EHD Pump. Critical Design Review University of Nebraska Lincoln NASA Goddard Space Flight Center December 7, 2012

Transcription

1 EHD Pump Critical Design Review University of Nebraska Lincoln NASA Goddard Space Flight Center December 7, 2012

2 Mission Overview

3 Mission Overview Mission Overview Organizational Chart Theory and Concepts Concept of Operations Expected Results

4 Mission Overview Goal statement: The total mission goal is to implement known and experimental EHD technology in thin-film evaporation techniques for the purposes of two-phase flow in microgravity. To verify success of the experiment, we will require data on fluid flow and temperature from multiple sources. We expect high values of thermal transfer coefficients derived from total heat fluxes on the payload target. Results will be used in designs of a similar long-term experiment that will be held on the ISS. Future applications include EHD pumps for onboard circuits and microprocessor integration.

5 Mission Overview Multidiscipline Engineering Collaboration GSFC: Experiment Design and Fabrication University of Nebraska Lincoln Aerospace Club: Experiment Operations/Structure/Subsystems: Data Acquisition Power Distribution Flight Operations Structure Program Objectives EHD Thin Film Evaporation micro-gravity data in support of ISS Microgravity Experiment Science Review

6 Micro-Scale EHD Science Goals: ISS Experiment Preliminary Effects of gravity of interaction of flow fields and electrical fields with and without phase change Effects of gravity of electrical charge generation in meso- and micro-scale Effects of gravity on electrically driven film boiling Applications: EHD pumps for on-board processors EHD pumps for micro- and nano-scales High heat flux thermal control Multi-functional Plates

7 Micro-Scale EHD The effects of gravity on the interaction of electric fields and flow fields in the presence of phase change in small and large scales. The effects of gravity on the net electrically generated two-phase flow rate in small and large scales. The effects of gravity on electrically driven film boiling (includes extreme heat fluxes). Convective boiling heat transfer coefficient in low mass flux levels in the absence of gravity.

8 Theories of Operation EHD Force Components Electrophoretic: charge generation by electro-chemical reaction Liquid Pumping Function of electric field, temperature & fluid quality Di-electrophoretic: take advantage of permittivity gradients (e.g, two phase flow) Phase & Fluid Management Thin Film Evaporation Electro-striction: Compressible Flow

9 EHD Electrophoretic Force Generation Asymmetric Geometry leads to higher pressure head: configuration is impractical for spacecraft applications

10 EHD Electrophoretic Force Coulomb (electrophoretic) force generated by: Apply discrete electric field to dielectric fluid using asymmetric electrode geometry Electrolytes in fluid subject to dissociation-recombination reaction that favors dissociation in presence of electric field Attraction of hetero-charges to electrode generates flow FLOW L 1 L 3 L 2 L 4 Electrodes in wall; less asymmetry - lower pressure head generated

11 Altitude Concept of Operations t 1.6 min Altitude: 91 km Power on EHD Pump Apogee t 2.8 min Altitude: 115 km t 5 min End Experiment End of Orion Burn t 0.6 min Altitude: 52 km Power to resistors t 5.5 min Chute Deploys t = 0 min -G switch triggered -All systems on -Begin data collection t 15 min Splash Down

12 Concept of Operations Event Action Launch G switch triggered Arduino powers on End of Orion Burn Send power to platinum resistors Data logger and sensors active, collecting data Time 1.6 min Power to EHD Pump experiment End Experiment EHD Pump and resistors powered off Data logging stopped and sensors inactive Arduino in idle state

13 High-Range Accelerometer Data

14 High-Range Radial and Tangential Acceleration

15 Expected Results For each of the RTDs in the experiment, the voltage will be stored and used to calculate the heat transfer coefficient of the experiment. We are measuring the two phase heat transfer coefficients for thin film liquid boiling using EHD conduction technique. We expect to see heat transfer coefficients above 150 W/cm 2 K

16 Design Description

17 Changes Since PDR Battery Container PDR: Batteries lay on their sides, arrayed around the center CDR: Batteries stand up, arrayed circularly

18 Changes Since PDR Dampening PDR: Piston-Cylinder with internal secondary dampening CDR: Piston-Cylinder with external vibration dampening, alternative material

19 Changes Since PDR Double Containment for Fluids To counter the possibility of the dielectric fluid leaking, the hose connecting the experiment and fluid reservoir will have a secondary containment implemented.

20 Changes Since PDR Si Wafer Support PDR: 0.5 inch Sorbothane pad for vibrational dampening CDR: Rapid prototyped plate with access for RTDs

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22 De-Scopes and Off-Ramps Scope has not changed since PDR No off-ramps No high risk components thorough testing with GSFC to verify

23 Mechanical Design Overview

24 Physical Models Battery Array Electronics and Fluids System Experiment System

25 Battery Array 24 NiMH batteries Two 9-volt batteries Custom-made battery housing Rapid prototyped Connects NiMH batteries in series

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27 Electronics and Fluids Systems Experiment Sensors Power Supply G-Switch Power Supply Arduino, Sensors, OpenLog Z-axis accelerometer Fluid Reservoir

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29 Experiment System Two stages of dampening Piston-Cylinder System Internal Vibration System Experiment housing

30 Stage 1 Dampening Experiment system is constrained on both sides by the Piston-Cylinder system The pistons remains static, allowing the experiment system to move axially Dampening materials absorb most of the impulses in all directions

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32 Stage 2 Dampening Primary purpose is to absorb vibrations Absorbs most of the vibrations Constrains the experiment housing in all directions with dampening material Side tabs keep experiment aligned axially

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34 Experiment Housing Contains the EHD pump and sensors Two electronic ports 25-pin connector for thermal resistors located underneath the EHD Power connector for EHD Two fluid ports for inflow and outflow Vacuum-sealed

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36 Electrical Design Elements Control subsystem Power Controls Canister sensors Experiment subsystem Power Heater EHD pump Sensors

37 Changes Since PDR Finalized canister sensor models Changed activation method to 1SYS.1 Addition of external ADC Replace multiplexor with protoshield

38 Controls Power: rechargeable batteries Tenergy 9V NiMH 250mAh x2, in parallel Three PCB assemblies Arduino, sensors, data Z-axis accelerometer G-Switch

39 Controls Block Diagram

40 Arduino Assembly Arduino Mega 2560 R3 Manages power distribution to experiment Interface to all sensors Logs data to storage Powered on before flight: 1SYS.1 Protoshield Breadboard stacked on top of Arduino Canister sensors, OpenLog are soldered on

41 Protoshield OpenLog Connected to Arduino Serial 57.6 Kbps Flash storage: 1GB microsd Logs any data received from serial G-switch Signals launch Determines when timed events begin

42 Protoshield XY-axis accelerometers Analog Devices Inc. High-range model: AD22284-A-R2 ± 37g Low-range model: ADXL203CE ± 1.7g Both sensors on one PCB Six lines High/low X analog outputs High/low Y analog outputs VCC (+5V), GND

43 Protoshield Pressure sensor Honeywell Sensing and Control ASDX015A24R 0 to 15 psi range Three lines Analog output VCC (+5V), GND

44 Protoshield Temperature sensor National Semiconductor LM50CIM3/NOPB Range of -40 to 120 C Three lines Analog output VCC (+5V), GND

45 Z-Accelerometer Assembly Analog Devices Inc. High-range model: AD22279-A-R2 ± 35g Low-range model: ADXL103CE ± 1.7g Both sensors on one PCB Four lines High/low Z analog outputs VCC (+5V), GND

46 Experiment Subsystem Power Heater EHD Pump Sensors External ADC

47 Experiment Block Diagram

48 Experiment Subsystem Power Batteries Tenergy 1V NiMh 10C High Drain Rechargeable 2/3A 1600mAh x24, in series Experiment power supply Pico Electronics Series VV, part 48VV3 Input: 15 to 48V Output: 450 to 3000V, max 2.667mA Wheatstone power supply: TBD Must provide highly stable, constant voltage

49 Experiment Subsystem Resistive heater Platinum resistors Heat silicon wafer EHD Pump Provided by GSFC 2000V at < 1mA Sensors Provided by GSFC models TBA Pressure sensor Flow meter

50 Experiment Subsystem Sensors Temperature x20 RTD sensors Very accurate nominal resistance Individual Wheatstone bridge circuit per sensor

51 Experiment Subsystem External ADC Recent development: Arduino ADC is undesirable Questionable noise levels Simple on-chip ADC Additionally from multiplexor? Long signal wire travel Low resolution: 8-bit 1024 values 1V reference: ~ 1mV steps

52 Experiment Subsystem External ADC Proposed model: Texas Instruments ADS1258-EP 48-pin IC 24-bit resolution 1.68 million values 5V reference: 298 nv steps 16-channel Eliminates the need for external multiplexor 23.7 ksps per channel All channels sampled in 700 μs theoretical 1.4kHz sample rate Low-noise emphasis Digital communication with Arduino via SPI

53 Experiment Subsystem External ADC Implementation Noise minimization Converting on-pcb with Wheatstone bridges Physically relocate near experiment» Only digital signals to Arduino travel significant distances May use multiple chips depending on sensor quantity Compact size: 7.2 mm square Still less space compared to mux

54 Software Design Elements Written in C for Arduino Augmented using open-source libraries TimeAlarm: event scheduling Serial communication Major tasks Time-based power distribution Output power-on and -off signals at certain flight times Controls experiment, heater

55 Software Design Elements Major tasks Read sensor data From experiment, canister Log data to storage Output to OpenLog over Serial

56 Software Flowchart

57 Time-Based Events Using TimeAlarm library Pseudo-realtime event scheduling One-second precision Events at certain times Power on resistive heater Power on experiment Power off experiment and resistive heater

58 Prototyping/Analysis

59 Battery Case FEA Solidworks Finite Element Analysis on Battery Case Material: ABS (acrylonitrile butadiene styrene) Property Value Units Young s Modulus 2000 MPa Poisson s Ratio N/A Shear Modulus MPa Tensile Strength 30 MPa Density 1020 kg/m 3

60 Fluid/Electronics Base FEA Solidworks Finite Element Analysis on load carrying support Material: High Viscosity Polycarbonate Plastic Property Value Units Young s Modulus 2320 MPa Poisson s Ratio N/A Shear Modulus MPa Tensile Strength 62.7 MPa Density 1190 kg/m 3

61 Piston FEA Solidworks FEA on primary load carrying element in dampening system Material: Aluminum 6061 Alloy Property Value Units Young s Modulus 69 GPa Poisson s Ratio 0.33 N/A Shear Modulus 26 GPa Tensile Strength MPa Density 2700 kg/m 3

62 Manufacturing Plan

63 Mechanical Elements Battery Canister 3D printed here at the University of Nebraska Experiment GSFC has designed, and plans to manufacture the actual experiment Dampening System and Canister Discussions are in progress for GSFC to manufacture the experiment canister, as well as the dampening system

64 Mechanical Elements Experiment Fluid Reservoir Materials GSFC plans to manufacture this 3D printed parts will be printed out of industry standard ABS plastic All custom manufactured metal components will be made of industry standard 6061 aluminum

65 Mechanical Elements Materials Tubing Material has yet to be decided on Sorbothane will be used as a dampening material in our system Construction All parts put together in final assembly in-house at the University of Nebraska

66 Mechanical Manufacturing Plan Date Event 1/23/2013 Purchase materials and components 1/23/2013 3D print necessary parts 1/27/2013 Begin component machining 1/30/2013 Begin experiment section construction 2/10/2013 Begin experiment subsystem testing

67 Electrical Elements Yet to be manufactured Sensor PCB Solder sensor boards to single PCB Fairly simple: one revision expected Wheatstone bridge, ADC circuit May require 2 or 3 revisions Yet to be procured Batteries for controls and experiment Experiment, Wheatstone power supply

68 Electrical Manufacturing Plan Date Event 1/25/2013 Purchase remaining components 1/30/2013 Print finalized circuit boards 2/5/2013 Begin Tier 2 construction 2/10/2013 Begin experiment subsystem testing

69 Software Elements Simple proof-of-concept completed Log 20 thermistors to storage To be completed: Logging of additional sensors Time-based events No inter-block dependencies

70 Software Manufacturing Plan Date Event 12/21/2012 Complete first code iteration 1/4/2013 Test functionality with all sensors 2/8/2013 Verify reliable event timing 2/10/2013 Begin experiment subsystem testing 2/17/2013 Finalize code

71 Testing Plan

72 Mechanical Testing Whole assembly will be manufactured and assembled, including the canister Will be tested at GSFC when put together Impact testing to simulate rocket launch forces and axial force on EHD experiment Vibration simulation testing will test energy transfer to EHD experiment

73 Sorbothane Test Procedure Ran In House tests on Sorbothane s ability to absorb force Track angled at 0.5 degrees from table surface Frictionless cart (mass: kg) released 33.5 cm up ramp Force sensor at bottom of ramp Control experiment done without sorbothane, then a sorbothane pad was placed as a buffer in front of the force sensor

74 Sorbothane Test Results Without Sorbothane Run # Time (s) Max force (N) Mean Force (N) Impulse (N*s) With Sorbothane Run # Time (s) Max force (N) Mean Force (N) Impulse (N*s) Test ran with 1 kg mass added to cart with Sorbothane buffer in place Force: N

75 Without Sorbothane

76 With Sorbothane

77 Electrical Testing Ensure no current without WFF Verify experiment PSU signaling Interaction with software Verify sufficient battery life for experiment and controls Much higher than time of flight and pre-, postflight buffer Verify sensor operation and data validity Testing planned for winter break

78 Software Testing Ensure time-based events fire at correct time Especially Arduino-to-experiment PSU signaling Test G-switch polling Verify that minimum sampling rate is maintained Prototype software: ~600 Hz Testing planned for winter break

79 Risks

80 Consequence Power Risk Matrix Risk 1, 2 Possibility EHD pump does not operate if Risk 1: EHD power supply fails Risk 2: EHD battery is discharged before launch

81 Consequence Controls Risk Matrix Risk 1, 3 Risk 5 Risk 4 Risk 2 Possibility Risk 1: Experiment failure if Arduino does not signal EHD PSU at appropriate time Risk 2: Loss of data precision if the Arduino cannot sample sensors rapidly enough Risk 3: Unable to log all data if multiplexor introduces compatibility issues with sensors Risk 4: Inaccurate data if vibrations cause loose connections Risk 5: Erroneous data if programming faults exist

82 Consequence Experiment Risk Matrix Risk 1 Risk 4 Risk 2 Risk 3 Possibility Risk 1: Entire experiment fails because silicon wafer fractures Risk 2: Working fluid leakage Risk 3: Loss of working fluid due to container integrity failure, reservoir integrity failure, or seal failure. Risk 4: Experiment loses power due to electrical connection malfunctions.

83 Consequence Structure Risk Matrix Risk 1 Risk 2, 3 Possibility Risk 1: Experiment fails if structure platforms fail to support components Risk 2: Excessive vibration along with dampening failure causes experiment to lose structural integrity. Risk 3: Dampening material acts unpredictably, causing greater impulses to translate through.

84 User Guide Compliance

85 User Guide Compliance Mass Payload mass: lbs Total mass: 17 lbs Center of Gravity X = in Y = in Z = 4.93 in

86 User Guide Compliance Rechargeable NiHM batteries Tenergy 2/3 A, 1600 mah (x24) Tenergy 9V, 250 mah (x2)

87 User Guide Compliance 1.SYS.1 activations system by WFF Arduino powered on by WFF at T-2 min WFF will have full control over control power Once controls are powered off, so will the entire experiment

88 Project Management Plan

89 Schedule Date Event 1/18/2013 Final Down Select - Flights Awarded Legend 1/18/2013 Stage 2 Funding Proposal submitted to NASA NE Project Milestones 1/23/2013 Order Components and Construction Materials COSGC Expectations 1/25/2013 Begin Payload Subsystem Construction 1/25/2013 Online Progress Report 3 Due 2/15/2013 Individual Subsystems Testing Reports Due 2/25/2013 Start Subsystems Integration 3/12/2013 Online Progress Report 4 Due 3/29/2013 Payload Subsystem Integration and Testing Report Due 4/2/2013 Begin Full Payload Sctructural Test (Vibration, Vacuum, etc) 4/15/2013 RockSat Payload Canister sent to customers 4/26/2013 First Full Mission Simulation Test Report Due 6/3/2013 Launch Readiness Review Presentations 6/12/2013 Travel to Wallops Flight Facility, 1st Group 6/18/2013 Travel to Wallops Flight Facility, 2nd Group 6/14-18/2013 Integration/Vibration at Wallops 6/20/2013 Launch Day

90 Monetary Budget Section Part Material Material Subtotal (USD) Manufacturing Subtotal (USD) Experiment 2x Dampening base plate Aluminum x Inner dampening plate Aluminum Experiment housing shell Aluminum x Experiment housing plate Aluminum Computer/resivior mounting plate Makrolon x Stage 1 Dampening pads Sorbothane x stage 2 dampening pads Sorbothane Miscellaneoud Dampening pads Sorbothane x Pipe elbows Aluminium Hardware 16x Nuts Steel x Threaded rod Steel x SHCS Steel x Copper O-Ring Copper Printed Parts 2x Piston Wall ABS Plastic Lower Battery Plate ABS Plastic Upper Battery Plate ABS Plastic Subtotal Total Cost

91 Monetary Budget Section Part Quantity Unit Price (USD) Subtotal (USD) Electrical/Controls Arduino Mega2560 Rev Mux Shield Payload Pressure Sensor Payload Temperature Sensor Payload Low Range Z-Axis Accelerometer Payload High Range Z-Axis Accelerometer Payload Low Range X&Y-Axis Accelerometer Payload High Range X&Y-Axis Accelerometer Nickel Tabs Flow meter (donated) Subtotal Tier 2 Reservoir 1 donated 0 Tubes PCBs Subtotal Power Systems 24x Tenergy 2/3A 1600mAh x Tenergy 9V 250mAh Power Supply Subtotal Grand Total

92 Mass Budget System Item Mass (g) Quantity Total Item Mass kg pounds Total Payload Mass Battery pack 1.2V battery kg pounds 9V battery Base Plate Top Plate Nickel Tabs Total Center of Gravity Required Level 2 Base Plate cm inches Reservoir X 0 ±0.5 0 ±0.5 Power Supply Y 0 ±0.5 0 ±0.5 Wheatstone Z ± ±0.5 Arduino Current Mux Shield X Accelerometer Y Wiring Z Total

93 Mass Budget Experiment Item Mass (g) Quantity Total (kg) Total (lbs) Stage 1 Piston Cylinder Bolt Nut Sorbothane Plate Total Stage 2 Plates Sorbothane Sorbothane Tabs Bolt Nut Total

94 Mass Budget Experiment Housing Cap Brace Base EHD Thermal sheet Hex screw elbow joint power port pin connector Total Misc Hose nut All-thread middle AT Total

95 Power Budget Device Voltage (V) Current Draw (ma) Time Running (min) mah Arduino XYZ Accelerometer Pressure Sensor Temp sensor OpenLog MUX Shield Subtotal Total Available 500 Device Voltage (V) Current Draw (ma) Time Running (min) mah WheatStone Bridge Circuit Power Supply EHD Components Thermal heaters Flow meter Subtotal Total Available 1600

96 Questions?

97