my: The overall goal of our project increase the regression rate of hybrid rocket fuel grains by increasing the available surface area. As specified by the customer, the test will be five seconds, have an internal combustion pressure of 500psi and a achieve 500-1000N of thrust. We will be measuring force, propellant mass flow rate, combustion temperature and pressure.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsAmy Besio-Project Manager/Propulsion System Design 2
Testing Goals
Amy Kate Besio
To observe the interaction of nitrous oxide and abs, we designed a testing apparatus capable of withstanding the desired forces. The oxidizer is fed through a series of tubing and check valves where it is then injected into the thrust chamber and ignited to initiate combustion. The test stand will house the thrust chamber inside a blast shield to contain any particles expelled if theres an explosion.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsJosh Rou-Test System Design/Oxidizer Feed System 3
Fuel Grain• Optimizing Exposure of Fuel Grain Surface Area Using 3D Printing
(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 and using CFD on the propellant flow within the fuel grains.The 3D printer being used to fabricate the fuel grains is a DaVinci 1.0 with a resolution of 100 to 400 microns.Testing will include a baseline of against HTPB and then multiple ABS geometry configurations.(Note: How is this being optimized for the CDR?)
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsJosh 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
(around 1:30-1:40)The oxidizer delivery system will provide the nitrous oxide content to the combustion chamber. Nitrous oxide was chosen for its ability to self-pressurize, meaning as it loses mass, pressure will be relatively maintained.This is due to being subcritical at room temperature.Self-pressurization allows for nitrous oxide to be effective over a wide oxidizer to fuel ratio range. Nitrous oxide is also one of the more stable oxidizers.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.Inline components are the solenoid and check valves.A solenoid valve will be remotely actuated and functions to release and cut off oxidizer flow.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.)
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsAmy Besio-Project Manager/Propulsion System Design 5
Thrust Chamber
• Thermochemical Evaluation• ABS/• 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
PDR
CDR
O/F: Oxidizer/Fuel Ratio
Amy Kate Besio
Before we did any calculations, we performed the combustion analysis of abs and nitrous oxide. This information was used to compute the oxidizer to fuel ratio of 8:1. Assuming complete combustion, we found the combustion temperature to be 3500 K.We simplified the design from the PDR so it would be easier to machine, reload fuel grains, and interchange parts. The combustion chamber is sealed by two bulkheads with bolts and an oring. We chose T6061 aluminum because its easy to machine and can withstand the expected performance. The chamber will be extruded from a 4” aluminum round stock piece either in the oncampus machine shop or by ourselves depending on timing.The FEA which showeddisplacement areas and a total displacement of .0005mm.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsAmy Besio-Project Manager/Propulsion System Design 6
Thrust Chamber
• Bulkheads• Forward
• Injector• Rear
• Nozzle• Nozzle
• Graphite• Optimal Expansion
• 2.3:1𝐴𝑒
𝐴𝑡
=2.3
Forward Bulkhead
Aft Bulkhead
Amy Kate Besio
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.
• Preliminary Design Requirements• Factor of Safety = 5• Compatibility
• Previous Designs
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsRichard Horta-Test System Design 7
Richard: The thrust chamber will be mounted on a horizontal platform that is constrained to move axially on rails. Preliminary designs evaluated utilizing linear bearings or system that had up to 12 wheels. Both were deemed impractical due to cost and fabrication time respectively.By rotating the rails 45 degrees, we are able to inhibit vertical and lateral motion while using 2 wheels at each corner. The stand will be compatible with thrust chambers of varying lengths and diameters; simply by changing the clamps and distance between them.The stand will be fabricated by welding steel square tube for the frame, adding The stand will also be outfitted with measurement devices to obtain our data.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsRichard Horta-Test System Design 8
• Finite Element Analysis• 0.241 mm Max. Displacement
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsJohn Seligson-Modeling & Results 9
Data Acquisition
• DAQ• NI USB-6008 12bit• Voltage Excitation• Analog Input
Amy Kate Besio
John: To characterize the performance of the fuel grains we will test, a system of measurement devices will be used to measure Combustion chamber pressure by pressure transducer, Propellant mass flow rate by digital scale, Thrust by load cell, and combustion chamber temperature by IR thermography. These devices will be connected to a DAQ for data acquisition. A NI USB-6008 will be purchased to provide voltage excitation to the devices and analog input from the devices. The DAQ will feed the data into a computer running LabView to process the data.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsJonathan Benson-Modeling & Results 10
Benson: Combustion Chamber Pressure:Shown in Photo: Chamber pressure will be taken using a pressure transducer and a coated hardline tube. The Hardline tubing will be coated with LOCTITE, as you can see in this photo (Figure 2). The pressure from the combustionchamber will enter the hardline tubing and reach the pressure transducer. The pressure transducer will read the indicated pressure and outputted signals will be transmitted to the DAQ, as you can see here (point to Figure 1 diagram).Pressure Transducer:The pressure transducer is a Sealed Gauge 3.175mm Pressure Transducer that will be purchased from Digi-Key Electronics. This pressure transducer is optimal because its pressure range is 0 - 6.894 MPA (1000psi) and a operatingtemperature of 233 Kelvin to 398 Kelvin. The pressure within the combustion chamber is estimated to be 3.447 MPa,in case of any pressure spikes, a pressure transducer that reads double the expected pressure range is going to beused. The operating temperature is only up to 398 Kelvin. This will be accounted for by using a Hardline TransitionHardline TubeThe hardline tube will be made out of 3.175mm Stainless Steel and will be 7 inches long. The reason for this hardline is it will dissipate the heat of the gas as it travels to the pressure transducer. Using 1 dimensional nodal heat transferanalysis. A hard line length was based on the boundary layer thickness, material, and initial and final temperatures. The heat inside the combustion chamber is expected to be 2700 Kelvin which is too hot for the melting point ofStainless Steel which is 1600 Kelvin. LOCTITE will be used as a thermal insulator to coat the tube and prevent the tube from melting. The silver grade anti-seize is rated to 1200 Kelvin. (Should I include safety of how to handle the LOCTITE??)Mass Flow Rate:Mass Flow Rate is the mass of a substance that passes per unit of time. The average oxidizer mass flow rate and the fuel mass flow rate will be acquired using a weighing scale. The oxidizer and motor will be weighed separately before the test. After the test is over, they will be weighed separately again. Using digital imaging, the amount of oxidizer used during combustion can be accurately recorded. Using the following equation, the mass flow rate can be calculated.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsJohn 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:12732 K
Amy Kate Besio
John: ThrustThe overall thrust measurement will be read by a s-beam load cell by Omegadyne, Inc. The load cell has a maximum load of 500 pounds with a 0.25% accuracy. With a maximum overload of 300%, the load cell is capable of withstanding the maximum forces the test stand is designed for. In a study by Utah state, the same load cell was used in a similar application. The measurements rose from 0 to 800N within 1 second, proving the viability of the load cell’s response time. A ½”-20 male thread bolt will be used to secure the load cell to the forward superstrut cross member on the test stand. The DAQ will provide voltage excitation and receive voltage output from the load cell.TemperatureThe temperature of the nozzle exit will be measured by IR thermography and related to the internal temperature of the combustion chamber by this equation, incorporating the specific heat of the fuel mixture and the exit Mach number. A UX-40P IR meter will be loaned for the duration of the project. The maximum temperature reading is 1000C with an accuracy of +/- 2C. The IR meter includes its own power source, so voltage excitation from the DAQ is unnecessary. The Voltage output will go to the DAQ for data aquisition.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsAmy 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
Amy Besio
We reduced the budget significantly from the initial projected budget. Although some areas were reduced, heavier emphasis was placed on other systems like the Oxidizer system. At this time, we'd like to thank TSG, Boeing, Apogee Engineers, and FSGC for fulling funding this project.
University of Central Florida-Senior Design Spring 20153D Printed Hybrid Rocket Fuel GrainsAmy Besio-Project Manager/Propulsion System Design 13
Current and Future Milestones
Apr May June July Aug Sept Oct Nov Dec
Design/Drafting
ManufacturingTesting
Data Analysis
Contingency Period
Project Completion
Theoretical Propulsion Calculations
Finalize Test Stand Design
CDR Material Purchase Build Test Stand
Manufacture Combustion Chamber
HTPB TestInitial ABS test
Grain Change Tests Compile Data Data Analysis
Retest
Final Analysis
Amy Besio
We plan to order materials in beginning of may and compile begin manufactuing by june first. In mid june, we'll do to initial htpb/abs comparison test and continue the grain change tests in july. During august and september we'll compile and analyze the data, and retest in october if necessary.
Amy Besio
We plan to order materials in beginning of may and compile begin manufactuing by june first. In mid june, we'll do to initial htpb/abs comparison test and continue the grain change tests in july. During august and september we'll compile and analyze the data, and retest in october if necessary.
