying/refuting
different
data
drop
or extrapolations
It is important
temperature,
distribution
are
level
and theoretical
and
that
size correlations
conditions.
evolving
Currently,
theory
critical
is critical This
state combustion
for cold flow conditions
for combusting
in terms
cold
for predicting
the
conditions,
is minimal
distributions
such as
both
measurements.
size
injector
and combustion.
detail
combusting
conditions
drop
size obtained
and the practice
typical
be used
treatments
of drop
the
combusting
codes
mixing that
field under
initial
(CFD)
for a particular
experiments
velocity
under
predicting
fluid dynamics
parametric size
for
by
that corroborate
fields
process
of vaporization,
obtained
on first principles
models
computational
be
dynamics
and the gas phase
size/velocity
atomization
are
only
of the atomization
codes.
that
and
the
Weber
found
for
conditions
The numberof experimentsdesignedin the pastto addressthis void in drop sizedatafor combustingconditionsis minimal becauseof the generallack of diagnostictechniquescapable of probing the harshenvironmentin a liquid propellantrocketchamber,the safetyaspectsthat haveto fluids
be strictly
and
the
experiments for drop images
size data of the
through
to form
the
drop
water
and
the need
under
formed
cloud.
George
nitrogen
as
harsh
Researchers
environments. ranging
to characterize where
the
simulants
Goix
et al.
flame
from
from
[15]
are used
a coaxial
size
field
like-on-like
to diesel
in sprays
his
to characterize interferometry
of actual used
this technique
injector.
4
doublet
through
two
drop
[10].
(for example, for measuring
a doublet
injector
drop
experiments
sets
of thus
drop
size
indicating
where
can be obtained
drop
flow
11-14). size
in
size and velocity has also been
for cold Refs.
in a
oxidizer
to a stage
This technique injectors
holographic
sprays.
position
for measuring
the need
N204
sizes,
rocket
the
injector
cold-flow
has advanced
of spatial
by rocket
propellants
actual
from
was gaseous
of the
[8-9]
as a function
applications
knowledge,
sizes
complementary
the measured
to cryogenic
to address
impinging
comparisons
between
formed
drop
N_H4 fuel injected
conducted
and
authors'
combination
have used this technique
instead
recently
Doppler
distributions
oil burner
drop
have
experiments
phase
drop
also
hypergolic
that has attempted measured
The propellant
differences
hot-fire
last decade,
[6-7]
from
To the
George
a uni-element
simulants
significant
for additional
that range
experiments.
conditions.
chamber.
temporally-averaged
in sprays
these
on the face plate and liquid
showed
In the
propellants
[6-7] is the only program
from
thrust
holes
of
combusting
side-walled
injected
nature
by George
spray
measurements
to in handling
expensive
reported
transparent
using
adhered
used
conditions, In addition,
in a methanol/air
The present effort is geared towards systematically mapping the drop size field downstreamof a shearcoaxialinjectorin a rocketchamberthatcombustsgaseoushydrogenwith liquid oxygen. Measurementsof LOX drop size under combustingconditionsmadeusing the phaseDopplerparticleinterferometrytechniquearepresentedandcomparedwith complementary drop sizemeasurements madeundercoldflow conditionswith waterandgaseousnitrogen(GNz) as simulants. EXPERIMENTAL
The experiments
were
Penn State University. propellant oxygen
sub-scale
(LOX)
Hot-Fire
in Fig. section, The
entire
rockets. 0.11
provides
The flowrate
kg/s
rocket chamber
for laser-based 1.
for gaseous
Combustion
the capability
capabilities hydrogen
Laboratory
located
for firing both gaseous
of this laboratory
are 0.45
at
and liquid
kg/s for liquid
(GH2).
sections
along
245.6
The window that provide
while
assembly
section,
also allowing
optical
includes
access
in design
two diametrically
5
a window-section,
allowing
optical is shown
an igniter
by a hydraulic
placement
provides
here,
and provides
of the chamber
are held in place
the chamber reported
to the 50.8
view
section,
This arrangement
For the experiments section
which
can be interchanged,
the chamber.
of the chamber, blank sections.
in diameter
and a nozzle
is modular
A cross-sectional
of an injector
of the chamber
or installing mm.
approaches.
consists
blank sections
at any location length
used for these experiments
diagnostic
The chamber
several
middle
section
This laboratory
at the Cryogenic
Studies
The access
and
conducted
optical
of the windowaccess
length to be varied
along
quartz
mm square cross-section
the
by removing
the length of the chamber
opposed
jack.
windows, combustion
50.8
was mm
chamber.
The other two sidesof this section provide
additional
combustion section For
gases
diameter
by a curtain
experiments, of the
diameter
the
access.
also has a modular
these
The
optical
of
the
dimensions Space
shown
igniter
1) that
in the main changed
to vary
throat
diameter
of 11.36
the rocket
over
a wide
the
mm.
range
were
accomplished
with
instrumented
thermocouples.
The
respectively,
thus
the nozzle
dimensions
mm and 4.19
chamber.
resulting
and
the
mm from
the windows.
of injector
in Fig.
recessed
outer
3.78
diameter
which the
hot
The injector
type and/or
as shown
was
x 50.8
protected
to the fuel and oxidizer
is equipped
These
upstream LOX
in an O/F
gaseous
Finally,
design
and
geometry.
2.
The
inner
mm.
The
inner
was
7.11
mm.
pre-burner
features
elements
allow
of
of the gaseous and
downstream GH2
mass
flow ratio pressure
6
were
of 5.1:1.
of 2.74
MPa
for
can be had
a
inside
conditions.
a cavitating
flowrates
nozzle
of the combustion
(GH2) and liquid
locations
the
(not
torch
of the rocket
experiment,
the study
chamber
oxygen
nozzle
and operating
orifice
an ignition
hydrogen/gaseous
For the present
and
a chamber
with
the water-cooled
geometries
of the flowrate
yielded
mm
pressure.
of injector
nominal
across
injector
the post
chamber
the aid of a critical
at both
thermally
flows
coaxial
a spark-ignited
chamber
The setting/monitoring was
was
are
6.25
(SSME).
provides
easily
3.43
of the rocket
combustion
measuring
for easy change
are comparable
Engine
section
which
was a shear
annulus
Main
in Fig.
ignition
fuel
of nitrogen
that allows
(d) was
of this injector
Shuttle
The
purge
design
post
slot windows
All of the windows
the element
LOX
feature
venturi,
with
These
that
transducers
and
kg/s flowrates,
400 psia).
propellants
respectively,
pressure
0.113
(--
(LOX)
and
0.022
kg/s
coupled
with
The duration of a test run wasfour secondsand representsa compromisebetweenthe time required to achieve steady-statechamber pressureand quartz window survivability. For these tests, it takes in excessof two secondsfor the chamber pressure to stabilize. The causeof this rough startuptransienthasyet to be identified. However, following this two secondtransientperiod, the chamberpressureremainssteadyfor the duration of the test. The LOX These
flowfield
experiments
provided
breakup
process
velocity
using
phase
an
argon-ion
beam
of
A video record The
the
this
also
helped
was
from
experiments locations
the
used
within The
Phase
to reject
measuring
theory
[8-9].
The
above
described
liquid
PDPA rocket
technique
Particle drop
instrument chamber
presence
Analyzer size
and
was under
drop
7
of a drop
based
circular
on LOX
conditions.
drop
over the last decade
images
initial
indicated
the
be attempted. instrument
Doppler
interferometric
size
velocity
The
to
windows.
These
available
phase
used
Downstream
and
should
wave
video
field. jet
and
windows.
nm was
face.
core
size
slot
The
is a commercially
used to measure combusting
the
LOX
drop
the
514.5
flame.
size measurements
velocity
of
of
LOX
the continuous
the injector
disintegrating
(PDPA)
that has been used extensively
one
luminous
the possible
LOX
one around
through the
LOX
from
technique.
of the
measuring
centered
sheet
dynamics
through
50 mm from
of the
a laser
formed
for about
picture
where
sheet
filter
from
fluid
for
introduced
flow field
light
intact
indicated
front
Doppler
of
LOX
a qualitative
the flame
capable
measurement
images
provided
the approach
was
using
on the
A laser
nm)
the
that the LOX jet seemed location,
information
in guiding
(514.5
characterized
with a 10 nm bandpass
light
falter
visually
interferometry.
laser
equipped
first
preliminary
Doppler
scattered
bandpass
indicated of
and
camera
was
and
PDPA
by several
is
in the a
point
researchers
(for example, Refs. 8-16).
The PDPA instrument extends the basic principles of the
conventionaldual beamlaserDopplervelocimeterto obtainparticle sizein additionto velocity. An argon-ion laserbeamis split into two equalintensitybeamsand focusedto an intersection to form a probe volume as shownin Fig. 3. For the presentexperiment,the receiversystem was locatedat a 30° off axis angleto bestexploit the characteristicsof the interferencepattern of the refractiveLOX drops. This wasachievedby inclining both the transmittingandreceiving optics at a 15° angle, thus resulting in a net 30° centered
around
luminous
flame.
transmitting the
The
signal, detectors
and
angle.
The
is 1.221
index
for LOX
Flow
a priori
The
similitude.
of three
of the
detectors
by drops
is then extracted
calculated
linearity
of the liquid
between drop
being
the temporal
from
the
with
the
optics,
independently
albeit
with
frequency
phase
measured
coupled
that
volume,
the detector
light
filter
to the collection
separations
the measured
bandpass
to reject system
the probe from
from
optics
In addition
at appropriate
traversing
A 10 nm
receiving
characteristics.
size is calculated
of refraction
of the collection
optics
volume
angle.
of the
shift between
separation
enters
a phase
and
burst
any
two
the phase
into this analysis,
and
[17].
Studies
a basis design
in front
collection
of the particle
A sequence form
the
generated
the particle the
placed
the probe
consists
signal
velocity
whereas
that
define
system
the burst
shift.
nm was
Note
optics
receiving
measure
Cold
514.5
off-axis
for
of cold
flow
comparison
of the In terms
cold
flow
drop with
size the
experiments
of the geometry,
measurement drop
sizes
experiments measured
for
both
geometrical
considered
the injector
8
were
used
the
for the hot-fire
also
carried
hot-fire and
out
to
experiments. flow
experiments
parameter was
also
usedfor the cold flow experiments. To
maintain
two sets of experiments,
used
to be used
at the elevated
requires
a nozzle
obvious
hazards
for the
cold
those
associated
flow
were
for LOX
and
and GH2.
The
magnitude
greater
than
two gases The emanating pressure
instrument the
experiments, direction.
accordingly
(same of 1.33
same
used
injector
Therefore, 30 ° off-axis
with water
(_.
Consequently,
more
water
water
collection,
orientation
of refraction
but
will
the
in a different
of water
[17]
was
plane
was input
the
have
to be used The
nitrogen
cold (GN2)
between
than
the
conditions. for the spray atmospheric
to develop
instrument
of
the hot-fire
chamber
made
and
in a later
but since
these
but the
an order
be revisited
velocity
with
flowrates
are
For
PDPA
However,
difference
and
experiments.
of
and
for same
than GH2,
the spray
is possible
are compared
experiments
drop size
have
to that of LOX,
the density
the
would
matching.
the two at the actual
the hot-fire
collection
dense
MPa),
for
the
hot-fire
This point
2.74
would
of the propellants
for the
GH2,
and gaseous
different.
between
pressure.
parameter
is comparable
to measure
used
flow
of water
of two when comparing was
for the index
that simulants
exact
and
This experiment
suggested
GN2 is 14 times pressure
LOX
the elevated
flow experiments.
to accommodate
downward
The value
pressure,
for an elevated
PDPA from
cold
numbers
similitude
to achieve
properties
The density
Weber
for the
is less than a factor
physical
i.e.
MPa).
pressure
are significantly
and
At atmospheric were
1.
tension
Reynolds
experiments
throat
at atmospheric
the
2.74
thus compromising
in Table
surface
(_
conducted
geometries,
section.
pressure small
flow parameter
for the hot-fire,
with this experiment
experiments,
of the simulants
viscosities
chamber
with an extremely
flow experiments as simulants
the propellants
exact
was
shown
into the PDPA
in the changed
in Fig. analysis.
3).
The drop size measurementsfor the cold flow experimentswere for three different flowrate combinationsas shownin Table2. set at 0.009 flowrate
The
is 293
(speed 0.13
kg/s.
m/s.
of sound and
0.26
the hot-fire
mean
exit velocity
Higher
in nitrogen kg/s.
gas
from
flowrates
is 353 m/s).
Note
Three
that the three
chosen
injector,
correspond
measured
presence
flowrates
AND
so as not
flowrates
envelop
to this
to choke
were
used,
the LOX
the
flow
viz. 0.026,
flowrate
used
for
DISCUSSION
centerline. At radial is confined
and
a
63.5
four
dense radial
are
Again, locations
agrees
fluid structure drop
cloud.
distances
for
mm.
four
to a narrow
Further
be interpreted
circumferential
radial
post
than R/d of 2.8,
The
no drops region.
location,
any
only
significant
of scattered as either
d,
were
measured
d,
these
about
drops
of
liquid
core
were
up
injector
indicating before,
the or an
measured in Table
3
in Table
to 9.5 mm
this corresponds
drop
showed
are tabulated coaxial
axial
ten drops
which
an intact
extending
diameter,
downstream
number
light
LOX
and shear
As mentioned
10
locations
diameter,
drop measurements
locations,
inner
inner
(Z/d=18.5),
of the rocket
spaced
of
images
downstream
post
11.1 Z/d
The lack
with the video
that could
of LOX
of LOX
At the
run.
parameters
equally
in terms greater
18.5.
from the centerline.
operating
LOX drops at two axial
In terms
second
at this location
and the corresponding results
was used to measure
to Z/d of 11.1 and
over
of a solid
impenetrable at different
instrument
38 mm
measurements
The
water
corresponding
was
Measurements
locations were
of the injector
not considered
different
the GN2 flowrate
experiments.
The PDPA of the
combinations,
the annulus
were
RESULTS Hot-Fire
For all three
to R/d
from
4. the
of 2.8.
that the drop field
the chamber
pressure
traces
indicated
are therefore pressure.
shown
Table
diameter The
a startup
Sauter
as being
asphericity,
signal
diameter
number
spherical
drops.
to noise
that the chosen
164/_m.
There
increase
limits
decreased
optical
could
D_o and with
possibly
/)32.
duration
that the values
lead to a large rocket
(Table
different jet
4) show
that the
jet and
of the LOX slightly
The The
annular
as they
are
entrained
rejects
measured
validation
during
number
LOX
and
of the LOX jet is 13.5
the mean in the
chamber
pressure range
which,
drop
velocity
indicates
higher
velocity
coaxial
second
that gas
test
Inspection
radial
locations.
are
of the
repeatable
indicates ratio
test runs.
stream.
which
conditions
the velocity
the drops
run
pressure
operating
different
would
at the centerline
5x10 s and
4-
chamber
to the other
m/s and
period.
between
of drops.
steady
densities
the
on drop
if measured,
a four
the
by
limits.
GH 2 flowrates
26 to 29 between
11
range
mean
validation.
based
of the LOX jet is about
from
percent
measurements
density
are low compared
pressure,
the arithmetic
accepted
during
in the number
chamber
was
than 164/zm,
drops
measurements
of steady
and
that
for the steady
The corresponding
number
(Uo)
of drops
to noise chamber
size
to a size measurement
greater
errors.
drop
with
and size dynamic
corresponds
percent
velocity
drop
velocity
with
instrument
a decrease
and
GH2 flow ranges
jet velocity
PDPA
of total
The
along
a result of dense
Reynolds
mean
percentage
at the centerline
of signal
is turbulent.
LOX
drops
number
test runs.
the
with radial distance
indicating
are probably
drops
drop
and both velocity
number
of measured
low values
The
test run.
run and the time duration
mean
be a few drops
The
of the number
These
(D32),
configuration
radial distance
shows
second
of measured
represents
Both D_o and D32 decrease Note
a four
the total number
mean
validation
instrument
during
for both the entire four second
3 shows
(Dlo),
percent
transient
are
for
that the between
Comparison accelerating
Finally,
the
high
operating
Reynolds
propellant
rockets.
and Weber
The probability
density
numbers
density
for
pressure
steady
chamber
The probability skewed. steady-state stems
chamber
interval
from the order of magnitude
density
function
and indicates
time
interval
for the steady-state
that the atomization
interval
is different
density
functions
(1.03
liquid
for Run 2 (Table 3) is shown
is "noisy" difference
phenomenon
from that during
compared in sample
time interval
sec.)
are
depicted
in this
figure.
peak between 20 to 30/_m, and are positively
from the figure that the probability pressure
in actual
function of drop size for both the entire four second test and
density functions are mono-modal,
It is evident
to those encountered
function of LOX drops measured
in Fig. 4. The probability the
are comparable
density
function
of drop size for the
to that for the entire size.
Furthermore,
has larger moment
during the transient
the steady state chamber
the probability
diameters
(D_o, D_2, etc.)
chamber pressure pressure
test run and
interval.
startup time Probability
for the other test runs show the same trends.
Cold Flow Measurements Drop size and velocity measurements with the PDPA instrument.
The measurements
were made at one axial location, axial location, direction. A typical
drop size/velocity
For some cases,
for all three parametric
50.8 mm (Z/d= 14.8) downstream measurements
measurements
data set for the calculation
drop size/velocity
were made in the water/GN2
coaxial injector sprays conditions
of the injector
were made at 3.18 mm intervals
at finer radial intervals
of the various mean diameters
measurements.
12
(1.59
(see Table 2) face.
At the
in the radial
mm) were also made.
included
in excess of 8000
The distance,
R/d,
exit gas 2.9,
measured
highlight
and
from 28.3
at the centerline,
PDPA
flow
decreases
measurements
their
measurements
at greater
edge
of the spray.
From
part
of
edge
spray, gas
The For
from
maximum that
the
centerline, mean
mean
gas the
velocity
drop
> 5, D_
drop
phase bigger because
size,
mean
drop the
and
velocity velocity
ratio),
then
shown D32,
drops
the larger
approaches
velocity
increases
for greater lower
than the mean
considerably
at
to the higher more
13
slowly
near
this
exit
The
to the gas flow
the
value. in Fig. with value
6.
radial of the
suggesting
location.
flowrates
(or
near
manner
gas velocity
axial
liquid
the central flowrate
the same
distances.
in
size at the
However,
to a maximum
radial
trends
However,
water
in a similar
near
[14] also reported
that
increasing
flow conditions Uo, is plotted
similar
in drop
5, it is evident with
slightly
to the injector. increase
are
therefore
increases
et al.
atomization.
decreases
respond
close
velocities
D32 is maximum
[13] observed
poorer
corresponding drops
and finally
the slight
increases
drop
decelerated
flow condition,
location
the mean
measurements
Hardalupas
in Fig.
indicating
is significantly has
sprays.
did not show
velocity,
mean
each
radial
conditions,
the liquid
these
and Chigier
at an axial
for all three
mean
combination,
the centerline
mean
to a minimum
locations
momentum
R/d
flow
distance
the measurements
complementary
a given
distance
the
axial
For
flow
whereas
between
size.
injector
nondimensionalized
For all three
on drop
trends
versus
is 293 m/s,
[12] and Eroglu
with similar
to liquid
of the spray,
flowrate
of drop size in coaxial
size
5.
Comparisons
with radial
drop
decreasing
in Fig.
of the injector
Both Zaller
measurements
(D3z) is plotted
conditions
respectively.
of liquid
of the spray.
the
diameter
the annulus
m/s,
the effects
the edge
mean
for the three
velocity
14.3
Sauter
Near have
than smaller
the
a lower drops.
As mentioned before, the PDPA instrument rejects measurementsbased on drop asphericity, signal to noise limits and both velocity and size dynamic range limits. The corresponding percent validation and samplesper second for the drop size/velocity measurements aredepictedin Figs. 7 and8. For thetwo lower liquid velocity cases,thepercent validation at all radial measurement locationsrangesbetween80 to 90%. Thesehigh validation percentagesfor PDPA measurements are characteristicof locationswithin sprayswheredrops are sphericalandthe signalto noiseratio the percent
validation
is low
completely
atomized
into
can be gained
plot,
For all three
Fig.
8.
at and near
spherical
characteristics
velocity
increases
distances.
For
significant
(>
1500/s),
whereas
validation
and
samples
per
spray For
at the axial
could
that
the
be large
spray
ligament
Hot-Fire/Cold The cold in terms
liquid
of flow
cases,
the
the
second
results
location
is not completely structures
Flow
Comparisons
flow
and hot-fire
insight
samples
measured
measured
indicate
that on
the
the
versus
per
then
decreases
samples
per
cases,
it is near
completely,
i.e.
the low number
of samples
atomized,
the liquid
not
development location
is low
at the radial
at the centerline zero.
per second
The
velocity
all the drops
could
case, has
for greater
liquid
jet
jet
radial
second
second
velocity
liquid
spray
samples
that for the lowest
i.e.
liquid
per second
and
velocity
is atomized
cases,
indicating
Additional
to a maximum
case,
for the highest
centerline,
for the two highest
velocity
parameters.
However,
the measured
distance
velocity
measurement
the two highest
suggest
with radial
the
drops.
by perusing
centerline,
the lowest
is high.
is
percent case,
the
are spherical. at the centerline
be intact
or there
present.
experiments
However,
were
in terms
14
identical
in terms
of both liquid
of geometry
and gas
flowrates,
but differed the hot-fire
experimentwas comparableto the secondcold flow experiment(Table2, case2). Therefore, a comparisonof the drop size/velocitymeasurements for thesetwo casesprovidessomeinsight on the generaldifferencesbetweenhot-fire andcold flow experiments. A comparisonof theflow parametersfor boththehot-fire andcold flow (Table 2, case2) experimentsis presentedin Table5. The flow parameterslistedarethe chamberpressure,mass flowrates and velocities for both the liquid and the gas, the mass flowrate, velocity and momentumratios betweenthegasandthe liquid, the Reynoldsnumberof the liquidjet, andthe Weber number. The hot-fire to cold flow parametricratios are also presentedin the table. For example,the ambientpressure,Pc, for the cold
flow experiment,
experiments, number The
it is readily
and
Weber
chamber
atomization
Reynolds different
the and
dynamic
the drop makes
in Figs. cloud intuitive
and
and 9 and
extends sense
mean
the
gas
that
differ
These
two
surface
drop
because
drops
parameters
only
Therefore,
in
differ
because
the radial
15
for the cold and
Reynolds
of magnitude.
contribution comparing
to the
of magnitude LOX
and
the two
are
water
the have
1).
The D32 measurements
vaporize
order
its
an order
for the two
pressure,
the same
variations
Uo, for both the hot-fire
direction
and 0.1 MPa
the parameters
than
(see Table
differences,
velocity,
within because
by greater
experiment
of the chamber
density.
tensions
in the radial LOX
are
importance
10, respectively. further
In comparing
parameters
in mind the aforementioned
diameter,/932,
compared
parameters
viscosities
of 26.3.
of primary
numbers.
MPa for the hot-fire
that with the exception
is to affect
only
Weber
a ratio
all the other
is not
phenomenon
Keeping mean
discerned
number,
pressure
experiments,
yielding
was 2.67
combust
and cold
compared flow
of measured
case.
whereas
flow cases
in Fig. This water
Sauter
9 show
are that
observation drops
do not
evaporate. The measureddrop size for the hot-fire caseis also larger than for the cold flow case. At first glance,the differencesin flow conditionsbetweenthe two experiments(Table5) makesany comparisonbetweenthe two spraysseemfutile. However, a thoughtexperimentis helpful here. If oneenvisionsa cold flow experimentwith the samewater and GN2velocities, but at an elevatedchamberpressureof 0.23 MPa, then exceptfor the Reynoldsand Weber numbers,all the flow parameterratioslistedin Table5 would be very closeto one. The mean drop size for suchan experimentwouldbe smallerthanthemeasureddrop sizefor the cold flow experiment shown in Fig. 9, becausethe higher gas mass flowrate and momentumwould atomizethe liquidjet moreeffectively. The measurements thereforeindicatethatthe meandrop sizefor a hot-fire experimentis largerthanfor a coldflow experiment,with all flow parameters being equalexceptfor the ReynoldsandWebernumberswhich arehigher for the hot-fire case. This observationis counterintuitive and suggeststhat there are significant differencesin the atomizationprocessbetweencold flow andhot-fire conditions. The gasphasevelocity field in a combustingflow is probablyradicallydifferentfrom the cold flow casethusaltering the shear mechanismthat is responsiblefor atomization. The radial variationof meandrop velocityfor thehot-fire experimentis comparedto that for the cold flow casein Fig. 10. Here, the meandropvelocity for the cold flow caseis greater than that for the hot-fire case. The larger dropspresentin the hot-fire casewould be expected to accelerateslower thanthe smallerdropspresentin the cold flow case. Additionally, a slower gas phasevelocity field for the hot-fire casewould producelarger drops and also retard the accelerationof the drops.
16
SUlVllVlARY Drop size andvelocity were measuredwith a PhaseDopplerParticle Analyzer (PDPA) instrumentin a uni-element(shearcoaxialinjector) rocketchamberundercombustingconditions for the liquid oxygen(LOX)/gaseoushydrogen(GH2)propellantcombination. Complementary PDPA drop size/velocitymeasurements werealsomadein thesprayfrom the sameinjector with water and gaseousnitrogen(GN2)simulatingLOX/GH2. The flow conditionsof the cold flow experimentswere similar to the hot-fire experimentsin termsof both flowratesand velocities for both the liquid andthe gas,but differedby an orderof magnitudein termsof Reynoldsand Weber numbers as depictedin Fig. 11. The hot-fire experimentis similar to actual rocket conditionsin termsof theseparametersas seenin Fig. 11. The ReynoldsandWeber number rangesfor other cold flow experiments(Refs. 12-14)are alsoat least an order of magnitude lower than actualrocketconditions. The drop sizecomparisonsbetweenthe cold flow andhotfire conditionsshowedthat the dropswerelarger for combustingconditions,suggestingthatthe gasphasevelocity field betweenthe two flowfields is significantlydifferent. ACKNOWLEDGEMENT Funding State NASA
by NASA
Propulsion
acknowledged. experiments, the uni-element
Marshall
Engineering
The authors Mr.
W.
rocket
Space
chamber,
Research
thank
E. Anderson
Flight
Mr.
and Mr.
Center,
Center,
L.
Contract
Schaaf
D. Harrje
and Mr. S. A. Rahman
17
Contract
for
his
NAS
NAGW
8-38862 1356
assistance
for their contributions for his comments.
in
and the Penn
Supplement
5, is
conducting to the design
the of
NOMENCLATURE English
Symbols
d
inner
D
drop
F
fuel
diameter
of LOX
post
diameter (gaseous
mass
hydrogen)
flowrate
0
oxidizer
R
radial
Re
Reynolds
(liquid
oxygen)
distance
number
(=ptUfl/tzt)
based
on liquid
properties,
liquid
jet
velocity
and
post
velocity
and
post
diameter U
velocity
We
Weber
number
(=pt(UfU_)2d/tr)
based
on
diameter Z
axial
distance
Greek
Symbols dynamic
p
density
tr
surface
viscosity
tension
Subscripts D
drop
g
gas
l
liquid
18
liquid
properties,
relative
10
arithmetic
32
Sauter
mean
mean REFERENCES
.
2.
o
Liquid
Rocket
Hulka,
J.,
LOX/H2
Joint
Propulsion
°
°
Conference, Schuman,
George,
George,
Interactive
Manual, D. J.,
W.
Measurements pp.
T. Design
V.,
"Rocket
Injector
June
Hot
Las Vegas,
Meeting, M. J.,
C.
1087109,
CA.,
Distribution,"
19
for Coaxial
Release
(SDER)
Manual
for
Program,"
Rocket
Volume
1-
1991.
Flow
Spray
5-7,
Combustor
September Spray
Fields,"
AIAA/SAE
1973.
for Rocket
"Phase/Doppler
583-590.
Energy
"User's
May,
November
Functions
Size and Velocity
Manual
Computer
and Cold
Pasadena,
1991.
"Operating
W.,
and Analysis
NV.,
27th
1978.
Johnson,
Firing
AIAA/SAE/ASME
Distributed
AFRPL-TR-78-7,
Report
of a Booster
1974.
"Standardized
and
and Stability
24-26,
W. D.,
CR- 129031,
Size Distribution
and Houser,
of Drop
"Performance AIAA-91-1877,
CA,
(ROCCID)
Contractor
Combustion D.
D.G.,
NASA
D. J., "Droplet
Injector,"
NASA
Report,"
Conference,
11 th JANNAF Bachalo,
Final
Nguyen,
9th Propulsion
.
Model,"
Program A.,
Element
C. E.,
1976.
M. D. and Chadwick,
Computer J.
SP-8089,
Sacramento,
M. D. and Beshore,
User's
.
Coaxial
Schuman,
Muss,
NASA
J. A. and Dexter,
Combustion
Combustor
.
Swirl
R. D.,
Injection
Injectors,
Schneider,
Class
Sutton,
Engine
9-13,
Analyzer
Optical
Spray
Field,"
1974. for Simultaneous
Engineering,
23,
1984,
,
Ibrahim,
K.
M.,
Considerations
for
International Lisbon, 10.
Liquid W.
11.
Portugal, Panicle
D.,
Vassallo,
P.,
P. G. (eds.),
Water/Air 13.
14.
N.,
M.
and
H. and Chigier,
Coaxial
Atomisers,"
Earth-to-Orbit
ASTM,
D.,
Doppler
of Laser
"Signal
Processing
Applications,"
Techniques
2nd volume,
Philadelphia,
Boorady,
Water
Klein,
Eroglu,
Y.,
Phase
W.
The
of Fluid
Fifth
Mechanics,
F.
Jets,"
Hirleman,
E. D.,
Bachalo,
1990.
A.,
Journal
"Effect
of Flow
of Propulsion
Rate
on
and Power,
the Vol.
Spray 8, No.
pp. 980-986.
as Simulants,"
Hardalupas,
and
Bachalo,
Techniques,
and
of Impinging
M.
and
1990.
Measurement
1992,
D.
Doppler
9-12,
Ashgriz,
5, Sept-Oct.
G.
on the Application
July, Size
Felton,
Zaller,
Laser
Symposium
Characteristics
12.
Werthimer,
M.
D.,
"Coaxial
Injector
NASA-TM-105322, N. A.,
Journal
of Fluids
McDonald, Propulsion
"Initial
November,
Drop
Characterization
Engineering,
113,
J. H.,
NASA
Using
1991.
Size and Velocity
H. and Whitelaw, Technology,
Spray
Distributions
1991,
"Two
pp. 453-459.
Fluid
Conference
for Airblast
Mixing,"
Publication
Advanced
3174,
Vol.
II,
1992. 15.
Goix,
P.
J.,
Methanol/Air Imaging
and
the Western
Cessou, Coaxial
A.,
Stepwoski,
Reacting
Spray
Two-Component States
Section,
D.
and
Edwards,
near the Stabilization
Phase-Doppler The Combustion
1992.
20
C. Region
Interferometry," Institute,
F.,
Oregon
of
a
by OH Fluorescence
1992 State
"Structure
Spring University,
Meeting March,
of
16.
Ryan, H. M., Pal, S., Lee,W., andSantoro,R. J., "Drop Distribution Effectson Planer Laser Imaging of Sprays,"Atomization
17.
Weast,
R. C. (ed.),
Handbook
and Sprays,
of Chemistry
21
Vol.
and Physics,
2, No. 2, 67th
1992,
edition,
pp.
155-177.
p. E368,
1986.
Table 1: LOX
Property
Comparisons
WATER
GH2 (@STP)
p (kg/m 3)
# (xl0 5 kg/m
s)
a (xl0 "3 kg/s 2)
GN2 (@STP)
899
998
0.085
1.25
8.25
98.8
0.872
1.73
4.8
73
-
-
Table 2:
Flowrate
Comparisons
HOT - FIRE
COLD
FLOW
2
m_(kg/s)
0.112
0.026
0.13
0.26
Ut (m/s)
13.5
2.9
14.3
28.0
rh, (kg/s)
0.021
0.009
0.009
0.009
Ux (m/s)
381
293
293
293
Table
Run
3:
PDPA
Results
R
Dzo
D_2
Uo
(mm)
(#m)
(_m)
(m/s)
No.
of
% Val.
Ran
Time
Drops
(sec.) 0.00
2
3.18
6.35
4
9.53
33.0
84.2
17.2
3756
42 %
4.00
53.2
114.9
17.6
149
16%
1.41
33.6
86.3
17.0
3791
39%
4.00
45.1
109.7
17.9
484
21%
1.03
29.8
68.1
15.5
1136
56%
4.00
28.2
71.0
17.2
448
46%
1.52
27.7
97.8
16.7
115
53%
4.00
26.8
57.5
12.9
45
62%
0.82
Table 4:
Run
Rocket Chamber
Conditions
and Flowrates
Chamber
LOX
GH:
Mixture
Momentum
Velocity
Re
We
Pressure
Flowrate
Flowrate
Ratio
Ratio
Ratio
(xlO 5)
(xlO')
ras
rn_lths
ras/rat
ff:lO)
(MPa)/
rh_
(psia)
(kg/s)
(kg/s)
(O/F)
(F/O)
1
2.79/404
0.120
0.021
5.6
4.70
26.8
4.97
1.61
2
2.72/395
0. 110
0.021
5.2
5.58
29.2
5.11
1.95
3
2.73/396
0.113
0.021
5.3
. 5.19
27.9
5.25
2.07
4
2.43/352
0.103
0.019
5.5
5.41
29.3
4.80
2.59
Table
5:
Hot-Fire/Cold
HOT
- FIRE
Flow
COLD
Comparisons
FLOW
(CASE
2)
RATIO (H.F./C.F.)
Pc (MPa)/
2.67
0.1
(psi)
387
14.7
Pt (kg/ma)
899
998
0.90
ps (kg/m 3)
2.24
1.25
1.79
rnt(kg/s)
0.112
0.13
0.85
m s (kg/s)
0.021
0.009
2.3
ras/mt
5_4
14.5
2.7
Ut (m/s)
13.5
14.3
0.94
U s (m/s)
381
290
1.3
w,/u,
28.3
20.3
1.4
mgu,/m_ut
5.3
1.4
3.8
Re
5.03
x 105
We
2.06
x 105
4.86
x 104
4.3 x 103
26.3
10.3
48
FIGURE CAPTIONS Fig. 1. Cross-sectionalview of the optically accessiblerocket chamber. The chamber is modular in designand allows for changeof the chamberlength, injector assembly,windowsectionlocation and nozzle. The interior of the chamberis 50.8 x 50.8 mm. For the results presentedhere, the length of the chamberand nozzle throat diameter are 245.6 mm and 11.36mm, respectively. Fig. 2. Schematicof the shearcoaxialinjector. Fig. 3.
Phase Doppler Particle Analyzer (PDPA) setup for making drop size/velocity
measurements in the uni-elementrocketchamber.Both thetransmittingandreceivingoptics are positioned15°
from
measurements.
The
be traversed 25.4
through
mm thick,
50.8
the horizontal optics
plane
are mounted
the spray.
Optical
mm diameter
to yield a net 30 ° off-axis on translation access
quartz
stages
through
windows.
angle
that is required
thus allowing
two sides
the probe
of the rocket
In the rocket,
was
for the
volume
to
afforded
the GH2 and LOX
by
flow
into
2 (Table
3).
the page. Fig.
4.
The
The
measured
1.03
second
Fig.
5.
Fig. shear
size
drop
size number
steady Sauter
water/GN2 Table
drop
shear
number
pressure mean
distribution
portion
diameter
coaxial
distributions
injector
measured
by
for both the entire
of the same
firing
PDPA
for
four second
Run
rocket
firing
and the
are shown.
(D3z) versus
nondimensional
sprays.
flowrate
The
the
radial
distance
(R/d)
for
are
listed
and
velocity
conditions
radial
distance
(R/d)
the
2.
6.
Mean
coaxial
drop injector
velocity sprays.
(Uo) versus
nondimensional
The flowrate
and velocity
conditions
are
listed
for the water/GN2 in Table
2.
in
Fig. 7.
Percent
distance
(R/d)
conditions Fig.
validation in the
are listed
8.
The
flowrate
Fig.
9.
of
radial
and
velocity
Comparison
between
hot-fire
in Table
Fig.
Comparison
between compared Fig.
11.
experiments
hot-fire
size
coaxial
measurements injector
versus
sprays.
The
nondimensional flowrate
radial
and
velocity
samples
per
distance
(R/d)
mean
second in
for the
are listed diameter
flow conditions.
PDPA
water/GN2 in Table
(D3z) versus The
drop
size
shear
measurements
coaxial
versus
injector
sprays.
2. nondimensional
flow parameters
radial
distance
(R/d)
for the two measurements
are
5. of mean
and cold
in Table
drop
velocity
flow conditions.
(Uz_) versus The
nondimensional
flow parameters
radial
distance
(R/d)
for the two measurements
are
5.
Comparison with
shear
conditions
and cold
drop
2.
of Sauter
compared 10.
water/GN_ in Table
Number
nondimensional
for PDPA
other
of Reynolds cold
versus
Weber
flow experiments
number
(Refs.
ranges
12-14)
for the cold
and examples
flow
of actual
and
hot-fire
rockets.
/Nitrogen
Gaseous
Hydrogen
Purge
-_
_
f 1
Slot r-1
Window/ r_
Igniter Cooling Water
InX
t oLiq_dn _
iTM
_
Viewing
Window Water Out Cooling 245.6 mm
LOX
_,'2
2_
TRANSMITTING
DPTICS LASER
THREE
BEAM
DETECTORS RECEIVING
OPTICS
RACKET
15 °
i5 °
WINDDWS
TRANSLATIDN STAGE
0.040
Z--63.5 R=3.18
mm mm
4.00 sec. Run Time 1.03 sec. Run Time
0.050
0.020
0.010
0.000 0
50
100
150
200
D (,u,m)
1_
' "*
L/
160
d = 3.4,3
Ug = 293 m/s
120 E :::L
mm
U j = 2.90
m/s
0 ..... 0
UI =
m/s
0 .....
U I = 28.0
a
80 "°
ro
0
14..3
m/s
",
a A
• .:"o ........ o.... ..::_;;;;;,,_' ,:_ :::::_::::....
40
0
0
I
t
I
t
2
4
6
8
R/d
10
100 d = 3.43
8O
Ug = 293 m/s A
C/1
60 ...._.-:-"
E .'"
tm
40
mm
• -0
'_,
18-.-
A
U I = 2.90
m/s
0
.....
0
UI =
14.3
m/s
0
.....
0
U I = 28.0
m/s
! ql!l
.....
"
°
..5
2O
0
½
I
I
4
6 R/d
;_
10
100
d = 3.43
mm
Ug = 293 m/s U i= 2.90 m/s 0 ......
0
U I = 14.3 m/s
0 ......
¢
U i=
_J
0
0
28.0
I
I
I
I
2
4
6
8
m/s
0
R/d
_,q
"_
15 d = 3.43 0 0 0
12
•
i
U 9 = 293 .O-
U i=
•
I,I J
0
9
c
m/s
0 .....0
U I =
i4..3
m/s
U i=
28.0
m/s
.•
•.
;----.
6
n < (/3
, •
°. ,
°.
.....0
0:: °
•
2.90
°
X
O3
m/s
,°
•
(.3 i,i (/3
mm
°
• • o • w
3 •
°
• •°
70. °
0
0
!
I
I
6 Rid
10
160 d = 3.43 mm
120
D k...
•"
E :::L
HOT
RRE
(Z/d=18.5)
80
¢'4
iE3 z_ "13
40
. .13 ,,•
.°°..rl* ,13.-" • ,
,°
13.......
COLD
FLOW
"13""
(Z/d=
14.8)
0
10 R/d
I00 d = 3.43
mm
8O °°,'_ 0
(/1
6O
o o
E r_
.°
0
COLD FLOW (Z/d=
14.8)
"0.
4O
"°°0
°'"..0...
2O
HOT FIRE (Z/d= ,o,,...°_..,.
....
0
18.5)
J_.,., ".,.°
0
0
I
2
I
I
4
6
1
8
10
Rid
:F,%
PO
10 6 J-2
v
HOT-FIRE
(LOX/GH2)
•
COLD FLOW (WATER/GN 2 )
v
• --
•
SSMEFPB RL IOA
[] SSME-OPB
10 5 q) CE
HARDALUPUS et ol. [14] 10 4 ZALLER AND KLEM [12]
I0
3 I
10 _
10 2
I
10 3
I
I
10 4
10 5
10 6
We
Fi ,
II
