Electromagnetic Expulsion from an Outer Tube Naval Undersea Warfare - - PowerPoint PPT Presentation

Electromagnetic Expulsion from an Outer Tube

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 Naval Undersea Warfare Center [NUWC]

Final Presentation Team 1915

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

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 Unmanned Underwater Vehicles are traditionally launched by pumping water behind a payload and using that force to expel the object from a tube

Background

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 Total 30 35 22 22

Coilgun Electromagnetic Principles

Magnetic Field Induced by Current on a Straight Wire Magnetic Field Induced in a Solenoid Faraday’s Law of Induction

N = Number of Coil Turns dΦ/dt = Change in magnetic flux over the change of time B = Magnetic Field μo = Magnetic Permeability in Vacuum l = Length of the Coil I = Current (Amps)

https://physics.stackexchange.com

Original Coilgun Specifications

Number

• f Turns

Radius (inches) Length (inches) Inductance (mH) 200 2.5 5 5.01

N = Number of Turns A = Area of Solenoid μo = Magnetic Permeability l = Length of Solenoid L = Inductance of Solenoid

Calculation of Magnetic Field and Force

Current (Amps) Armature Radius (inch) Magnetic Field (B) Force (N) 60 1 ~0.1T ~7.97

B = Magnetic Field A = Area of the Armature μo = Magnetic Permeability in Vacuum F = Force on Object within Coil

Why is a Pulse of Current Needed?

https://www.youtube.com/watch?v=PMU9TQUDhow

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

Circuit Design

ID = Diode Current Is = Saturation Current VD = Voltage Across the Diode n = Ideality Factor VT = Thermal Voltage

Prototype Design

Coil V1 and Coil V2

➢ 5” Coil Length ➢ N = 200 Turns ➢ Ten 50V 6800μF Capacitors ➢ Weak and dispersed magnetic field ➢ 3” Coil Length ➢ N = 400 Turns ➢ Ten 100V 6800μF Capacitors ➢ Much more concentrated field with higher strength

Recalculated Forces - L and I

Inductance (Henries) Capacitance (Farads) Charge (Coulombs) Voltage (Volts) Max Current (Amps) .0334 .068 6.8 100 ~140 (lossless) Number

• f Turns

Radius (inches) Length (inches) Inductance (H) 400 2.5 3 .0334

Recalculated Forces - B and F

Current (Amps) Armature Radius (inch) Magnetic Field (B) Force (N) ~40 0.725 0.15T ~18 Current (Amps) Number of Turns Max Magnetic Field (B) ~40 400 ~0.37T Old Force (N) ~8 Old Max Magnetic Field (B) ~0.23T

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

➢ Wheels eliminate a substantial amount of friction ➢ Tracks stabilize the armature ➢ Magnetic field shielding observed during testing ➢ Shielding prevents the launching of the armature ➢ Same level of friction as steel rails ➢ Armature has a high instantaneous velocity ➢ Negligible shielding observed ➢ Recommended for final underwater design Steel Rails 3D Printed Rails

Wet Testing Rig Construction

Submerged Launcher Circuit Box Externals Circuit Box Internals

Wet Testing Results

Exit Velocity (ft/s)

5.2 Front View Top View Side 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?