Electromagnetic Railgun

Project Title

Electromagnetic Railgun

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

Electromagnetic Railgun is an emerging technology. A railgun follows basic principle of Faraday’s law of electromagnetic induction, typically invent as a weapon, which uses electromagnetic force to launch & accelerates high velocity projectiles. The projectile usually does not contain explosives, EM Railgun uses its projectile's high speed, mass, and kinetic energy to inflict damage and not rely on explosive.

The EM Rail gun is an entirely electrically powered electromagnetic projectile launcher. It is an electrical gun that uses pairs of metallic rails to accelerate a conductive projectile, following same basic principle of homopolar motor.

Conventional launchers use high pressure inside the barrel to accelerate a projectile. Conventional launchers generate such high pressure inside the barrel using expansion of gases by combustion process, but due to expansion, limits of gas achieving high velocity becomes a constraint. Because of these restrictions, projectiles launched from a conventional gun can hardly reach a velocity up to 1300m/s.

Using EM Railgun, velocity of approximately 20,000 - 50,000m/s can be achieved theoretically, while velocity range of 6000 – 7000m/s has been achieved practically. Railgun’s such capabilities make it prudent future weapon for shooting long range targets.

Apart from its application as a weapon its mechanism can be used to launch space ship or space rockets as well.

Working

Electromagnetic Railgun consists of two parallel metallic rails which are distant from each other and there is air gap between them. To provide high current there is also a current source. In this project capacitor bank is used to provide large amount of current in short instance of time. Both rails connect with capacitor bank one from positive and from ground. When projectile came in contact with both rails and filled air gap, current starts flowing from it that results magnetic force to produce in rails due to the Lorentz Force, the projectile is pushed out of the barrel with high velocity.

As the bullet move in barrel the density of magnetic field increases which causes the projectile to move with high velocity and covers long distance.

Project Objectives

Electromagnetic Railgun as its name show works on two rails and it is completely electrically powered projectile launcher. Other conventional launchers required many mechanical works involved and many combustions of gases to launch a projectile. These mechanical work and combustion of gases cause many limitations in increasing the conventional launcher projectile speed and range.

While on the other hand electromagnetic Railgun is completely electrically powered projectile launcher required only electrical power to launch a projectile. So, it is easy to achieve Mach 5 to Mach 7 Speed with electromagnetic Railgun. With its speed its range is also multiple times greater than conventional projectile launcher such as EM railgun is much more effective than Pakistan existing ABABEEL & HATF 1 missile system in terms of speed and range.

Normally, a conventional launcher is used to target area under 100km – 140km, but to target area more than 140km, missiles are used which are more costly because they required proper engine mechanism for flight. So, to overcome this issue the researchers are working on EM railgun which provides speed of Mach 5 to Mach 7 and can hit the target over long distance up to 300km.

Objective of EM railgun is also to achieve high rate of firing, conventional projectile launcher has relatively less fire rate than EM (Electromagnetic) Railgun.

Project Implementation Method

Our Project implementation is divided into two phases:

1. Mathematical Calculation
2. Practical implementation

Mathematical calculation:

In first phase, I complete a literature review and, on that basis, completed mathematical analysis.

In which we analysis on following questions:

• How much minimum magnetic Field required to launch a certain specification (mass, resistivity etc) of projectile?
• How much minimum current and voltage required to launch a certain specification (mass, resistivity etc) of projectile?

To get required current we use HV electrolytic capacitors which provide required current in short period of time, therefore done mathematical analysis on how much capacitor value required.

Practical Implementation:

For second phase that is practical implementation, we design a capacitor bank of HV electrolytic capacitors which is used to supply a required current instantaneously. Above that capacitor there is the rails setup which provide mechanism to launch our projectile.

On rails we used heavy resistors to discharge our capacitors in case when our EM railgun is in not working.

We are also considering to install capacitor voltage monitoring system to control or monitor the amount voltage charged in capacitor while charging.

Hardware

A capacitor bank of HV capacitors would be used to supply the required current. There is a barrel that would provide the launch mechanism of projectile.

Hardware includes:

1. Capacitor Bank
2. Steel Plates
3. Copper Rails
4. Capacitor Bank charging unit
5. Conductive Projectile

Benefits of the Project

Benefits of EM Railgun are as follows:

As EM Railgun has high speed and long target engagement capability, EM Railgun also have rapid firing rate. So, it can be used in following sectors:

1. EM Railgun can be used in NAVY warship.
2. EM Railgun can be used in NAVY Submarines.
3. EM Railgun mechanism used in ARMY tanks.
4. EM Railgun can be used for artillery.
5. EM Railgun can be used in Anti-Missile Defence System because its engagement time is less and it has Mach 5 – Mach 7 Speed.
6. Apart from all its application in Defence Sector it can be used in launching Space Rockets / Space ships 

Technical Details of Final Deliverable

Literature Review & Analysis: As in start of project I do detail literature review behind the Electromagnetic Railgun. Literature review consist of Electromagnetic Rail working principle, its scope and how solution works.

By applying different laws, I found following outcomes that accomplish working principle.

Following are the end results of calculations.

          …………  Minimum magnetic field required to start projectile from rest

               …………  Minimum Current required to start projectile from rest

               …………  Minimum Voltage required to start projectile from rest

How speed gets increase with increase in distance within the rail?

So when t=0,   = 0

So, I, B, F= maximum

As the bar/bullet speed up  

Then,                     

         

         …………  relationship for length of Rails.

             …………  relationship for the total amount of required Capacitance.

Implementation: 2nd stage is about implementation of project by considering these calculations, for this purpose I bought HV electrolyte capacitor of specification of 3300MFD, 450Vdc and make a capacitor bank and connect them in parallel. To make barrel we use to conductive rails of copper.

The reason of selecting copper is given below.

Material	Melting Temperature (°C)	Density (Kg/m^3)	Conductivity (?-m)^-1	Specific Heat (j/Kg-°C)
Tungstun	3410	19,250	1.79*10^7	134
Copper	1084	8960	5.8*10^7	385
Aluminium	660	2720	3.82*10^7	900
Tentalum	2996	16,600	7.7*10^6	150.62

By above analysis the desired material for barrel is copper.

MaterialTungstunCopperAluminiumTentalumFinal Deliverable of the Project Hardware SystemCore Industry SecurityOther IndustriesCore Technology OthersOther TechnologiesSustainable Development Goals Industry, Innovation and InfrastructureRequired Resources

Elapsed time in (days or weeks or month or quarter) since start of the project	Milestone	Deliverable
Month 1	Design Documentation	Initial discussion about project and discuss deliverables
Month 2	Design Documentation & Presentation	completed design documentation and start literature review
Month 3	Literature Review	Follow different literature for mathematical analysis
Month 4	Literature Review	Follow different literature for mathematical analysis
Month 5	Early discussion on Circuit analysis and Designing	Discussion on Circuit analysis and Designing
Month 6	Gathering Components	Purchasing HV Capacitors, Copper Rails, etc.
Month 7	Gathering Components and Implementation	Assembling the components to make protype
Month 8	Final Documentation of prototype and toping the prototype	Final Documentation and Presentation