1. 3D-Printed Hybrid Rocket Fuel Grains
Fused Layer ABS Rocketry Experiment (F.L.A.R.E)
Amy Besio
Jonathan Benson
Richard Horta
John Seligson
Josh Rou
Faculty/Technical Advisor:
Justin Karl, Ph.D.
2. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Amy Besio-Project Manager/Propulsion System Design 1
• Mission Statement
• To design, fabricate, and test 3D printed fuel grains
to optimize hybrid rocket performance
characteristics
Design Objectives
• Design Specifications
• Oxidizer/Fuel
• 𝑁2 𝑂/𝐴𝐵𝑆
• Burn Time: 5s
• Force: 500-1000N
• Design Outputs
• Thrust
• Mass Flow Rate
• Combustion Temperature
• Combustion Pressure
ABS: Acrylonitrile Butadiene Styrene
3. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Amy Besio-Project Manager/Propulsion System Design 2
Testing Goals
4. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Josh Rou-Test System Design/Oxidizer Feed System 3
Fuel Grain
• Optimizing Exposure of Fuel Grain
Surface Area Using 3D Printing
• FDM
• ABS
• 51 mm x 180 mm
• Modeling
• CAD & CFD
• Fabrication
• 3D Printing
• Testing
• Baseline vs. HTPB
• Multiple ABS Geometries
FDM: Fused Deposition Modeling
ABS: Acrylonitrile Butadiene Styrene
HTPB: Hydroxyl-Terminated Polybutadiene
5. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Josh Rou-Test System Design/Oxidizer Feed System 4
Oxidizer Feed System
• Nitrous Oxide
• Self Pressurizing
• Subcritical at Room Temperature
• Effective Over Wide O/F Range
• Relatively Benign
• Components
• Holding Tank
• Routing Lines
• Solenoid Valve
• Check Valve
6. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Amy Besio-Project Manager/Propulsion System Design 5
Thrust Chamber
• Thermochemical Evaluation
• ABS/𝑁2 𝑂
• O/F: 8:1
• Combustion Temperature: 3500 K
• Combustion Chamber
• 54 mm x 200 mm
• Pressure: 3.445 MPa
• T6061-T6 Aluminum Alloy
• Manufacturing
• FEA
• Displacement: 0.5 𝜇𝑚
PDR
CDR
O/F: Oxidizer/Fuel Ratio
7. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Amy Besio-Project Manager/Propulsion System Design 6
Thrust Chamber
• Bulkheads
• Forward
• Injector
• Rear
• Nozzle
• Nozzle
• Graphite
• Optimal Expansion
• 2.3:1
𝐴 𝑒
𝐴 𝑡
= 2.3
Forward
Bulkhead
Aft Bulkhead
8. • Preliminary Design Requirements
• Factor of Safety = 5
• Compatibility
• Previous Designs
University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Richard Horta-Test System Design 7
Test Stand
PDR CDR
• Solution
• 1
1
4
" Square Steel Tubing
• Concrete Anchors
• Wheels & Bearings
• Superstrut Channels
• Clamps
9. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Richard Horta-Test System Design 8
Test Stand
• Fabrication Method
• Rail Frame Welding
• Drill Pressing
• Finite Element Analysis
• 0.241 mm Max. Displacement
10. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
John Seligson-Modeling & Results 9
Data Acquisition
• DAQ
• NI USB-6008 12bit
• Voltage Excitation
• Analog Input
11. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Jonathan Benson-Modeling & Results 10
Data Acquisition
• Combustion Chamber Pressure
• Pressure Transducer
• MLH01KPSB06A by Honeywell, Inc.
• Hardline Tube
• 3.175mm Stainless Steel Tube
• Thermal Insulator Coating
• LOCTITE Mil-PRF-907F
• Mass Flow Rate
• Average Mass Flow Rate
• Digital Scale
12. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
John Seligson-Modeling & Results 11
Data Acquisition
• Thrust
• Load Cell
• LCCD-500 “S”-beam by Omegadyne, Inc.
• Max Load: 2224.11N ±0.25%
• Temperature
• Nozzle exit to internal temperature:
• IR Meter
• UX-40P by Ircon
• Max Temp:1273±2 K
13. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Amy Besio-Project Manager/Propulsion System Design 12
System PDR CDR
Test Stand Structure $450.00 $100.00
Data Acquisition Equipment $500.00 $200.00
Rocket Components $650.00 $425.00
Propellant $200.00 $605.00
Total $1800.00 $1330.00
Budget
14. University of Central Florida-Senior Design Spring 2015
3D Printed Hybrid Rocket Fuel Grains
Amy Besio-Project Manager/Propulsion System Design 13
Current and Future Milestones
Apr May June July Aug Sept Oct Nov Dec
Design/Drafting
Manufacturing
Testing
Data Analysis
Contingency Period
Project Completion
Theoretical Propulsion
Calculations
Finalize Test
Stand Design
CDR Material
Purchase Build Test Stand
Manufacture Combustion
Chamber
HTPB Test
Initial ABS test
Grain Change
Tests
Compile Data Data Analysis
Retest
Final Analysis
(1:00-1:15 long)
(PDR - review)
As discussed in the PDR, the proposed solution is to optimize the exposed fuel grain surface area using 3D printing.
The printing method is FDM and the material composing the fuel grain will be ABS.
This combination provides advantages that aren’t available with traditional manufacturing methods, most important being flexibility in tailoring fuel grain geometries.
(CDR - “Detailed Design”)
Fuel grain dimensions were based on the O/F calculations. The fuel grain will be 180mm long and 51mm in diameter.
Modeling consists of cadding a regression model as seen here.
CFD of propellant flow within the combustion chamber will soon be modeled.
A consumer grade 3D printer will be used to fabricate the fuel grains and has a resolution of 100 to 400 microns.
Testing will first include a baseline of against HTPB and it will commence with multiple ABS geometry configurations.
(Note: How is this being optimized for the CDR?)
(around 1:30-1:40)
(PDR Review)
The oxidizer delivery system will provide the nitrous oxide content to the combustion chamber.
It was chosen for being a relatively inexpensive and stable for an oxidizer.
The biggest change from the PDR is that instead of using a 60lb. store tank, we’re now using a smaller 10lb. holding tank.
(CDR)
Nitrous oxide was also chosen for its ability to self-pressurize, meaning as it loses mass, it will re-pressurize back to a similar level.
This is due to being subcritical at room temperature.
Self-pressurization allows for N2O to be effective over a wide range in oxidizer to fuel ratio.
Components of the feed system were chosen based on being able to operate at pressures beyond 800psi.
The holding tank has a built-in pressure relief valve, pressure gauge, and a siphon tube.
Stainless steel braided routing lines of 1/4in. diameter and various fittings will connect the in-line components together.
Those inline components are the solenoid and check valves.
The solenoid valve will be remotely actuated via a microcontroller signaling and functions to release and cut off oxidizer flow.
Finally, the check valve will be used to prevent backflow into the holding tank.
(Note: Exact components and configuration are what makes the CDR different from the PDR.)
The front bulkhead will house the injector and ignighter and the rear bulkhead will house the nozzle.
The nozzle is one of the most important parts as it comverts the chemical energy into kinetic energy. We assumed that the nozzle would be optimally expanded to reduce the chance of shocks in the nozzle. The flow is subsonic at the inlet, =1 at the throat, and supersonic (2.8) at the exit. Using these mach numbers, we got an exit area to throat area equal to 2.3
Richard:
The thrust chamber will be mounted on to the test stand, a horizontal platform that is constrained to move axially on rails.
The design had to be safe, compatible with various measurement devices and thrust chamber sizes.
Preliminary designs evaluated utilizing linear bearings or a system that had up to 12 wheels. Both were deemed impractical due to cost and fabrication tims.
1-1/4 inch square steel tubing was selected to be the main structural element for the rails because of its rigidity, workability, and affordability.
The rail frame will be anchored to a pre-set concrete foundation with bolts and also be outfitted with measurement devices to obtain our data.
By rotating the rails 45 degrees, we are able to inhibit vertical and lateral motion while using 2 wheels at each corner.
Using Superstrut channels facilitates thrust chambers of varying lengths and diameters; simply by changing out the clamps and the distance between them.
The rail frame will be welded together as well as the rolling platform with the axle-bolts. Wheels and bearings will allow the platform to slide on the rails.
The axial superstrut members will be welded onto the platform and lateral members bolted.
Finite Element Analysis on the test stand shows that at a factor of safety of 5, the rail frame moves less than a quarter of a millimeter.