Study of Pinch-Off and Reconnection of LiquidLiquid Flows in Micro- and Macro-Gravity
Conditions
Topic Area: Fluid Dynamics
University of Minnesota – Twin Cities
Department of Aerospace Engineering and Mechanics
107 Akerman Hall
110 Union Street SE
Minneapolis, MN 55455
Team Contact:
Eric Euteneuer
eute0002@umn.edu / (612) 378-5205
Supervisor:
Dr. Ellen Longmire
ellen@aem.umn.edu / (612) 626-7853
Team Members:
Eric Euteneuer, flight crew
Senior, Aerospace Engineering
eute0002@umn.edu / (612) 378-5205
Cecilia Ortiz, flight crew
Senior, Aerospace Engineering
orti0022@umn.edu / (612) 378-2466
Travis Schauer, flight crew
Senior, Aerospace Engineering
scha0459@umn.edu / (612) 378-9740
Christopher Teeuwen, flight crew
Senior, Aerospace Engineering
teeu0001@umn.edu / (281) 244-9871
Submitted on:
December 15, 2000
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Quick Reference Sheet
Principal Investigator: Ellen Longmire, Ph.D.
Contact Information: ellen@aem.umn.edu; (612) 626-7853; (612) 626-1558 (fax)
Experiment Title: Study of Pinch-Off and Reconnection of Liquid-Liquid Flows in
Micro- and Macro-Gravity Conditions
Flight Date(s): February 8th – 17th
Overall Assembly Weight (lbf): 370 lbf
Assembly Dimensions (L x W x H): 61 5 8  21 1 2  41 5 8
Equipment Orientation Requests:
Proposed Floor Mounting Strategy (Bolts/Studs or Straps): Bolts
Gas Cylinder Requests (Type and Quantity):
 Breathing air K-bottle (volume 233 ft3 at 2200 psig); two bottles (x2)
 K-bottle ground handling carts
 In-Flight, 9g rates, K-bottle mounting rack
Overboard Vent Requests (Yes or No): NO
Power Requirement (Type and Amps Required): 115 VAC, 60 Hz; 4.33 Amps
Flyer Names for Each Proposal Flight Days:
 Day 1
o Chris Teeuwen
o Eric Euteneuer
o Jill Burcum – Journalist
 Day 2
o Travis Schauer
o Cecilia Ortiz Duenas
1
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Table of Contents
1. FLIGHT MANIFEST............................................................................................................................... 3
2. EXPERIMENT BACKGROUND ........................................................................................................... 3
3. EXPERIMENT DESCRIPTION............................................................................................................. 4
PINCH-OFF EXPERIMENT .............................................................................................................................. 4
RECONNECTION EXPERIMENT ..................................................................................................................... 5
4. EQUIPMENT DESCRIPTION ............................................................................................................... 6
5. STRUCTURAL LOAD ANALYSIS ..................................................................................................... 11
6. ELECTRICAL LOAD ANALYSIS ...................................................................................................... 17
7. PRESSURE VESSEL CERTIFICATION ............................................................................................ 18
8. LASER CERTIFICATION ................................................................................................................... 21
9. PARABOLA DETAILS AND CREW ASSISTANCE ......................................................................... 21
10. FREE FLOAT REQUIREMENTS ..................................................................................................... 21
11. INSTITUTIONAL REVIEW BOARD ............................................................................................... 22
12. HAZARD ANALYSIS .......................................................................................................................... 22
A. HAZARD SOURCE CHECKLIST ............................................................................................................... 22
B. DETAILED HAZARD DESCRIPTIONS ....................................................................................................... 23
13. TOOL REQUIREMENTS ................................................................................................................... 24
14. PHOTO REQUIREMENTS ................................................................................................................ 24
15. AIRCRAFT LOADING ....................................................................................................................... 25
16. GROUND SUPPORT REQUIREMENTS ......................................................................................... 25
17. HAZARDOUS MATERIALS .............................................................................................................. 25
18. MATERIAL SAFETY DATA SHEETS (MSDS) .............................................................................. 26
19. EXPERIMENT PROCEDURES DOCUMENTATION ................................................................... 27
20. BIBLIOGRAPHY................................................................................................................................. 29
2
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
1. Flight Manifest
The people flying aboard the KC-135 are:
1. Eric Euteneuer
2. Cecilia Ortiz Duenas
3. Travis Schauer
4. Christopher Teeuwen
5. Jill Burcum – Journalist
Flyer Names for Each Proposal Flight Days:
 Day 1
1. Chris Teeuwen
2. Eric Euteneuer
3. Jill Burcum – Journalist
 Day 2
1. Travis Schauer
2. Cecilia Ortiz Duenas
None of our team members has been on the KC-135 before.
2. Experiment Background
There are many industrial applications today related to energy production, conversion,
and use where topological changes such as pinch-off and reconnection of immiscible
fluids are an important factor in efficiency and performance. The goals for these
applications vary from efficiently separating emulsions consisting of fine scale droplets to
maximizing mass transfer rates (such as in waste processing systems). Since these
processes are too complex to be computed based on first principles, models must be
developed. Before a model is developed, however, we must have a firm understanding of
the dynamics of these systems.
These systems are difficult to characterize experimentally and model theoretically and
numerically for several reasons: (1) the number of independent parameters affecting the
flow behavior can be large, (2) the transitions usually occur over very short time and
space scales relative to those of the local flow, and (3) the classical mathematical
description of fluid motion becomes much less reliable at transitions. It is for these
reasons that we intend to perform the proposed experiment. Specifically, we will be
examining flow structure and topology of immiscible liquid-liquid flows for a jet and a
heterogeneous mixture. The proposed experiments will allow us to vary gravity to either
increase or decrease the importance of buoyancy forces. The results of these experiments
will then be used to test the numerical models for these transitions. Once the models are
perfected, designers in various areas such as energy production and conversion, internal
combustion engines, and nozzle-spraying technologies can come up with more efficient
separation and mass transfer methods.
3
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
3. Experiment Description
The overall objectives for our experiments are to obtain qualitative and quantitative
experimental data documenting the dynamics of real transitions that can serve as a
benchmark for the computational study. Specifically:
 Experimentally characterize the dynamics of the pinch-off transitions of a fluid jet
into a bath of another immiscible fluid.
 Examine the interactions of two immiscible fluids with significant surface tension. i.e.
quantify the time it takes for two liquids, a heterogeneous mixture of the two fluids, to
separate/coalesce into two distinct fluids.
 Compare experimental results to numerical models for these systems.
Pinch-off experiment
Since the objective of this experiment is to compare micro- and macro- gravity results of
this experiment to those of the results obtained by Dr. Longmire at the University of
Minnesota under normal 1g conditions, we plan to use a similar procedure and apparatus.
We plan to use a closed-loop facility with the flow driven by a magnetic-drive pump
where the mean velocity will be controlled by a needle valve. Upstream of the test
section, the flow will pass through a honeycomb straightener before it is accelerated
through a round nozzle with a 1-cm exit diameter. The apparatus will contain a pistondriven forcer that can be used to impose a regular sinusoidal perturbation on the nozzle
exit velocity where the purpose is to create repeatable pinch-off conditions.
For this experiment, we plan to use a test section filled approximately ¾ full with a
solution of glycerin in water marked with dye. The remainder of the tank will be filled
with mineral oil. These fluids were chosen because the clear mineral oil will allow
optimal visualization of the dyed solution. The flow behavior will be captured using a
high definition digital video camera. What we will be looking for in the flow images are
the interface shape in the evolving jet, the evolving interface angles through the pinch-off,
and any oscillations in the drops that form. An example of what we will be looking for
can be seen in Figure 1.
4
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
 = 320
 = 0
 = 40
 = 80
 = 120
 = 160
 = 200
Figure 1. Images of Pinch-Off at 1g using Laser Illumination
Reconnection Experiment
In addition to the pinch-off experiment where the dynamics of pinch-off interfaces are
examined, we wish to look at the reconnection rates. The idea of this experiment is to
generate a heterogeneous mixture of immiscible fluid particles. The fluids used will also
be mineral oil and a solution of water and glycerin. The container for these fluids will be
a cubical plexiglass box that will be sealed to prevent the existence of air bubbles that
could perturb our system. The assembly will also contain a differential volume valve to
allow for a slight change in volume due to our mixing device.
The mixing device will be used to generate a heterogeneous mixture. Once a
heterogeneous mixture has developed, we will start a stopwatch, indicating the start of the
experiment. We will then be interested in the rate of fluid separation. The stop watch will
be stopped once the liquids completely separate. Using dimensional analysis we derived
the following equation that relates the characteristic time and characteristic thickness of
heterogeneous mixture we are going to measure as a function of other known quantities:
  t t  H  H2

H
 g  a , a , r , m , a 20 , a 0 , T0 
H0
 aT0
  b  b T0 T0 T0

Where the significant parameters are:
Fixed:
a = density of fluid A
b = density of fluid B
a
5
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
b
fluid B
g = gravity force
σ = surface tension between the two liquids
Varied:
 = mixer frequency
tm = mixing time
Dependent/measured:
H0 = initial thickness of heterogeneous fluid mixture
H = measured thickness of heterogeneous mixture
tr = run time, time for the liquids to separate
In addition to obtaining the reconnection rate, we will also be examining the qualitative
“nature” of the coalescence. i.e. What do the interfaces and drop shapes look like under
different conditions? The results of this experiment will then be compared with separate
tests done at normal gravity.
3. Equipment Description
The main elements of our experimental apparatus are:
Pinch-Off Experiment:
Plexiglas Box: The experimental box will be made of ½” Plexiglas that is held
together using Weld-On 3, manufactured by the IPS Corporation. The container
will hold mineral oil and a water/glycerin mixture.
Nozzle: The jet nozzle will be made of PVC with a 1-cm exit diameter and a 4-cm
inlet diameter.
Forcing System: This forcing system, driven by a speaker, will impart a sinusoidal
oscillation on the flow to help form a repeatable pinch-off from the jet. It imposes
the oscillation onto the flow by using a piston attachment connected to the
speaker.
Pump: We will be using a 1/35 HP magnetically driven pump manufactured by
the Little Giant Pump Company. This motor will provide us with smooth,
consistent performance.
Signal Generator: A signal generator will be used as an input to the amplifier to
generate repeatable oscillations in the speaker to create starting points for pinchoff.
6
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Amplifier: The amplifier will be used to drive the speaker at controllable
amplitudes.
Tubing: The tubing used is a flexible plastic tubing that is fastened onto plastic
nipples usign hose clamps.
Needle Valve: A needle valve will be used to allow control of the mass flow rate
of fluid through the nozzle.
Speaker/Forcer
Honeycomb
Mineral Oil
Tank
Needle
Valve
Water/Glycerin
Pump
Figure 2: Pinch-Off Experimental Assembly
Reconnection Experiment:
Plexiglas Box: The box that will be made from ½” thick Plexiglas. The box will
be filled with fluid A (mineral oil) and B (water/glycerin solution). Please refer to
Figure 3 for more details. The bottom of the box will be made such that an
aluminum plate can be attached to the box. This aluminum plate will be used to
attach the box to the main frame. The top of the box will be designed in such a
way as to make it removable. The top will be attached to the flanges of the main
box and will be sealed using a rubber gasket. The top piece will also contain holes
7
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
to allow for the attachment of the mixer’s axis and an expansion piston and a
piston to allow for the internal change in volume. The inside dimension of our box
is about 10 inches3 in each direction.
Mixer: The purpose of the mixer is to create a heterogeneous mixture of the two
viscous fluids. It is driven by a pneumatic circuit and an air piston with a ten inch
stroke. The schematic of the pneumatic circuit can be seen in Figure 4.
Forcing Piston
Piston (V)
Rubber Gasket

B
Mixing Plate moving
translationally with
frequency 
Plexiglass
A
Pneumatic Circuit
Figure 3. Reconnection Box
8
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Figure 4: Schematic of Pneumatic Circuit
Attached to the cylinder is a perforated ¼ in Lexan plate with 3 4 in holes and a 50% open
area. This plate moves up and down with a frequency, , of 1Hz. After a heterogeneous
mixture has developed, the mixer is turned off and the Lexan plate automatically returns
to the top so as to not interfere with the flow.
Stopwatch: A normal stopwatch will be used to measure the mixing and running time for
each experiment.
Attachments: The attachments between and fitting for the air cylinder are made out of
flexible plastic tubing fastened with plastic fittings that properly seal.
Other:
Video Cameras: Two digital cameras will be used to capture images of both the
pinch-off and reconnection experiments.
Lights: Four fluorescent lights with their respective casings will be used.
Accelerometers: The accelerometers will be used to get real time acceleration
values corresponding to any particular moment in the experiment. The values will
be recorded by a data acquisition system.
9
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Frame: The frame will be a structure made of UnistrutTM with a cross-section of 1
5/8 in2. The outside dimensions of the frame are 61 5/8 in L x 40in H x 21in W.
This structure will support our experiments and any sharp angles will be rounded
and padded in accordance with the hazard checklist.
Entire System: The frame dimensions and the locations of the main components
inside the frame are shown in Figure 5.
Figure 5. Frame showing location of internal components (Top and front view)
10
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
6. Structural Load Analysis
Structural Design Calculations:
Component
Weight
Description
( lbs)
Dimensions
Material
Camera #1
1
5 1/4 in L x 3in W x 4in H
aluminum mounting plate
Camera #2
1
5 1/4 in L x 3in W x 4in H
aluminum mounting plate
Pinch-Off Tank
65
9in L x 9in W x 18in H
plexiglass & PVC box, aluminum mounting plate
Reconnection Tank
60
11in L x 11in W x 12 1/8 in H
plexiglass & PVC box, aluminum mounting plate
Speaker Assembly
18
8 3/16 in L x 8 3/16 in W x 20in H
aluminum mounting plate
Amplifier
14
17in L x 11in W x 5.5in H
Function Generator
5
11in L x 10in W x 4in H
Frame
170
61 1/16in L x 19in W x 40in H
steel
Pressure Circuit
3
6in L x 4in W x 6in H
plastic plate with pressure valves
Pump
6
7in L x 3.5in W x 4in H
aluminum mounting plate
Tubing, Clamps
10
N/A
plastic, aluminum
Other
Total Weight
15
368
N/A
various materials
Table 1. Weights and dimensions of components
F6
F4
F5
F2
y
x
F1
F3
Figure 6. Free body diagram of assembly
11
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Full Assembly and frame:
Figure 6 shows a free-body diagram of the frame and the main internal components. The
components shown are the components that have a weight larger than 10 lbs. The location
of these components is critical for the structural analysis. On the other hand the weight of
the rest of the components is small compared to the main component’s weight and their
location can be changed if needed.
F1=Weight of Pinch-off tank applied at its center of gravity (cg).
F2=Weight of Speaker assembly applied at its center of gravity (cg).
F3=Weight of Reconnection tank applied at its center of gravity (cg).
F4=Weight of Frame applied at its center of gravity (cg).
F5=Weight of Amplifier applied at its center of gravity (cg).
F6=Weight of Function Generator applied at its center of gravity (cg).
The location of the center of gravity of the frame with respect to the x-y coordinate
system shown in Figure 6 is:
x = 30.82 in.
y = 18.59 in. which is the location of F4.
The location of the centers of gravity of each main component with respect to the center
of gravity of the frame are shown in Table 2.
Component
Pinch-off Tank
Reconnection Tank
Speaker Assembly
Amplifier
Weight
lbs
65
60
18
14
Center of gravity
x
y
-16.6285
-6.2875
5.3125
-12.0875
-5.27
0.6125
21.1875
2.7525
Table 2. Centers of Gravity of Main Components
The components are symmetrically located with respect to the centerline of the frame
shown in the top view in Figure 5. Therefore the moments in the z direction will be
opposite and equal about the centerline.
The forces caused by the moments under the 6g loading are small compared to the forces
of the weights under the same loading. The location of the heavier components is close
enough to the center of gravity of the frame so that the moments caused by the weights
are not significant enough. The maximum force caused by the moments under the worst g
loading condition (6g) is 56 lbs upward on the bolts that attach the frame to the airplane
floor. This is well under the tensile strength of the bolts of 5000 lbs.
12
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Mid connections
Center of gravity
of frame
Center of gravity
of assembly 2
Lower
connections
Mounting
connections
Center of gravity
of assembly 1
y
x
z
Figure 7. Free- Body Diagram showing the design of the frame as well as the center
of gravity of individual assemblies.
To do the rest of the structural analysis, we decided to divide the assembly into three
different components whose weight act in their respective center of gravity (see Figure 7).
Assembly 1 includes the experiment boxes, cameras, pump and any necessary
connections. The weight shown in the table is an estimated maximum weight.
Assembly 2 includes the speaker assembly, function generator, amplifier and any
necessary connections. The weight shown in the table is an estimated maximum
weight.
Component
Frame
Assembly 1
Assembly 2
Weight
(lbs)
170
144
54
Center of Gravity
x
y
30.82
18.59
-5.98
7.543
8.372
4.875
Table 3. Centers of Gravity of Assemblies
The connections are defined as follows:
Lower connections: are the brackets between the four pieces that bolt to the floor and the
two long cross members on the bottom.
13
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Mid-connections: are the brackets that hold the side pieces to the two cross members that
hold the speaker assembly.
Mounting connections: are the corner brackets that hold the bottom of the frame together.
Assembly 1 applies an approximately uniform load to the two members on which they are
mounted. The maximum load on these members is applied under a 6g downward
loading. The load per member turns out to be 430 lbs under this g-load. For these beams,
the maximum allowable load is 1690 lbs.
Assembly 2 applies column loads to the four side members. Under the maximum 6g
loading condition, a load of 80 lbs is applied to each member. The maximum allowable
load is 2570 lbs.
The four support beams that are bolted to the aircraft floor support the entire assembly
weight under a 6g downward loading. This corresponds to a maximum load of 560 lbs
per member. For 24” members the maximum allowable load is 1690 lbs.
The connections between the members which supports assembly 1, lower connections,
can support a maximum downward load of 1000 lbs, a maximum upward load of 3000
lbs, a maximum forward or backward load of 1200 lbs, and a maximum lateral load of
1500 lbs. The maximum loads applied at these joints under the worst g-loading situations
are 215 lbs for a downward load, 72 lbs for an upward load, 320 lbs for a forward load,
and 72 pounds for a lateral load.
The connections between the members which support the assembly 2, mid connections,
can support a maximum downward load of 1000 lbs, a maximum upward load of 1500
lbs, a maximum forward or backward load of 1200 lbs, and a maximum lateral load of
1500 lbs. The maximum loads applied at these joints under the worst g-loading situations
are 80 lbs for a downward load, 27 lbs for an upward load, 120 lbs for a forward load, and
27 pounds for a lateral load.
The connections between the members that bolt to the aircraft floor, mounting
connections, can support a maximum downward load of 1000 lbs, a maximum upward
load of 1500 lbs, a maximum forward or backward load of 1500 lbs, and a maximum
lateral load of 1500 lbs. The maximum loads applied at these joints under the worst gloading situations are 280 lbs for a downward load, 95 lbs for an upward load, 420 lbs for
a forward load, and 95 pounds for a lateral load.
Note that the force applied to each connection was found by taking the component
weights attached to each member and dividing by the number of connections that hold the
members together.
Structural Analysis of Experiment Boxes:
The individual components that could fail are the Plexiglas boxes. The boxes were glued
together using Weld-On 3, manufactured by IPS Corporation. This adhesive has a
14
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
maximum strength of 3100 psi after 14 days of cure time at room temperature. The
highest stress on the seams of the boxes occurs under a 9g forward loading. The
reconnection box holds 41 lbs of fluid while the pinch-off box holds 42 lbs of fluid. For
the reconnection experiment, the maximum stress under a 9g loading is:
 
force
41 * 9

 33.5 psi
area 2 *11 * .5
The maximum stress applied to the seams of the pinch-off box is:
 
force
42 * 9

 23.6 psi
area 2 *16 * .5
These stresses are well under the maximum allowable stresses dictated by the adhesive.
Attachment of Components to Frame:
The plexiglass boxes and pump will be attached to the frame using four 3/8” bolts
through ¼” thick aluminum plates. The speaker will be mounted using a ½” thick
aluminum plate with four 3/8” bolts. A 9g forward loading leads to the maximum
bearing stress applied to the aluminum plates. Pull-out forces occur when an upward gloading in encountered. The maximum stresses and pull-out forces are summarized in the
table below, which were calculated using the following equations:
Bearing Stress 
force
area of bolt in contact with plate
Pull  Out Force 
Component
Reconnection Plate
Pinch-Off Plate
Pump Plate
Speaker Plate
force
# of bolts
Bearing Stress
1440 psi
1560 psi
144 psi
216 psi
Pull-Out Force
30 lb
32.5 lb
3 lb
9 lb
Table 4. Bearing Stresses
The bearing stress values are well below the ultimate stress of aluminum, which is 27000
psi, while the pull-out forces are well below the maximum allowable pull-out loads
supplied by the frame material manufacturer of 1000 lbs.
The amplifier, function generator, and signal analyzer will be housed in a wooden box,
with each component secured down using straps. The cameras will be mounted to plates
that will be built so that the camera height is adjustable. These components will be tested
at the University of Minnesota to ensure they can withstand the g-loading requirements.
15
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Floor Attachment:
Forward, backward, and lateral g loading conditions cause a shear stress in the floor
attachment bolts. The maximum shear stress is in the 9g forward loading case. The
thickness of the steel frame is 0.106 inches, with the entire experimental assembly
weighing 370 lb. This leads to a shear stress per bolt of:
force
370 * 9
8
  bolt 
 3.8ksi

area
2
0.375
4
The shear strength of steel is 58 ksi, which leads to a factor of safety of 15.
The maximum shear strength provided by NASA is 5000 lbs per bolt. Under a 9g
loading, our experiment applies 416.25 lbs/bolt.
An upward g loading applies a tensile force to the bolts. A 2g upward loading applies a
tensile force of 92.5 lb/bolt, well under the NASA supplied maximum value of 5000
lb/bolt.
The maximum bearing force on the frame attachment locations is under a 9g loading
condition and can be calculated as follows:
Fb 
load 370 * 9

 416.25lb
bolts
8
This is well below the maximum allowable load of the frame at a slot face, which is given
by the manufacturer as 2300 lb.
Floor Load Analysis:
The frame will be resting on 8 floor spacers. Our equipment weighs 370 pounds, which
gives a load of 46.25 lbs/spacer. This is well within the 200 lb/spacer requirement.
16
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Factors of Safety:
The corresponding factors of safety for each calculation performed above are shown in
the table below.
Load Case
Analyzed
9g forward
6g downward
2g upward
2g lateral
Location
reconnection box seam
pinch-off box seam
reconnection base plate
pinch-off base plate
pump base plate
speaker mounting plate
lower connections
mid connections
mounting connections
floor attachment shear force
floor attachment bearing force
box support beams
speaker, electronics support beams
frame supports
lower connections
mid connections
mounting connections
reconnection base plate bolts
pinch-off base plate bolts
pump base plate bolts
speaker mounting plate bolts
lower connections
mid connections
mounting connections
floor attachment bolts
lower connections
mid connections
mounting connections
Factor of
Safety
92
130
18
17
187
125
3.75
10
3.5
15
5.5
3.9
32
3
4.6
12.5
3.5
33.3
30.7
333
111
41.6
55.5
15.7
54
20.8
55.5
15.7
Table 4. Factors of Safety
6. Electrical Load Analysis
An electrical schematic showing each electrical component along with its unique wire
identifying number is shown below in Figure 8. The cord from the surge protector will
go to a 115 VAC, 60 Hz outlet. The cords for each electrical device were included with
the equipment when it was purchased and so they are adequate for carrying the current
needed to power each device. The gauge size and current carried by each wire is shown
below in Table 5. The surge protector we are using has the master kill switch for our
system.
17
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Camera #1
Camera #2
Function
Generator
Amplifier
Pump
1
6
Light #1
2
7
Surge Protector with
Kill Switch
3
8
Light #2
Light #3
4
9
Light #4
5
To aircraft power distribution
panel
Figure 8: Electrical schematic.
Equipment
Cameras
Function Generator
Amplifier
Pump
Lights
Wire Gauge Size
18
18
18
Current Carried
0.04 A Each
0.75 A
1.3 A
1.1 A
0.275 A Each
Table 5: Listing of equipment with wire gauge size and current carried.
A summary of the electrical load analysis is given below in Table 6. All of our electrical
equipment will be plugged into a surge protector that is equipped with a kill switch.
In the case of a power loss, our amplifier, pump, and lights would stop operating.
However, this is in no way an unsafe configuration. Our digital video cameras will be
equipped with batteries, which provide back-up power. This will allow the cameras to
operate during a power loss, thus keeping all the settings on the cameras from changing to
default power-up settings.
Power Source Details
Load Analysis
Name: Power Cord A
Voltage: 115 VAC, 60 Hz
Wire Gauge: 12
Cameras #1 & #2: 0.04 A Each
Lights #1 - #4: 0.275 A Each
Function Generator: 0.75 A
Amplifier: 1.3 A
Pump: 1.1 A
Max Outlet Current: 20 A
Total Current Draw: 4.33 Amps
Table 6. Electrical load table.
7. Pressure Vessel Certification
18
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
2
6
1
9
7
8
10
9
8
11
3 5
11
Figure 9. Schematic of Pressure System (Schematic not drawn to scale)
Table 7 shows all the components along with their characteristics. The MAWP of the
pneumatic circuit system is 150 psi. The pneumatic circuit and the piping system were
built and tested at the University of Minnesota-Twin Cities. They were both built using
appropriate fittings to prevent leakage at joints and excessive loads and stresses. The
individual components were calibrated and tested at the University of Minnesota.
19
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Table 7. Pressure system components
Regulator
Setting
(psi)
Built By
Cert. Test /
Calib. Date
Proof Test –
Certified By
N/A
RGO-NASA
N/A
N/A
N/A
100
Pending
Pending
Pending
100
N/A
50 –75
Air
Engineering
and Supply
Nov- Dec
2000
U of M
Pressure
Relief Valve
200
150
N/A
Nov- Dec
2000
U of M
5
Pressure
Gauge
100
110
50
Air
Engineering
and Supply
Air
Engineering
and Supply
Nov- Dec
2000
U of M
6
Air Cylinder
100
N/A
N/A
Clippard
minimatic
Nov- Dec
2000
U of M
7
Four-Way
Valve
150
N/A
N/A
Clippard
minimatic
Nov- Dec
2000
U of M
8
Three-Way
Valve
150
N/A
N/A
Clippard
minimatic
Nov- Dec
2000
U of M
9
Pneumatic
Circuit Board
110
N/A
N/A
Clippard
minimatic
Nov- Dec
2000
U of M
10
Experiment
Box
N/A
N/A
N/A
N/A
N/A
N/A
11
On-Off toggle
valve
N/A
N/A
N/A
N/A
N/A
N/A
Schematic
Reference
#
Component
Description
MAWP
(psi)
Relief Valve
Setting (psi)
1
Breathing-air
K bottle
1500
N/A
2
Regulator
3000
3
Regulator
4
20
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
8. Laser Certification
No lasers will be used in our experiment
9. Parabola Details and Crew Assistance
The in flight test procedures will be made as automated and simple as possible so that the
experiments can be run easily under the constantly changing gravity environment. The
step-by-step process once we are in the air and able to move about the cabin is:
1. Supply power to the amplifier and pump. This will begin the closed loop circulation
of fluids in the pinch-off experiment that will run continuously during the flight. Also,
open the compressed air regulator to supply compressed air to our pneumatic circuit.
2. Turn on the digital video cameras. With the exception of having to change tapes, the
cameras will be running continuously. Start taking acceleration data, every 30
seconds.
3. Right before zero gravity conditions, start the mixing of the two fluids in the
reconnection experiment. This will last approximately 5-10 seconds.
4. Once zero gravity is reached, start the stopwatch for the reconnection experiment and
stop when complete separation has occurred.
5. Repeat steps 3 & 4 for other parabolas. However, there will be slight variations in the
reconnection experiment between parabolas. See Table 8.
6. After all of the parabolas are completed, turn off the power to the instruments and
make sure secure for landing.
Parabola
Time to Leave
Mixer On
Zoom Position
5 sec.
5 sec.
2x2 in square
8x8 in square
10 sec.
10 sec.
8x8 in square
2x2 in square
Day 1
1-15
16-32
Day 2
1-17
17-32
Table 8. Test Matrix for Reconnection Experiment
10. Free Float Requirements
There are no free float experiments.
21
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
11. Institutional Review Board
None needed.
12. Hazard Analysis
A. Hazard Source Checklist
1
2
3
NA
NA
NA
4
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
5
6
NA
NA
NA
NA
Flammable/combustible material, fluid (liquid, vapor, or gas)
Toxic/noxious/corrosive/hot/cold material, fluid (liquid, vapor, or gas)
High pressure system (static or dynamic)
Evacuated container
Frangible Material
Stress corrosion susceptible material
Inadequate structural design (e.g. low safety factor)
High intensity light sources (including laser)
Ionizing/electromagnetic radiation
Rotating device
Extendible/deployable/articulating experiment element (collision)
Stowage restraint failure
Stored energy device (e.g. mechanical spring under compression)
Vacuum vent failure (i.e. Loss of pressure atmosphere)
Heat transfer (habitable area over-temperature)
Over-temperature explosive rupture (including electrical battery)
High/low touch temperature
Hardware cooling/heating loss (i.e. loss of thermal control)
Pyrotechnic/explosive device
Propulsion system (pressurized gas or liquid/solid propellant)
High acoustic noise level
Toxic off-gassing material
Mercury/mercury compound
Other JSC 11123, Section 3.8 hazardous material
Organic/microbiological (pathogenic) contamination source
Sharp corner/edge/protrusion/protuberance
Flammable/combustible material, fluid ignition source (i.e. short circuit; undersized wiring/fuse/circuit breaker)
High Voltage (electrical shock)
High static electrical discharge producer
Software error
Carcinogenic material
22
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
B. Detailed Hazard Descriptions
Hazard Number:
1
Title: Flammable/combustible material, fluid (liquid, vapor, or gas)
Hazard Description: Fire
Hazard Cause(s):
Flammable chemical: glycerin
Hazard Controls(s): The experiments environment and the liquids in the experiment
boxes will be at room temperature. No sources of fire or heat will
be used in the experiment
Hazard Number:
1
Title: Flammable/combustible material, fluid (liquid, vapor, or gas)
Hazard Description: Fire
Hazard Cause(s):
Flammable chemical: mineral oil
Hazard Controls(s): The experiments environment and the liquids in the experiment
boxes will be at room temperature. No sources of fire or heat will
be used in the experiment
Hazard Number:
2
Title: Toxic/noxious/corrosive/hot/cold material, fluid (liquid, vapor, or gas)
Hazard Description: Exposure to toxic chemical: skin and eye contact.
Hazard Cause(s):
Toxic chemical: glycerin
Hazard Controls(s): The glycerin will be diluted as a water-glycerin mixture (50/50),
which will be mixed on ground.
The experiments boxes are designed as leak-free systems. For the
reconnection experiment box, a cylinder to allow for a change in
volume will be used. Also, the air cylinder used in the pressure
system is designed to work as a leak free system.
Hazard Number:
3
Title: High pressure system (static or dynamic)
Hazard Description: Over pressurization of the system
23
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Hazard Cause(s):
Compressed air tank pressurized at 2200 psig used in a pressure
system designed for a maximum of 100 psig.
Hazard Controls(s): Redundant pressure relief valves, calibrated at 200 psi, will be used
in the pressure system.
Hazard Number:
4
Title: Sharp corner/edge/protrusion/protuberance
Hazard Description: Injuries from sharp corners of the frame.
Hazard Cause(s):
Sharp corners and edges of the frame
Hazard Controls(s): Foam padding will be used on all sharp edges of the frame
and experiments.
Hazard Number:
5
Title: Flammable/combustible material, fluid ignition source (i.e. short circuit; undersized wiring/fuse/circuit breaker)
Hazard Description: Fire and combustion of chemicals
Hazard Cause(s):
Short circuit
Hazard Controls(s): A surge protector will be used, and it will be located away
from the experiments boxes.
13. Tool Requirements
A minimum number of tools required to assemble our structure will be brought down.
These tools will be kept in a locked, marked toolbox and a location assigned to us be the
Reduced Gravity Office.
14. Photo Requirements
1) No still photographer will be required.
2) No still photographer will be required.
3) No s-band downlink is required
4) No camera poles will be required.
24
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
15. Aircraft Loading
1. A fork-lift will be needed to load the experiment into the airplane.
2. Eight handles will be placed on the assembly frame, thus limiting the load per
handle to 46.25lbs.
load _ per _ handle 
370lbs
 46.25lbs
8
3. Load on aircraft floor:
Total weight of the assembly: 370lbs.
Base plate area of the assembly: 2400 in2 = 16.67 ft2
load _ on _ aircraft _ floor 
370lbs
 22.2lbs / ft 2
2
16.67 ft
16. Ground Support Requirements
1) Type of power required: 115 V AC, 60 Hz
2) Pressurized air required: Breathing-air K bottles (volume 233 ft3 at 2200 psig) (2
bottles) (x2)
3) Chemicals that will be stored are:
- Glycerin-Water mixture (50/50) – 12 gallons
- Mineral Oil – 10 gallons
These chemicals have to be stored in a well-ventilated area with no direct
sunlight. The containers will be kept closed until used.
4) A forklift for loading our frame onto the plane will be required.
5) No access to building 993 during hours other than normal business hours will be
requested.
6) No general tool requests or special ground handling will be requested.
17. Hazardous Materials
The fluids that will be used in our experiments are:
- Glycerin/Water mixture (50/50)
- Mineral Oil
25
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Glycerin (Glycon G-100)
This chemical is considered a flammable and toxic material. MSDS form is attached. The
glycerin will be used in a glycerin/water mixture of 50/50 by volume. The amounts of this
mixture that will be used are the following:
Reconnection experiment:
Pinch-off experiment:
2.5 gallons
2.0 gallons
Total amount of mixture
that will be taken to the
Reduced Gravity Office:
10 gallons (Two 5-gallon pails)
It will be properly contained for transportation, handling, and storage. The containers will
be closed until used. When filling the experiments boxes protective gloves will be used to
avoid skin contact. After the experiments boxes are filled, they will be sealed, thus
preventing further contact. The experiments boxes are designed to prevent leaking.
Mineral Oil (White Mineral Oil)
This chemical is considered a flammable material. MSDS form is attached. The amounts
of mineral oil that will be used are the following:
Reconnection experiment:
Pinch-off experiment:
2.5 gallons
3.0 gallons
Total amount of mixture
that will be taken to the
Reduced Gravity Office:
10 gallons (Two 5-gallon pails)
It will be properly contained for transportation, handling, and storage. The containers will
be closed until used. After the experiments boxes are filled, they will be sealed, thus
preventing further contact. The experiments boxes are designed to prevent leaking.
No provisions for dumping and purging will be required for any of the boxes. No
chemicals will be released.
18. Material Safety Data Sheets (MSDS)
Please see attached documents.
26
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
19. Experiment Procedures Documentation
Equipment Shipment to Ellington Field
The equipment will be shipped to and from Ellington Field via United Parcel Services
(UPS). The package is scheduled to arrive on February 5th.
Ground Operations
Only a minimal amount of work needs to be done on the ground. The majority of that
work is going to be assembling the equipment and confirming it’s calibrated and working
properly. Things we will need are noted in the ground support requirements section and in
the quick reference sheet.
Loading
A forklift will be required to load the assembly onto the airplane. Once it is on, we will
use the attached handles to move it to our designated location.
Preflight
The two fluid containers will be assembled at the University of Minnesota prior to arrival
at Ellington Field. The frame will need to be assembled in at Ellington Field however.
The Reduced Gravity Office (RGO) will not need to supply any tools for the assembly of
the frame. The two cameras and the rest of the equipment will be secured to the frame
using appropriate hardware. Prior to loading the frame, the entire system will be
examined for leakage, and electrical malfunctions. After such testing, we will perform
sample experiments to make sure the experiment is working properly.
Take-off/Landing
There are nothing to note here. There are no take-off/landing procedures.
In-flight & Postflight
The checklist shown below, Table 9, will be used for each flight.
27
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
Pre-Flight
Person 1 Person 2
Fasten frame securely
Plug equipment in
Plug in surge protector
Check pressure system
Focus cameras
Turn power off prior to take-off
In-Flight
Turn power on
Pressurize pneumatic circuit
Focus cameras
Acceleration Readings
Stopwatch
Post-Flight
Turn power off prior to landing
Remove frame
Table 9. Procedural Checklist
In the case of an electrical emergency in the flight, the first procedure is to hit the kill
switch on the surge protector.
There are no special procedures in readying the equipment for the next day’s flight.
Before the next day’s flight a couple of minutes will be taken to assure that everything is
still running smoothly.
Offloading
A forklift will also be required to offload our apparatus.
UPS will also be used to ship our equipment back to the university.
28
Pinch-Off and Reconnection Proposal; University of Minnesota- Twin Cities
20. Bibliography
Longmire, E.K., Lowengrub, J.S., and Gefroh, D.L. “A Comparison of Experiments and
Simulations and Pinch-Off in Round Jets,” ASME FEDSM99-711, 3rd
ASME/JSME Joint Fluids Engineering Conference, San Francisco
Longmire, E.K., and Lowengrub, J.S. “Pinch-Off in Liquid/Liquid Jets:
Experiments and Simulations,” 17th Symposium on Energy Engineering Sciences,
Argonne, IL, 1999
Gefroh, D.L., and Longmire, E.K. “Study of Vorticity Evolution in Liquid Jet Pinch-Off
Process,” Report 1998-3, Dept. of Aerospace Engineering & Mechanics,
University of Minnesota
UNISTRUT Northern, “General Engineering Catalog,” North American Edition No. 12
29