THIS IS ROCKET SCIENCE: DEVELOPMENT AND TESTING OF A HYBRID ROCKET MOTOR IN A ROCKET PROPULSION COURSE

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THIS IS ROCKET SCIENCE DEVELOPMENT AND TESTING
OF A HYBRID ROCKET MOTOR IN A ROCKET PROPULSION
COURSE
36th Annual Frontiers in Education Conference San
Diego, CA, Oct. 28-31, 2006
Anthony J. Marchese
Mechanical Engineering Rowan University 201
Mullica Hill Rd. Glassboro, NJ 08028
http//users.rowan.edu/marchese
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Overview
This is Rocket Science The Hybrid Rocket Motor
Project

• Motivation for a project based learning
  experience in rocket propulsion
• Context Description of the rocket propulsion
  course
• Description of the project objectives,
  requirements and constraints
• Development of the analytical model
• Design and fabrication of the hardware
• Development of the hybrid rocket motor test stand
• The Engineering Clinic
• Test results
• On going tests

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Course Objectives
Introduction to Rocket Propulsion (ME 412)

• Rocket propulsion draws upon the fundamental
  concepts of thermodynamics, chemistry, fluid
  mechanics and heat transfer to design propulsion
  systems. At the conclusion of the course, each
  student will be able to
• Analyze the performance of an ideal rocket
  engine.
• Select propellants and choose a rocket propulsion
  system based on mission requirements.
• Perform thermochemical calculations to determine
  the rocket chamber temperature and chemical
  composition for any propellant combination.
• Design a liquid propellant rocket engine by
  considering the propellant combination,
  combustion chamber, injector, igniter, nozzle,
  heat transfer and cooling characteristics.
• Design a solid propellant rocket motor based on
  the propellant combination, burning rate laws and
  grain design.
• Design a hybrid rocket motor based on the
  propellant combination, burning rate laws and
  grain design.
• Build and test a 10 lbf thrust hybrid rocket
  motor.   Measure specific impulse, characteristic
  exhaust velocity, thrust coefficient and compare
  to theoretical calculations.

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Motivation for the Hybrid Rocket Motor Project
Private Sector Opportunities in Space Exploration

• 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
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The Hybrid Rocket Motor Design Project
Objectives, Design Parameters and Constraints

• 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

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Hybrid Rocket Motor Design Project
Theoretical Model This is Rocket Science
Fuel Regression Rate
Thrust Coefficient
Fuel Mass Flow Rate
Thrust
Specific Impulse
Chamber Pressure
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Hybrid Rocket Motors
Thermochemical Model This is Rocket Science
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Hybrid Rocket Motor Design Project
Theoretical Model Results
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.
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The Hybrid Rocket Motor Design Project
Concept Design and Parametric Design

• 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

L
dp
dt
de
Final design drawings were generated for the
combustion chamber and the supersonic nozzle
using Solid Works.
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The Hybrid Rocket Motor Design Project
Fabrication
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The Hybrid Rocket Motor Design Project
Fuel Formulation
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The Hybrid Rocket Motor Design Project
Development of the Hybrid Rocket Motor Test Stand
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.
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
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The Hybrid Rocket Motor Design Project
Development of the Hybrid Rocket Motor Test Stand
Solenoid Valve
Flow Controller
Igniters
Pressure Transducer
Check Valve
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The Hybrid Rocket Motor Design Project
Development of the Hybrid Rocket Motor Test Stand
Load Cell
Linear Bearing
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The Hybrid Rocket Motor Design Project
Data Acquisition

• 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.
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The Hybrid Rocket Motor Design Project
Test Firing (HTPB/20 AL/GOX)
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The Hybrid Rocket Motor Design Project
Test Firing (Big Red)
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The Hybrid Rocket Motor Design Project
Experimental Results
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!
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The Hybrid Rocket Motor Design Project
Ongoing Work
The system is now being used for a research
project on the effect of fuel type on combustion
instability of hybrid rocket motors.
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The Hybrid Rocket Motor Design Project
Conclusions

• 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.

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The Hybrid Rocket Motor Design Project
Is this valve open?