1. 0
0.5
1
1.5
2
2.5
3
0
20
40
60
80
100
Mass
Flow
Rate
[g/min]
Time
[min]
Trial
1
Trial
2
Trial
3
Prototype
I
and
II
Tes:ng
A
total
of
three
prototypes
were
designed,
printed,
and
tested
(Figure
2).
The
purpose
of
prototype
I
was
to
validate
the
concept
of
the
nested
shell
design
and
to
test
the
limitaFons
of
a
composite
pressure
vessel
printed
using
ABSplus.
For
prototype
II,
the
purpose
was
to
test
the
design
changes
made
and
to
pracFce
recording
boil
off
mass
flow
rate.
Prototype
I
Problems
» Since
all
of
the
caps
were
printed
separately,
ABS
cement
was
used
to
aNach
each
cap
to
the
main
shell.
Due
to
the
cap
thinness,
the
cement
would
leak
into
the
sides
of
the
shell,
clogging
up
the
vapor
passage.
» Cracking
was
audible
when
LN2
was
poured
into
the
tank
and
vapor
was
seen
seeping
out
of
the
boNom,
signifying
internal
failures.
Prototype
I
Conclusions
» Cap
and
shell
thickness
increase
were
necessary.
To
facilitate
assembly,
the
boNom
caps
would
be
printed
aNached
to
the
shell
in
prototype
II.
Prototype
II
Problems
» Once
again,
vapor
passage
blockage
from
the
ABS
cement.
» Since
the
boNom
was
now
part
of
the
shell,
there
were
concerns
that
the
support
material
needed
for
the
second
vapor
hole
would
not
dissolve
enFrely.
Prototype
Conclusions
» The
usage
of
rubber
O-­‐rings
to
make
a
leak
free
seal
instead
of
cement
was
decided
on.
The
number
of
vapor
holes
for
the
second
layer
was
increased
from
one
to
seven
to
prevent
support
material
blockage.
Methods
Two
steps
are
required
in
order
to
validate
our
tank
design:
an
iteraFve
design
process
and
a
tesFng
process
of
prototypes.
Using
SolidWorks
2013
Student
EdiFon,
iniFal
designs
of
the
tank
were
created.
Once
specific
details,
such
as
wall
thickness
or
cap
design,
were
agreed
upon
the
SolidWorks
file
was
saved
as
an
STL
file
and
was
then
to
be
printed
using
the
uPrint
SE
by
Stratasys.
Once
prinFng
was
complete,
prototypes
composed
of
ABSplus
and
lined
with
polystyrene
were
then
tested
using
liquid
nitrogen
(LN2)
and
their
boil
off
mass
flow
rate
calculated.
The
addiFonal
use
of
Mylar
as
an
insulaFon
was
also
tested.
Prototype
Design
of
a
Type
IV
Hydrogen
Pressure
Vessel
with
Vapor
Cooled
Shielding
Gina
Georgadarellis1,2,
Patrick
Adam2,
and
Dr.
Jacob
Leachman2
1University
of
MassachuseNs
Amherst;
2Mechanical
Engineering;
Washington
State
University
Acknowledgements
This
work
was
supported
by
the
NaFonal
Science
FoundaFon’s
REU
program
under
grant
number
EEC-­‐1157094.
Introduc:on
The
uFlizaFon
of
hydrogen
as
a
fuel
source
requires
solving
the
issue
of
containment.
Hydrogen
stores
2.8
Fmes
more
energy
per
weight
than
gasoline
but
more
than
three
Fmes
as
much
volume
is
typically
required,
making
it
difficult
for
gasoline-­‐powered
vehicles
to
convert
to
hydrogen
power.
To
resolve
this
issue,
hydrogen
can
be
liquefied
to
increase
the
density
to
two
Fmes
that
of
room
temperature
gas
at
700
bar
(10,000
psi).
The
new
issue
created
with
the
use
of
liquid
hydrogen
is
the
low
temperature
(-­‐422°F,
21K)
needed
for
hydrogen
to
maintain
the
liquid
state.
A
type
IV
pressure
vessel
made
of
polymeric
liner
and
wrapped
in
a
fiber-­‐
resin
composite
may
be
used
to
meet
such
requirements.
Hydrogen
and
Pressure
Vessels
Table
1
below
compares
and
shows
five
types
of
pressure
vessels2.
Each
of
the
five
types
of
pressure
vessels
can
be
used
and
the
choice
of
storage
depends
on
the
applicaFon.
When
cost
needs
to
be
minimized,
hydrogen
is
stored
in
type
I
tanks
with
pressures
ranging
from
150
to
300
bars.
In
regards
to
staFonary
purposes,
when
higher
pressures
are
desired
type
II
tanks
are
typically
chosen.
When
weight
is
an
issue
and
cost
may
be
disregarded,
type
III
and
type
IV
vessels
are
preferred,
especially
for
portable
applicaFons.
References
1. Naval
Research
Laboratory.
"Ion
Tiger
Fuel
Cell
Unmanned
Air
Vehicle
Completes
23-­‐
hour
Flight."
ScienceDaily.
ScienceDaily,
15
October
2009.
2. Barthélémy,
Hervé.
“Hydrogen
Storage
–
Industrial
ProspecFves.”
Interna+onal
Journal
of
Hydrogen
Energy
37.22
(2012):
17364–17372.
Web.
13
June
2014.
Results
and
Conclusions
We
compared
the
percent
differences
of
the
integrated
average
boil
off
mass
flow
rates
between
the
sole
use
of
polystyrene
as
an
insulaFon
and
the
different
combinaFons
of
Mylar
(Table
2).
Though
the
graphs
look
similar,
the
percent
differences
show
that
the
different
combinaFons
of
polystyrene
and
Mylar
each
have
an
effect
on
the
mass
flow
rate.
Our
design
of
a
type
IV
pressure
vessel
with
vapor
cooled
shielding
successfully
holds
and
insulates
liquids
at
cryogenic
temperatures.
In
the
future,
experimenFng
with
different
types
of
insulaFon
as
well
materials
used
for
the
tank
may
be
beneficial.
Mo:va:on
Hydrogen
fuel
use
is
not
a
new
idea.
Liquid
hydrogen-­‐powered
vehicles
running
on
high-­‐power
fuel
cell
propulsion
systems
(Ion
Tiger
by
the
U.S
Naval
Research
Laboratory)
and
propeller-­‐driven
internal
combusFon
engines
(Phantom
Eye
by
Boeing)
are
in
use.
AddiFonally,
Washington
State
University
Unmanned
Aerial
Systems
is
in
the
process
of
building
Genii,
the
first
university
demonstrated
liquid
hydrogen-­‐powered
unmanned
aerial
system
for
long
endurance
missions
(Figure
1).
A
type
IV
hydrogen
pressure
vessel
with
vapor
cooled
shielding,
however,
has
never
been
done
before.
With
our
vessel,
the
goal
is
to
design
a
tank
that
has
excellent
insulaFon,
has
a
built
in
heat
exchanger,
and
can
contain
liquid
hydrogen
while
withstanding
the
cryogenic
temperatures
associated
with
it
0
0.5
1
1.5
2
2.5
3
0
20
40
60
80
Mass
Flow
Rate
[g/min]
Time
[min]
Trial
1
Trial
2
Trial
3
0
0.5
1
1.5
2
2.5
3
3.5
0
10
20
30
40
50
60
70
Mass
Flow
Rate
[g/min]
Time
[min]
Trial
1
Trial
2
Trial
3
Table
1:
Informa:on
on
Pressure
Vessels
Type
Image*
Material
Used
Main
Features
I
Metal
tank
with
no
liner
Pressure
limit:
300
bars
Excellent
cost
performance
Poor
weight
performance
II
Thick
metallic
liner
hoop
wrapped
with
a
fiber-­‐resin
composite
No
pressure
limit
Good
cost
performance
Neutral
weight
performance
III
Metallic
liner
fully-­‐
wrapped
with
a
fiber-­‐
resin
composite
Usable
for
pressures
less
than
350
bars
Poor
cost
performance
Good
weight
performance
IV
Polymeric
liner
fully-­‐
wrapped
with
a
fiber-­‐
resin
composite
Usable
for
pressures
less
than
350
bars
Poor
cost
performance
Good
weight
performance
V
Composite
tank
with
no
liner
Can
be
made
into
conformal
shapes
more
easily
*The
type
V
image
is
adapted
from
hNp://www.compositesworld.com/
Prototype
III
Tes:ng
Using
the
Cole-­‐Parmer
Symmetry
IS
Compact
Industrial
Bench
Scale,
Omega
RH820
Humidity
Temperature
Handheld
Meter,
and
LN2,
the
boil
off
mass
flow
rate
was
recorded
for
prototype
III.
The
experiment
was
setup
so
that
the
mass
of
the
vessel,
which
contained
LN2,
was
recorded
every
five
minutes
unFl
the
mass
no
longer
changed
(Figure
3).
This
process
was
repeated
three
Fmes
for
each
different
combinaFon
of
insulaFon
and
boil
off
mass
flow
rate
was
then
calculated
using
excel.
The
results
from
the
experiment
are
shown
below
(Figure
4).
For
each
trial,
the
general
shape
of
the
graph
was
similar.
The
mass
flow
rate
peaked
at
the
very
beginning,
steadily
decreased,
and
then
reached
zero
at
the
very
end
arer
minor
oscillaFons
in
the
mass
flow
rate.
a)
Overall
Experiment
Setup
b)
Temperature
Meter
Placement
Figure
3:
Prototype
III
Boil
Off
Mass
Flow
Rate
TesFng
Figure
2:
Going
counterclockwise
from
the
top
ler
corner,
shown
above
are
pictures
of
prototype
components,
the
aerial
view
of
the
shell,
and
CAD
drawings
for
(a)
prototype
I,
(b)
prototype
II,
and
(c)
prototype
III.
a)
b)
c)
Figure
4:
A
plot
of
the
boil
off
mass
flow
rate
vs.
Fme
is
shown
for
prototype
III
when
(a)
polystyrene,
(b)
polystyrene
with
an
outer
layer
of
Mylar,
(c)
polystyrene
with
an
inner
layer
of
Mylar,
and
(d)
polystyrene
with
both
an
outer
and
inner
layer
of
Mylar
were
used
for
insulaFon.
a)
b)
c)
d)
Table
2:
Integrated
Average
Mass
Flow
Rate
and
Percent
Difference
from
Polystyrene
of
Prototype
III
Integrated
Average
Mass
Flow
Rate
[g/min]
Percent
Difference
from
Polystyrene
Trial
1
Trial
2
Trial
3
Average
Trial
1
Trial
2
Trial
3
Average
Polystyrene
0.6031
0.6293
0.4895
0.57396
-­‐
-­‐
-­‐
-­‐
Polystyrene
and
Outer
Mylar
0.5693
0.6067
0.5967
0.5909
5.7563
3.6677
19.7383
9.7208
Polystyrene
and
Inner
Mylar
0.7683
0.7031
0.7046
0.7253
24.1002
11.0692
36.0344
23.7346
Polystyrene,
Outer
Mylar,
and
Inner
Mylar
0.7067
0.5708
0.8746
0.7173
15.8183
9.7486
56.4613
27.3428
0
0.5
1
1.5
2
2.5
3
3.5
0
20
40
60
80
Mass
Flow
Rate
[g/min]
Time
[min]
Trial
1
Trial
2
Trial
3
Figure
1:
Examples
of
vehicles
that
uFlize
liquid
hydrogen
use
as
fuel.
(a)
Ion
Tiger
and
its
fuel
cell1
(b)
Phantom
Eye
(c)
Genii
UAS