Final Presentation Team 1915 Electromagnetic Expulsion from an Outer Tube Naval Undersea Warfare Center [NUWC] ECE Team: Christian Corwel, George Zoghbi, Stevan Webb ME Team: Menna Elfouly, Austin Gallimore, & Liam Perkins Mentors: Dr. James LeBlanc, Mike Sheahan Faculty Advisor: Dr. Abhishek Dutta
Presentation Outline 1. Overview and Requirements 2. Considered Design Concepts 3. Design Modeling and Simulation 4. Initial Testing/Redesign and Recalculation 5. Physical Testing Results 6. Timeline and Budget 7. Final Thoughts
Project Overview & Requirements Unmanned Underwater Vehicles are traditionally launched by pumping Background water behind a payload and using that force to expel the object from a tube Electromagnetic Launchers are the Future More efficient than traditional launchers ❖ Require less space on vessel ❖ Capable of producing high exit velocities ❖ ❖ Higher reliability Deliverables ❖ Fully functional underwater prototype ❖ Calculations of magnetic force on payload Simulations of circuit behavior and magnetic field ❖ https://en.wikipedia.org/wiki/Torpedo_tube
Design Assessment Railgun Coilgun EMAL MHD Requirements Score (1-5) Score (1-5) Score (1-5) Score (1-5) Simplicity of Design 4 5 2 1 Simplicity of Circuit 4 5 3 1 Size/Weight Constraints 3 4 3 3 Power Required 3 3 2 2 Launch size flexibility 4 4 3 5 Reliability 3 5 3 4 Exit Velocity 5 4 4 2 Cost Effective 4 5 2 4 30 35 22 22 Total
Coilgun Electromagnetic Principles Faraday’s Law of Induction Magnetic Field Induced in a Solenoid N = Number of Coil Turns dΦ/dt = Change in magnetic flux over the change of time Magnetic Field Induced by Current on a B = Magnetic Field https://physics.stackexchange.com Straight Wire μ o = Magnetic Permeability in Vacuum l = Length of the Coil I = Current (Amps)
Original Coilgun Specifications N = Number of Turns A = Area of Solenoid μ o = Magnetic Permeability l = Length of Solenoid L = Inductance of Solenoid Number Radius Length Inductance of Turns (inches) (inches) (mH) 200 2.5 5 5.01
Calculation of Magnetic Field and Force B = Magnetic Field A = Area of the Armature μ o = Magnetic Permeability in Vacuum F = Force on Object within Coil Current Armature Magnetic Force (Amps) Radius (inch) Field (B) (N) 60 1 ~0.1T ~7.97
Why is a Pulse of Current Needed? 1. Force pulls payload towards the center of the coil 2. Constant current will not launch the payload 3. A high current pulse will launch the payload https://www.youtube.com/watch?v=PMU9TQUDhow
Circuit Design I D = Diode Current I s = Saturation Current V D = Voltage Across the Diode n = Ideality Factor V T = Thermal Voltage
Prototype Design
Coil V1 and Coil V2 3” Coil Length ➢ 5” Coil Length ➢ ➢ N = 400 Turns N = 200 Turns ➢ Ten 100V 6800μF Capacitors ➢ Ten 50V 6800μF Capacitors ➢ ➢ Much more concentrated field with Weak and dispersed magnetic field ➢ higher strength
Recalculated Forces - L and I Number Radius Length Inductance of Turns (inches) (inches) (H) 400 2.5 3 .0334 Max Inductance Capacitance Charge Voltage Current (Henries) (Farads) (Coulombs) (Volts) (Amps) ~140 .0334 .068 6.8 100 (lossless)
Recalculated Forces - B and F Old Max Current Max Magnetic Magnetic Number of Turns (Amps) Field (B) Field (B) ~40 400 ~0.37T ~0.23T Current Armature Magnetic Force Old Force (Amps) Radius (inch) Field (B) (N) (N) ~40 0.725 0.15T ~18 ~8
Dry Test Rig Construction Circuit Components ❖ ➢ 16Ga Copper Enameled Wire 100 VDC, 6800 uF Electrolytic Capacitors ➢ ➢ 100 A SPST Switching Relay 100 A High Current Rectifier Diode ➢ Capacitors and Batteries wired into banks ❖ Allow for more efficient storage ➢ Can be easily switched out in case of failure ➢ ❖ Circuit wired with safety redundancies Charging source is disconnected during firing ➢ phase. Low chance of switching errors ➢
Ski Armature Testing Results Strong magnetic field produced ❖ Armature moves several inches down the tube ➢ Able to launch UUV at low velocity ➢ High coefficient of friction still observed ❖ Armature speed limited by plastic skis ➢ Force exerted by ski legs on tube walls is high ➢ Not recommended for final design ➢ Measured Force ( lbf ) 1.8
Wheel Armature Testing Results 3D Printed Rails Steel Rails ➢ Wheels eliminate a substantial amount of friction ➢ Same level of friction as steel rails Tracks stabilize the armature Armature has a high instantaneous velocity ➢ ➢ ➢ Magnetic field shielding observed during testing ➢ Negligible shielding observed Shielding prevents the launching of the armature Recommended for final underwater design ➢ ➢
Wet Testing Rig Construction Circuit Box Externals Circuit Box Internals Submerged Launcher
Wet Testing Results Front View Exit Velocity (ft/s) 5.2 Side View Top View
Timeline
Project Budget Breakdown
Final Thoughts and Demo Day Plans Successfully completed the deliverables desired by NUWC ❖ Successfully coordinated as a dual-major team ❖ Stayed under budget ❖ Will be finalized for Demo Day ❖ Functional launcher will be displayed and demoed to our mentors from NUWC ➢ ➢ Completed poster will also be displayed to outline the project
Thank You Any Questions?
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