The Crea(on, Analysis, and Verifica(on of a Comprehensive Micro-‐Ion Thruster Model Seminar Presenta(on Max Bodnar March 2015 1 Thesis Goals • The crea(on of a comprehensive mathema(cal model of an ion thruster – Included submodels: Physical, Magne(cs, Electrosta(cs, Plasma physics, Power deposi(on • Analyze the performance and characteris(cs of the models – Run op(miza(on on the models to iden(fy solu(ons to the models with increased performance • Verify the results of the models – Use previous theses, NSTAR and NEXT data, and new test data to verify the models and results MiXI Background • MiXI – Miniature Xenon Ion Thruster – Originally developed by Dr. Wirz (UCLA) in 2001 – CalPoly-‐V1 created in 2009 for thermal tes(ng – CP-‐V2 created in 2011 for opera(onal tes(ng – CP-‐V3 created in 2012 implemented a hollow cathode tube (current model) • Tested for performance by Knapp and for thermal proper(es during opera(on by Parker MiXI Thruster – Physical Model • Thruster Assembly – 3 cm diameter x 3.3 cm tall discharge chamber – Contains anode pieces, grids, magnet arrays, mounts, and ceramic isolators • Hollow Cathode Assembly – Barium impregnated tungsten insert – Consists of a heater core, graphite keeper, chassis, fuel inlet, and ceramic isolators Discharge Chamber – Magne(cs Model • Designed in FEMM (Finite Element Method Magne(cs) – Uses the physical model of from Solidworks to build the edges and points – Material proper(es and magne(c characteris(cs assigned in FEMM • 3 Ring-‐Cusp configura(on – AHempts to provide two dis(nct areas within the chamber • High strength near cusps • Low strength uniform along the center • Samarium-‐Cobalt grade 27 magnets – 3mm (r) x 1mm (h) disk magnets – 11,000 G surface strength – 325O C maximum temperature Discharge Chamber – Magne(cs Model Discharge Chamber – Magne(cs Model Magne(cs Model Configura(ons Magne(cs Model Configura(ons Magne(cs Model Configura(ons Electrosta(c Model • Designed in FEMM (Finite Element Method Magne(cs) – Uses the physical model of from Solidworks to build the edges and points – Material proper(es and magne(c characteris(cs assigned in FEMM • Other stuff about the electrosta(cs model, this one is much more simple and didn’t vary with configura(ons, just show sample configura(on with the beam poten(al high Plasma Physics Model • Can control only a few inputs to the real thruster, the code was wriHen to emulate that restric(on • Thrusters have throHle points governed by the beam current Ib and mass u(liza(on ηm – This throHle point value is achieved by altering the inputs available to the user: Fuel mass flow, Discharge current Id, and Keeper current Ik – Performance characteris(cs can be altered and rely on the physical and electromagne(c configura(on (from FEMM) – All other values for the plasma model are solved internally • • • • Electron temperature TeV Plasma poten(al φ Plasma densi(es ne,i,0 Discharge loss ηd Plasma Physics Model • The outputs from Electron Temperature and Plasma Discharge submodels are used in the Power calcula(ons – Calculates Thrust, Isp, Beam power, Total power, Electrical efficiency ηe, Dissipated power, Thrust to power ra(o, Total efficiency ηT • Plasma physics model set up as input to fmincon in Matlab – Able to op(mize around any number of variables – Used to calculate the op(mum solu(on for a given physical configura(on Plasma Physics Model Output • Sample output from code and op(mizer • Compare in table the performance characteris(cs from the previous thesis and what I get from the op(mizer – Might need to do some work on the op(mizer to prevent always pushing the boundaries on some supplies • Total efficiency, plasma parameters, set points throHle points Power Deposi(on – Thermal Model • Talk about the sinks of power, look at that thermal power paper again, • Fix thermal code and replicate that table type output with my code and display that here • Talk about how the output of this code is more of a verifica(on and numbers should match what comes from the plasma model in some points and the power model in others • Talk about how much of what I was trying to do was reduce the en(re thermal load on the system so the thruster can run at steady state since the previous theses had to stop aier a few minutes of tes(ng • Discuss and use the next slide or so to show thermals from Parker Thermal model output • My data comparisons • Tabular output • Keeping this picture because I might need it for parkers graph Photo courtesy of Sam Parker Thermal Test Results -‐ Parker Photo courtesy of Sam Parker Tes(ng • Tes(ng results and comparison with plasma parameters from models and power levels to power code • More to go here… • Langmuir tes(ng, some langmuir sweeps and results table comparison of parameters • Will also want to have a table with differences between configura(ons that I have data for (currently only 2 L) • Results of tes(ng when trying to run op(mum code values and comparison to theori(cal Tes(ng s(ll • Tes(ng stuff Future work • More tes(ng and data acquisi(on • Compare configura(ons through tests and code • Try to get op(mal run solu(on for this thruster • Maybe try to get maximum thrust/power effect from the thruster if I can and I get ambi(ous Summary/Comple(on of Goals • Sort of a thesis summary here • Did I complete the goals I was trying to • What did I not, what s(ll needs work?
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