Parametric study of a projectile launched by a compressed air cannon

The principle of the compressed air cannon is that compressed air in the reservoir expands rapidly to propel the projectile. Previous studies assume that the tube pressure in front of the projectile is constant because the tube pressure was too low compared to the compressed air pressure in the reservoir. However, when the projectile actually travels in the tube, a compression wave is generated in front of the projectile. In this study, the theoretical prediction for the velocity of the projectile was performed using the tube pressure in front of the projectile affected by the compression wave as a variable. The results show that the maximum velocity decreases compared to previous studies. This difference from the constant tube pressure assumption cases becomes larger as the maximum velocity of the projectile increases. The theoretical prediction considering the compression wave shows a more realistic deceleration than when the tube pressure is constant.