# Accession Number:

## AD0895229

# Title:

## Significant Parameters for the Expansion of Propellant Gases in an Idealized Gun

# Descriptive Note:

# Corporate Author:

## NAVAL ORDNANCE LAB WHITE OAK MD

# Personal Author(s):

# Report Date:

## 1951-02-19

# Pagination or Media Count:

## 20.0

# Abstract:

In a previous memorandum NOLM 10819, a method was developed to calculate the muzzle velocity and acceleration of a projectile in an idealized gun. It was shown that an accurate method is available and that, given the ratio of charge mass to projectile mass, GM, the value of the excluded volume in the Abel equation of state, and the initial values of the pressure and temperature, the motion of the projectile within the gun barrel could be calculated for all values of the ratio of specific heats. The present report deals with the problem of simplifying the calculations by reducing the number of parameters to a minimum. It is shown here that for a given gas or gas mixture the problem can be formulated in such a way that the only arbitrary parameter is the ratio GM. As a result of this investigation it is possible to calculate by the method developed, a single curve giving the velocity of the projectile in the idealized gun barrel for a given value of GM. This single curve then, by a simple change of scale, yields the velocity of the projectile in the gun for different initial distances between a projectile and breech, for different values of excluded volume, and for different initial pressures and temperatures. The reduction in the calculation labor is significant.

# Descriptors:

- *GUN BARRELS
- *GUNS
- *PROJECTILES
- ACCELERATION
- COMBUSTION CHAMBER GASES
- CORRELATION TECHNIQUES
- EQUATIONS
- EQUATIONS OF MOTION
- EQUATIONS OF STATE
- GUN PROPELLANTS
- INTERIOR BALLISTICS
- MATHEMATICAL PREDICTION
- PRESSURE
- PROJECTILE TRAJECTORIES
- SPECIFIC HEAT
- TEMPERATURE
- THERMAL EXPANSION
- VELOCITY
- VOLUME
- WEIGHT

# Subject Categories:

- Ammunition and Explosives
- Ballistics