1. Joseph Zimmerman CU Aerospace LLC 9/5/2017
Capstone Senior Design Project Ideas
Joseph Zimmerman CU Aerospace LLC 9/5/2017

2. Summary Brief Company Overview
Thermoelectric Waste Heat Recovery (POETS)
Pulse Driver Circuit for Plasma Flow Control (related to NASA contract)

3. CU Aerospace Synopsis
CU Aerospace is a high tech aerospace company growing at ≈ 20% per year
Founded in 1998
Location: Champaign, Illinois
M2 Building (downtown Champaign)
Total number of employees (FTE): 12
Partners
6 Founding Partners
4 Jr. Partners
Core Technology Business Areas
Modeling and Simulation, Plasma-based Technologies, Spacecraft Systems (Propulsion & Software), Laser Systems, Advanced Aerospace Composites, and Aircraft Safety Systems
Products
BLAZE 7 Multiphysics software, THERMOSYS™ MATLAB/Simulink toolbox, Propulsion Unit for CubeSats (PUC), VascTech sacrificial fibers
Principal Customers
NASA, Air Force, DOE, Navy, MDA, JTO, NSF, Aerospace Primes

4. Company Divisions
R&D efforts in a number of advanced product areas with focus shift towards product hardware/software…
Aerospace
Materials
(Self-Healing, Sacrificial, & TPS)
Modeling & Simulation
(3D Multiphysics, Thermal Systems, Optimization Strategies)
Plasmadynamics &
Laser Systems
(Plasma Generation,
High Energy, & Diode Lasers)
Spacecraft Propulsion
(Electric & Solar Sail)
BLAZE-VI
PUC
VascTechTM
BLAZETM
THERMOSYSTM

5. Project Idea #1 “Thermoelectric Waste Heat Recovery in Mobile Systems”
POETS-sponsored joint MechSE-ECE team
POETS: Power Optimization of Electro-Thermal Systems
Potential applications in various CUA products
Proposed project objectives:
Apply thermoelectric effect to convert waste heat from battery-powered supply to stored potential
Demonstrate the ability of thermal energy harvesting to extend the operational life of the mobile power supply
Consider impact on size, weight, and practicality of the mobile system

6. Turbulent Separation Control Today
VGs on B
Passive flow control remains method of choice for commercial aircraft
VGs configured for takeoff, landing (~1-3% of flight time)
Cruise penalty
Most active actuation approaches suited for either low-speeds or high-complexity

7. Background Innovative Concept - Cyclotronic Plasma Actuator
Result: Low-Complexity, On-Demand Vortex Generator
Focused E Field
Thermal-based actuation of boundary-layer flow
Lorentz force coupling of arc filament and magnetic field to produce angular velocity
Sweeping arc-filament plasma for vortex formation and enhanced mixing
Turbulent boundary-layer separation control

8. Arc Breakdown Visualization
High-speed video of arc breakdown (Ansell, UIUC)
Acquired at 100,000 fps, playback 10 fps (1/10,000 real-time)
Arc breakdown every 0.5 seconds in playback
Correlates to 20 kHz driving frequency of AC circuit

9. Project Idea #2 “Tunable Pulse Circuit for Plasma Flow Control”
CUA-sponsored ECE-team (2-3 people)
Relates to joint CUA-UIUC NASA-funded program
Seeking improved compact, higher power circuit for atmospheric arcs in plasma flow control actuators
Proposed project objectives:
Design controller & transformer modules as compact circuit for UAVs (< 250 cm3 for both modules)
W input, VDC (battery) supply
Demonstrate tuning (5-50 kHz, varied duty cycle)
Analyze circuit efficiency
Test / demonstrate circuit with CUA benchtop testbed actuator

10. Questions?

11. Back-up Slides
for Discussion

12. Testbed Design and Benchtop Experiments
Goals: Improve actuation authority with increasing power, understand actuation properties with design
Multiple electrode and permanent magnet configurations
Power scaling of circuit AC driving frequency and amplitude
GBS Minipuls 2.2
Max 20 kVp-p driving voltage
Max 60 mA current output
5-20 kHz driving frequency
0-100% duty cycle control
Burst frequencies Hz
Alternative benchtop approaches:
Investigated so far: 60 Hz, RF
Future work: pulsed DC
GBS Minipuls 2.2

13. Testbed Configurations
Various coaxial formats applied
Excitation mechanisms:
5-20 kHz AC pulse, burst mode
60 Hz bipolar
13.56 MHz
13.56 MHz
excitation
Modified
commercial
spark-plugs
Large
cavity
Reconfigurable
coax
Etched PCB w/
embedded magnet

14. Embedded Magnet Concepts
Blown Arc
Coax
Top AC
Side
B-field
Bottom
Flow
E-field
Etch electrode patterns on copper-clad circuit board (chemical etch or CNC mill)
Attach / embed ring, disc, or bar magnet below board
Initial bench test with copper-clad FR4
Can be applied to alumina substrate (samples of curamik® obtained)
Potential for integrated cooling / simplified circuitry

15. 60 Hz Excitation vs. Voltage
Cyclotronic plasma actuator using 60 Hz bipolar excitation. Plasma pulses at 120 Hz (Tplasma = 8.33 ms). Exposure time is 1/15 s (66.7 ms, ~8 plasma pulses).
0.125” diameter inner electrode 110 copper rod w/ rounded at the tip, the is a 0.25” I.D. zinc-plated brass outer electrode, and the insulator is nonporous alumina ceramic.
Center electrode tip is positioned 0.125” below the outer electrode, recessed in the alumina tube such that the rounded tip is positioned approximately 1/32” above the alumina.
At low primary voltages (just above breakdown), the plasma takes on a filamentary appearance.
As voltage increases (and also the plasma current) the rotation rate increases and the appearance becomes more disc like.

16. V-I Results 13 kHz (GBS Minipuls) 60 Hz (12 kV transformer)
Readings from Minipuls Board, ACDelco
Tektronix P6015 HV Probe, IridiumIX
Pearson 411 Current Monitor, IridiumIX
Similar Vpk-pk across sparkplug at breakdown
Voltage drops as plasma impedance changes with increased current

17. Minipuls V-I Results ACDelco, 4 mm gap Iridium IX, 2.5 mm gap 5.2 kHz

18. Comparison of Arc Rotation with Actuator Configurations
Case 1
Case 2
Case 3
Case
Spark Plug
Magnet Dimensions
Centerline
B-Field (G)
Arc Rotation Rate (RPM) 1
NGK Iridium IX #3521
(2.5 mm gap)
1.5” OD x 0.75” ID x 0.75” Th.
675
6,173 2
3.0” OD x 0.75” ID x 0.5” Th.
2250
9,804 3
3.0” OD x 0.78” ID x 1.0” Th.
2500
10,638 4
ACDelco #41-902
(4 mm gap)
3,788 5
4,505 6
4,762
Video acquired at 5,000 fps with playback 60 fps (1/83 real time)
Arc forcing, rotation rate dependent on coax, magnet, and circuit configuration
Configuration can be tailored to change actuation effect or in-situ variation in arc rotation (for electromagnet)

19. Flat Plate Velocity Profiles
Similar profile
upstream of
actuation
Local velocity
defect from
actuation
Marginal
effect on
unactuated
flow
Flow recovery
and increased
BL momentum
Boundary-layer profiles:
Compare to effect of passive VGs (Velte et al., 2009)

20. Streamwise Flow Field Development
Actuation induces development of shear layer
Concentrated vorticity deflected away from wall
Subsequent increase in unsteadiness in velocity (σV)
Suggests enhanced mixing of flow field
Strategic placement of actuators is important!
Additional work planned to investigate control of separated BL
Subsequent study will characterize three-dimensional structure, use on airfoil model
Max unsteadiness
Max vorticity

21. VG and Plasma Recovery Comparison
VG Strip
Single VG
Single VG
Single Cyclotron
(Underpowered)
Single Cyclotron
(Underpowered) No
Control
DBD
Effects of plasma actuator qualitatively similar to conventional VG
Plasma actuator underpowered resulting in lower difference in ΔCp
VG may be oversized for application (h > δ)
Phase I electronics limited power input  significantly increase power/current to plasma in Phase II to obtain similar VG ΔCp performance while retaining on-demand actuation