Ram Accelerator

Published on 19 May 2022. Written by Bheru Singh

About the project

A ram accelerator is a device for accelerating projectiles to very high speeds. It uses jet-engine-like propulsion cycles based on ramjet or scramjet combustion processes. Application mainly in non-rocket spacelaunch with this technology.

It consists of a long tube filled with combustible gases with a frangible diaphragm at either end to contain the gases. The projectile is fired by a light-gas gun or railgun supersonically through the first diaphragm into the tube.

The projectile burns the gases as fuel, because it is shaped like a ramjet or scramjet core, and accelerates under jet propulsion. Scramjet projectiles were tested in the HARP project

In a normal ramjet, air is compressed between a spike-shaped centerbody and an outer cowling, fuel is added and burned, and high speed exhaust gases are expanded supersonically out of the nozzle. This creates the thrust which is required for travelling at very high speeds

In a ram accelerator, a projectile having a shape similar to the ramjet centerbody is fired using a conventional gun, into the accelerator barrel, causing compression between the projectile and the barrel's walls.

The barrel contains a pre-mixed gaseous fuel-air mixture. As the ram accelerator projectile compresses the fuel-air mixture, it is ignited and the combustion is stabilized at the base of the projectile

The resulting pressure differential generates a prodigious amount of thrust that can accelerate projectiles to in-tube Mach numbers greater than 8. Multiple stages with propellants with different sound speeds are used to maintain high performance

Membranes or diaphragms that are easily punctured by the projectile are used to isolate the propellant stages. Each section is filled with a different fuel-air mixture chosen so that later sections have higher speeds of sound

Ram can be maintained at Mach 3–5 during its entire acceleration period. Ram accelerators of supersonic combustion modes can generate higher velocities like Mach 6-8 due to the ability to combust fuel that is still moving at supersonic speed.

The chief advantage of a ram accelerator over a conventional gun is its scalability. A projectile with ram accelerator is propelled primarily by the pressure generated by the reaction of the propellant gases burning just behind the projectile.

It leads to a constant pressure on the gun and the projectile. Therefore a far longer barrels are possible than conventional guns, while still delivering a strong constant acceleration to the projectile.

The hydrogen core ram accelerator is a steel tube divided into two parts: the part near the axis is filled with hydrogen, while the outer part is filled with a mixture of fuel, oxidizer, and diluent.

Ablation and premature detonation are reduced by immersing the projectile in hydrogen. Annular or helical dividers also prevent premature detonation.Balloon ram accelerator, Gas vortex ram accelerator,Powder vortex ram accelerator are its types

An Explosive ram accelerator has the hydrogen core. The projectile is propelled by a high explosive. Plastic foam protects the steel tube from the explosion. The explosive ram accelerator is more expensive than the hydrogen core ram accelerator. Disposable designs forgo the foam to achieve higher hydrogen pressure.

Kit required to develop Ram Accelerator:

Technologies you will learn by working on Ram Accelerator:

Ram Accelerator

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