mechanical engineering rowan university 201 mullica hill rd. glassboro, nj 08028
DESCRIPTION
36 th Annual Frontiers in Education Conference San Diego, CA, Oct. 28-31, 2006. THIS IS ROCKET SCIENCE: DEVELOPMENT AND TESTING OF A HYBRID ROCKET MOTOR IN A ROCKET PROPULSION COURSE. Anthony J. Marchese. Mechanical Engineering Rowan University 201 Mullica Hill Rd. Glassboro, NJ 08028. - PowerPoint PPT PresentationTRANSCRIPT
THIS IS ROCKET SCIENCE: DEVELOPMENT AND TESTING OF A HYBRID ROCKET MOTOR IN A ROCKET PROPULSION COURSE
Mechanical EngineeringRowan University
201 Mullica Hill Rd.Glassboro, NJ 08028
http://users.rowan.edu/~marchese
36th Annual Frontiers in Education ConferenceSan Diego, CA, Oct. 28-31, 2006
Anthony J. Marchese
On October 4, 2004, SpaceShipOne became the first private manned spacecraft to exceed an altitude of 328,000 feet twice within a 2 week period, thereby claiming the $10 million Ansari X-Prize.
SpaceShipOne was powered by a hybrid rocket motor (liquid N2O, solid polymer fuel)
N2O
solid fuel
Private Sector Opportunities in Space Exploration
Motivation for the Hybrid Rocket Motor Project
Objectives, Design Parameters and Constraints
The Hybrid Rocket Motor Design Project
Objectives of the semester design project: Design, build and test a hybrid rocket motor.
Develop a theoretical model that predicts the performance of the hybrid rocket motor as a function of time.
Compare measured performance with theoretical model.
Constraints: Oxidizer must be gaseous oxygen (GOX)
Maximum Chamber Pressure: 115 psia, Ambient Pressure: 14.7 psia
Maximum GOX flow rate: 500 SLPM
Minimum initial thrust: 5 lbf
Fuel grain outer diameter = 1.175 in
Maximum Fuel Grain Length = 12 in
Fuel: HTPB, HTPB/AL, PMMA, PE, UHMW or paraffin
GOX
HTPB/Al graphitealuminum
Theoretical Model: This is Rocket Science
Hybrid Rocket Motor Design Project
n
p
of tA
matr
)()(
n
p
obff tA
matAtm
)()()(
n
p
obfo
tc tA
matAm
A
CtP
)()(
*)(
Ab
solid fuelAp
Liquid oxidizer omfr
fm
AtAe
Pc
m
Tc, Xi,
t
e
cc
eF A
A
P
P
P
PC
1
c
e1)-2(
1
P
P-1
1-
2
1
2
FCCmF *
o
F
o
SP g
CC
dtmg
FdtI
*
Fuel Regression Rate
Fuel Mass Flow Rate
Chamber Pressure
Thrust Coefficient
Thrust
Specific Impulse
Characteristic Exhaust Velocity
f
o
m
mCC
**
Specific Heat Ratio
f
o
m
m
Theoretical Model Results
Hybrid Rocket Motor Design Project
The detailed analytical model was used to predict the variation in fuel flow rate, O/F ratio, chamber pressure, thrust and specific impulse (Isp)
with time.
Ab
solid fuelAp
Liquid oxidizer omfr
fm
AtAe
Pc
m
Tc, Xi,
Ab
solid fuelAp
Liquid oxidizer omfr
fm
AtAe
Pc
m
Tc, Xi,
time (s)
0 5 10 15 20 25 30
Spe
cific
Im
puls
e [s
]
175
180
185
190
195
200
time (s)
0 5 10 15 20 25 30
Thr
ust
[lbf]
4
5
6
7
8
time (s)
0 5 10 15 20 25 30
Cha
mbe
r P
ress
ure
[psi
a]
85
90
95
100
105
110
The theoretical hybrid rocket motor model was also used iteratively optimize their final design to choose the following parameters:
fuel grain length
port diameter
throat diameter
nozzle area ratio
nozzle exit diameter
Concept Design and Parametric Design
The Hybrid Rocket Motor Design Project
Final design drawings were generated for the combustion chamber and the supersonic nozzle using Solid Works.
GOX
HTPB/Al graphitealuminum
L
dp dt de
Fabrication
The Hybrid Rocket Motor Design Project
Combustion chambers were fabricated from aluminum round stock using manual lathes
Supersonic nozzles were fabricated from graphite using a CNC turning center
Fuel Formulation
The Hybrid Rocket Motor Design Project
Hydroxyl Terminated Polybutadiene (HTPB) was formulated, mixed with aluminum particles and cured.
Other fuels such as PMMA, HDPE and UHMW were machined from solid round stock
Mass flow rate was measured and controlled using a Teledyne Hastings HFC203 Mass Flow Controller.
Thrust was measured using an Omega LC101-25 load cell.
Chamber pressure was measured using an Omega Pressure Transducer.
Development of the Hybrid Rocket Motor Test Stand
The Hybrid Rocket Motor Design Project
Thrust Chamber
Nozzle
Load Cell
Igniters
Linear Bearing
Pressure Transducer
Solenoid Valve GOXMass FlowController
The Objective: Deliver a hybrid rocket motor test stand capable of measuring thrust (0-10 lb), chamber pressure (0-250 psig), oxygen mass flow rate (0-500 SLPM)
The Team: Two senior mechanical engineering students, one junior mechanical engineering student and one senior electrical engineering student.
The ignition system consists of dual automotive spark plugs which are energized using an ETP 300ST solid state induction coil
Development of the Hybrid Rocket Motor Test Stand
The Hybrid Rocket Motor Design Project
Igniters
Pressure Transducer
Flow Controller Solenoid Valve
Check Valve
Development of the Hybrid Rocket Motor Test Stand
The Hybrid Rocket Motor Design Project
Load CellLinear Bearing
Data Acquisition
The Hybrid Rocket Motor Design Project
Data acquired included:
instantaneous chamber pressure,
thrust,
oxygen mass flow rate and
high speed dynamic chamber pressure
The data were acquired using an Agilent 34970A Data Acquisition Unit with GPIB interface and an HP 54645D digital storage oscilloscope
With these data, each team was able to measure specific impulse (Isp), characteristic exhaust velocity (C*) and thrust coefficient (CF) and compare these measurements to their analytical models.
Is this valve open?…first test firing of the Hybrid Rocket Motor
Test stand.
The Hybrid Rocket Motor Design Project
Test Firing (HTPB/AL/GOX)
The Hybrid Rocket Motor Design Project
Experimental Results
The Hybrid Rocket Motor Design Project
Time [s]
0 5 10 15 20 25
Thr
ust
[lb]
0
2
4
6
8
10
F (Calculated)F (Measured)
Cha
mbe
r P
ress
ure
[psi
g)
0
20
40
60
80
100
Pc (Calculated)
Pc (Measured)
The analytical models reproduced the experimental data reasonably well.
When the variation in actual oxygen mass flow rate was taken into account, analytical results matched the experiments very well!
Conclusions
The Hybrid Rocket Motor Design Project
At the beginning of the semester, students showed very little awareness of the space program and its significance (both historic and contemporary).
This condition is surprising to the generation who grew up wanting to be astronauts.
The hybrid rocket design project was successful in introducing a new generation of students to rocket science.
The hybrid rocket motors were inexpensive, relatively easy to build and safe.
The hybrid rocket motor test stand was an effective junior/senior level design project. Total project cost was approximately $2000.
The test stand is now being used for scholarly pursuits.