Vanderbilt University Aerospace Club

1. Vanderbilt University Aerospace Club USLI Preliminary Design Review December 9, 2010

2. Agenda for Presentation • Changes Since Proposal • Vehicle Criteria • Payload Criteria • Educational Outreach • Conclusion • Questions

3. Changes Made Since Proposal • Vehicle: • Detailed design established • Dimensions slightly altered • Payload: • Cool half of TEGs instead of all • Invert cryogen tank • Educational Engagement: • Expanded and improved • Test plans established for vehicle and payload

4. Vehicle Criteria

5. Vehicle Dimensions • Length: 10’-5” • Diameter: 7.5” • Weight: about 64 lbs loaded • Assumes additional “ballast” weight added • Can be adjusted for wind, or to shift the CG forward/aftward • Center of presure at 95.8” aft

6. Materials • Body • two 4’-long epoxy-reinforced phenolic DynaWind body tubes from Giant Leap • Nosecone • ogive-shaped, commercially available, fiberglass nosecone with 29” of exposed length – from Public Missiles • Centering Rings and Bulkheads • ½” birch plywood (4 centering rings for the MMT) • Fins • swept-trapezoid, Nomex honeycomb fin stock from Giant Leap

7. Static Stability Margin • Rocket Diameter • 7.5” nominal ID • Center of Pressure • 95.8” aft (with M520 motor) • Center of Gravity • 82.5” aft • Stability Ratio: 1.73 calibers

8. Safety Verification and Testing • Subscale launch • Re-evaluate the thrust and flight characteristics using an aft payload attachment • Full scale launch • First test launch to test its flightworthiness • Second launch to test the payload and its effects on the rocket flight • Ground testing • Test the ejection systems on the ground prior to full scale test launch

9. Safety Verification and Testing • RockSim design and simulation • Subscale launch • Subscale rocket will be flown to testsystems: • Recovery/charge deployment • Motor set up • Launch Operations • Full scale launch • First test launch to test flightworthiness • Second launch to test payload and its effects on the rocket in competition configuration • Ground testing • Test the ejection systems on the ground prior to full scale test launch

10. Motor Criteria: • Provide sufficient thrust for stable, safe flight from a 16’ launch rail. • Maximize rocket burn time to allow for experimental data collection. • Achieve an altitude of one mile AGL. • Considered: • Cesaroni Pro98 L610 • Cesaroni Pro98 M520  Selected

11. Motor • Selected Motor: Cesaroni Pro98 M520 • Longer burn time provides more data • Higher initial thrust = better initial thrust-to-weight ratio

12. Cesaroni Pro98 M520 • Initial thrust: 1184 N / 266 lbf • Thrust to weight ratio: 4.2 : 1 • Rail exit speed: 52 ft/s • Final altitude: 5,287 ft AGL • Depends on wind conditions • Can be adjusted by changing the rocket’s weight

13. Motor Safety Verification and Testing • Static fire tests • Static fire tests on the ground to determine the effectiveness and safety of the payload • Build upon last year’s static fire data regarding, e.g., the Krushnic effect • Ideally, static fire an M520 motor – this depends on availability of large static fire facilities • Test launches • Ensure that the rockets (full scale and subscale) have been constructed safely and that the selected motors are sufficient Motor static fire stand

14. Vehicle Recovery • Dual deployment controlled by redundant MAWD altimeters • Separation occurs: • at the nosecone joint • at the joint between the body tubes • Rocket descends as one unit • Parachutes • Main parachute • 144” dia. = 18 ft/s descent • Housed in nosecone • Drogue parachute • 60” dia. = 65 ft/s descent • Housed in the forward body tube, aft of the avionics bay

15. Vehicle Recovery • Electronics • Two-way redundancy • Identical MAWD systems • Completely isolated from each other • Each fires its own set of ejection charges and has its own batteries (2 x 9V each) • Housed in avionics bay, separate from all payload electronics • Avionics bay drilled with pressure sampling holes according to MAWD documentation

16. Vehicle Recovery • Black powder charges • Sized according to equations referenced in PDR • 0.24g 4F black powder per 1” of pressurized chamber • Designed to effect 450 lbs of separation force • #6-32 nylon shear pins: 3 x 114 lbs = 342 lbs (max) needed for separation

17. Vehicle Recovery • Ground testing • Entire deployment system will be ground tested • Remote-controlled firing of deployment charges • Ensure adequate charge sizing, shear pin selection • Performed under supervision from Safety Officer, with approval from Mechanical Engineering safety coordinator

18. Scientific Payload Criteria

19. Payload Summary • Use cryogenic injection to simulate airplane cruise conditions • Evaluate performance of TEGs Jet engines convert heat to work, but about 50% of energy is wasted.

20. Validation of Payload • 2D experiments conducted: • Measure power and temperature of single TEG • Vary wind speed • Inject cryogen for further cooling

21. TEG Assembly LN2 Injector Vasa Fan Heat Gun/Blowtorch Wind speeds up to 100 mph. Heat gun provides steady-state 120 C Blowtorch: 220 C 3.3 Ω 3.3 Ω 3.3 Ω

22. Results Heat Gun Results Blow Torch Results

23. Results High Temperature Thermal Interface Material Results

24. Conclusions • Waste heat recapture improves with wind speed [flight speed]. • Waste heat recapture improves with cooling [lower ambient temperature]. • Overall waste heat recovery was 2.7%, opposed to theoretical limit of 8.6% • Caused by thermal interface deterioration on the hot side. • Solution is to explore the use of more robust TIM. • Results point to favorable usage in aerospace applications.

25. Theory • Matching Nusselt number can verify feasibility of simulating airplane flight through rocketry

26. Payload Design • 2 Payload Sections • Forward payload: Data Acquisition Electronics Cryogenic container, Valves and delivery lines • Aft payload: Thermoelectric engine with cryogen injectors

27. Cryogen Storage Tank • Modified cryosurgery Dewar • Hand valve replaced with solenoid valve • Tank inverted and lines routed for filling and pressure relief

28. Solenoid Valve • Compact solenoid valve rated for Liquid Nitrogen Use • Actuated by 24 volt direct current • ¼” NPT fittings

29. Safety Verification and Testing • Ground based testing of individual components • Subscale launch on “Thermo-ElMo” • Full scale launch

30. Valve Control Electronics • Rocket Data Acquisition System (RDAS) igniter output activated by ‘g-switch’ • Pulse sent to 74121 ‘single shot’ IC • Relay sends 24 V DC to cryogen valve

31. Aft Payload and Injection • Aft payload machined in-house from aluminum • Welded to motor retaining cap for rocket attachment • Injector constructed from slotted stainless steel, similar to 2-d experiments • 3 cooled TEGs and 3 control

32. Data Acquisition • RDAS system activated by ‘g-switch’ • One data stream each for the cooled and control TEG sets • Hot and cold side temperature measurements • Power measurement across an impedance matched resistor network

33. Payload Safety • Cryogen system design for filling on launch pad eliminating risk of exposure during assembly • G-switch failsafe to prevent accidental cryogen release • Aft payload proven secure through multiple full scale flight tests

34. Payload Development • Cryogen system assembly and flow testing • 3-D ground based testing using rocket test stand • Full scale cryogen system test using the 2009-2010 rocket

35. Outreach Lesson PlanEnergy, Engines & Propulsion Thermal Energy Combustion & Propulsion Thermoelectric Energy Conversion

36. Expose students in 5th to 8th grades to concepts of combustion, energy conversion and rocket propulsion • Build upon students’ prior scientific knowledge to identify new specific areas of interest • Provide opportunity for students to learn about mechanical and aeronautical engineering concepts, potentially leading to study in or careers in these fields Educational Engagement Mission

37. Educational Engagement Timeline (All visits occur in Nashville, TN)

38. Adiabatic Compression • This lesson will be presented to students in the 5th-8th grade range. • The demonstration will help the students understand the definition of an ‘adiabatic process’ and give a basic understanding of the Diesel engine combustion cycle. • The ground glass tube of the compressor is surrounded by plastic in the unlikely event that the glass tube breaks. • The power of adiabatic compression • Ignites paper for a dramatic demonstration

39. Thermoelectric energy conversion

40. Thermoelectric Energy Conversion • In order to demonstrate the scientific content of the project and to engage students' interest in thermoelectrics, a device has been prepared that exploits a temperature difference across a thermoelectric generator (TEG) to power a light bulb. • Temperature difference is created by blowing a common hair dryer on one side of the TEG, and ice on the other side. • As the heat settings on the hair dryer are changed, the brightness of the light bulb will change, demonstrating the correlation between temperature difference and power generation • A discussion will follow the experiment asking for student input on where TEG’s could one day be useful in their everyday lives

41. Rocket Propulsion • An Estes D12-5 model rocket motor will be fixed in a test stand and its thrust will be measured by a Pasco PasPort Force Sensor. • The thrust and impulse terms will be explained to the students and the forces on a model rocket will be analyzed. • The Estes D12-5 motor will be secured inside the test stand using four set screws. thrust

42. Summary • Rocket: • 10’-5” tall, 7.5” diameter, 64 lbs, dual deployment • Cesaroni Pro98 M520 provides 4.2 : 1 thrust-to-weight • Payload: • Cryogenic injection system • Aft-mounted thermoelectric engine • Outreach: • Developed curriculum and have begun planning educational engagement events

43. Questions