2006-2007 - Kennedy Space Center Technology Transfer Office

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Parameter Estimation of Lateral Spacecraft Fuel SloshPredicting the effect of fuel slosh on the attitude control system of a spacecraft or launchSpacecraftNutation vehicle is a very important and challenging task. Whether the spacecraft is spinning orModels moving laterally, the dynamic effect of the fuel slosh helps determine whether the spacecraftwill remain on its intended trajectory. Three categories of slosh can be caused by launchvehicle or spacecraft maneuvers when the fuel is in the presence of an acceleration field.These are bulk-fluid motion, subsurface wave motion (currents), and free-surface slosh. Each of theseslosh types has a periodic component defined by either a spinning or a lateral motion. For spinningspacecraft, all three types of slosh can greatly affect stability. Bulk-fluid motion and free-surface sloshcan affect the lateral-slosh characteristics. For either condition, an unpredicted coupled resonancebetween the spacecraft and its onboard fuel could threaten a mission. This ongoing research effortseeks to improve the accuracy and efficiency of modeling techniques used to predict these typesof fluid motions for lateral motion. Particular efforts focus on analyzing the effects of viscoelasticdiaphragms on slosh dynamics.Previous research used MATLAB SimMechanics to model free-surface fuel slosh with a simpleone-degree-of-freedom (DOF) pendulum analog. The pendulum analog modeled a spherical tankundergoing free-surface slosh created by oscillating the tank via an electric motor attached to alocomotive arm assembly. A SimMechanics model incorporating the analog of the experimentwas developed and tested. Parameters describing the simple pendulum models, such as spring anddamping constants at the pendulum hinge location and pendulum length, characterized the modalfrequency of the free-surface sloshing motion. The one-DOF model offered insights into free-surfacefuel slosh and served as a stepping stone for the present research. Using the previous experimentalsetup, we tested different liquids undergoing free-surface slosh and estimated the various pendulumparameters using MATLAB’s Parameter Estimator Toolbox.The first step was to experiment with several liquids with different viscosities in order to betterunderstand how that liquid property affects lateral fuel slosh and the resulting pendulum analogparameters. Liquids of varying viscosities and physical characteristics different from water wereused. It was assumed that for higher viscosities, the peak amplitude of the reaction force on the tankwould be lower than the values measuredwhen using water. As predicted, pendulumdamping, which determines the stiffness ofthe pendulum, was the critical parameterwhen comparing the liquids with differentviscosities. The more damped the pendulumhinge, the less peak force there was atresonance. Parameters (such as the sloshfrequency and pendulum length) remainedthe same for all liquids, regardless of theirviscosities. The SimMechanics model wasupdated and adjusted for the simulationusing different liquids. After obtainingexperimental data at three different fill levels(60, 70, and 80 percent) for both glycerineand corn syrup, the data was imported intoSimMechanics, where free-surface sloshconditions were simulated. Figures 1 and2 compare the experimental data and thesimulated data for glycerine and corn syrup atFigure 1. Glycerine: 60-percent fill level, oscillating at 1.75 Hz (unit = lbf).the 60-percent fill level.84 Fluid System Technologies
In an ongoing effort for improvement,the locomotive assembly was replacedby a state-of-the-art shaker assembly.Four diaphragms, each with a differentstiffness, were attached to the peripheryof their tanks so that the effects of sloshon each could be studied (Figure 3).These new transparent spherical fueltanks with diaphragms will be mountedon a fixture and linearly oscillated bythe shaker. The forces at the tank wall,along the axis of lateral motion, will bemeasured by a force transducer mountedon the fixture, similar to what was donewith the locomotive assembly.Diaphragms provide a substantial levelof slosh damping as a result of thecombination of viscoelastic flexing ofthe diaphragm and the increased viscouseffects at the liquid-diaphragm interface.It is assumed that, as the stiffness ofthe diaphragm increases, the pendulumdamping parameter will increase, as wasobserved on free-surface tests of fluidswith higher viscosities. The presence ofa diaphragm in the fuel tank should alsoincrease the natural frequency of the sloshbecause of the constraints imposed onthe free-surface shape. In addition, theeffective mass of liquid participating inthe sloshing will most likely be smallerthan that for a tank of the same shapeand fill level without a diaphragm. Thatis, a greater percentage of fluid willbehave as if it were attached to the tank.Figure 4 shows the new slosh test facilitydesigned, fabricated, and installed atEmbry-Riddle Aeronautical Universityto investigate the lateral sloshing ofspacecraft propellant tanks.Amplitude Out0.30.20.10–0.1–0.2–0.3Measured vs. Simulated ResponsesNew Data–0.40 1 2 3 4 5 6 7 8 9 10Time (s)Figure 2. Corn syrup: 60-percent fill level, oscillating at 1.75 Hz (unit = lbf).Figure 3. Experimental setup with the diaphragm.Contacts: James E. Sudermann , NASA-KSC,(321) 867-8447; and Keith L. Schlee, AnalexCorporation, (321) 867-4186Participating Organizations: Embry-Riddle Aeronautical University (Dr. SathyaGangadharan, Yadira Chatman, and BrandonMarsell) and Hubert Astronautics, Inc.(Dr. Carl Hubert)Figure 4. New slosh test facility at Embry-Riddle Aeronautical University.KSC Technology Development and Application 2006-200785
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ForewordSuccessful technology devel
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ContentsSpaceport Structures and Ma
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Contents (continued)Process and Hum
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IntroductionJohn F. Kennedy Space C
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Constellation SystemsSurfaceSystems
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Spaceport Structures and MaterialsK
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20181614∆ E1210Modified Sensor Be
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Initial results of the EDEM model o
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Contacts: Dr. Carlos I. Calle ,NASA
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Close examination of the corrosions
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Adhesion at Failure (psi)2500200015
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Figure 1. After 500 hours of salt f
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Contacts: Dr. Paul E. Hintze , NASA
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Figure 2. Repairs to various types
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on top of the cuvette contains the
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Figure 2. A corrugated NiTi sheet e
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The PLTD can be used to (1) calibra
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SEM images of neat MWNT fibers: (a)
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Contacts: Trent M. Smith
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Figure 1. An isometric cutaway view
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Figure 2. Quartz sand flowing in th
Page 47 and 48: Figure 2. Top images show how the e
Page 49 and 50: Sand volume fraction contour at t =
Page 51 and 52: Integrated LWRD/RVC engineering bre
Page 53 and 54: Mean relative percentage change in
Page 55 and 56: We compared the model’s predictio
Page 57 and 58: Figure 2. Three-dimensional simulat
Page 59 and 60: Figure 3. Camera calibration model.
Page 61 and 62: The sketch in Figure 2 shows alaunc
Page 63: Figure 2. Signal generator (right)
Page 66 and 67: Hail Size Distribution MappingA 3-D
Page 68 and 69: Launch Pad 39 Hail Monitor Array Sy
Page 70 and 71: Autonomous Flight Safety System - P
Page 72 and 73: The Photogrammetry CubeSpaceport/Ra
Page 74 and 75: Bird Vision SystemThe Bird Vision s
Page 76 and 77: Automating Range Surveillance Throu
Page 78 and 79: Next-Generation Telemetry Workstati
Page 80 and 81: GPS Metric Tracking UnitAs Global P
Page 82 and 83: Space-Based RangeSpace-Based Range
Page 85 and 86: Fluid System TechnologiesKSC Techno
Page 87 and 88: 0.900.850.80Discharge Coefficient,
Page 89 and 90: Composite seals for performance eva
Page 91 and 92: 140000120000100000Signal80000600004
Page 93 and 94: Contacts: Dr. Barry J. Meneghelli ,
Page 95 and 96: 60555045Comparative k-value (mW/m-K
Page 97: a compatible spacecraft model where
Page 101: Low-gravity probe prototype test.th
Page 104 and 105: Countermeasure for Radiation Protec
Page 106 and 107: Focused Metabolite Profiling for Di
Page 109 and 110: Process and Human FactorsEngineerin
Page 111 and 112: DON uses game technology to enable
Page 113 and 114: Type of mobile crane that impacted
Page 115 and 116: SALT proof-of-concept communication
Page 117 and 118: SSLM CAD model.Our design offers th
Page 119 and 120: Variables that can be integrated by
Page 121: Exploration Supply Chain Simulation
Page 124 and 125: Nanosensors for Evaluating Hazardou
Page 126 and 127: Sixty-four-Channel Inline Cable Tes
Page 128 and 129: Wireless Inclinometer Calibration S
Page 130 and 131: Generating Safety-Critical PLC Code
Page 132 and 133: Spacecraft Electrostatic Radiation
Page 134 and 135: Ion Beam Propulsion StudySpacecraft
Page 136 and 137: RT-MATRIX: Measuring Total Organic
Page 139 and 140: Appendix AKSC High-Priority Technol
Page 141 and 142: Risk Assessment ToolMission Data Fe
Page 143 and 144: Appendix BInnovative Partnership Pr
Page 145 and 146: system for the Government, using th
Page 147: tracking objects after launch, and
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2006-2007 - Kennedy Space Center Technology Transfer Office

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