Xin Lu
Yanhuang Zhou
Yonggang Yu
School of Power Engineering,
Nanjing University of Science and Technology,
Nanjing 210094, China
Experimental Study and
Numerical Simulation of
Propellant Ignition and
Combustion for Cased Telescoped
Ammunition in Chamber
1
Cased telescoped ammunition (CTA) is a kind of charge structure with projectile embed-
ded in the cartridge case. The advantages of CTA, compared with concepts using con-
ventional ammunition, are: (1) reduced charge/ammunition volume, (2) improved perfor-
mance, and (3) enhanced power and survivabillity of armament. The projectile is placed
in the control tube of the cartridge before shooting. After the primer is struck, propellant
product gases, generated by the igniter charge burning in the central igniter tube, drive
the projectile to move forward along the control tube, and then causing the main propel-
lants around the igniter tube and control tube to burn. Therefore, in the process of
interior ballistics, there is a motion of the projectile in the control tube before the pro-
jectile engraves the rifles, in contrast with the traditional ammunition. The consistency of
this motion has an important influence on the stability of CTA interior ballistic perfor-
mance. The experiments on the ignition and combustion of propellants and motion of
projectile in the control tube are carried out using a high-speed video recording system in
this study. The projectile velocity at the entrance of the rifle is obtained from the recorded
images. A two-phase flow model of CTA is also established and simulated by using the
two-phase flow method and computational fluid dynamics technology. The calculated
projectile velocity is in good agreement with the experimental data. The numerical results
show that the developed mathematical model gives the correct trend and can provide
useful calculated parameters for the structural design of CTA components.
关DOI: 10.1115/1.4001560兴
Keywords: cased telescoped ammunitions, multiphase flows, interior ballistics, numeri-
cal simulation, charge structures
1 Introduction
Cased telescoped ammunition 共CTA兲 is a kind of charge struc-
ture with projectile enclosed, or telescoped, within the cartridge
case completely. The advantages of CTA, compared with concepts
using conventional ammunition, are: 共1兲 reduced charge/
ammunition volume, 共2兲 improved performance, and 共3兲 enhanced
power and survivabillity of armament. Because the projectile is
embedded inside the cartridge case completely, the length of am-
munition is much shorter than the conventional ammunition at
identical caliber. Such an ammunition yields a reduction in bulk
volume of 30%. The regular cylindrical shape of the CTA car-
tridge simplifies the cannon by virtue of the “push-through prin-
ciple” of operation; its compactness and modularity foster elegant
integration solutions. By virtue of the unique rotating chamber
functionality, the weight and volume of the CTA weapon are de-
creased, and furthermore, its firing rate can be increased. Espe-
cially, in terms of existing systems, the CTA approach means ex-
isting turrets can be adapted with relative ease to accommodate
bigger caliber weapons without having to scrap the whole portion
of the turret dedicated to ammunition feed to enhance the power
and survivabillity of the armament. At present, researches in the
technology of cased telescoped ammunition have been made by
many ballistic scholars in the United States, England, France,
Russia, and China 关1–7兴. Giat Industries, a French company, has
developed the 45M911 45 mm CTA gun with an adjustable rate of
fire from 100 rds/min to 400 rds/min. The 40 mm cased tele-
scoped weapon system 共40 mm CTWS兲, a firing platform with
low center of gravity and light weight, developed by the CTA
International 共CTAI兲, a 50:50 joint venture company formed by
Giat Industries 共France兲 and Royal Ordnance 共England兲, is, as
demonstrated, compact enough to be accommodated in the turrets
of an existing Bradley fighting vehicle 共BFV兲关2兴. A complete
105-round mission load, linkless feed system of the 40 mm
CTWS can fit in the same inner spaces of the BFV, which are
originally occupied by that of the 25 mm Bushmaster weapon
system. Additionally, a newly 45 mm CTA gun developed by Rus-
sia is maybe equipped for its BMP-3 fighting vehicle.
The CTA system discussed in this study consists of the cased
telescoped ammunition, the gun barrel, and the rotating chamber.
The main difference of this system with a classical gun system is
that the rotating chamber is not part of the barrel. It is designed to
become a mobile assembly, rotating around an axis vertical to the
barrel, in order to eject the case remaining from the previous firing
and load a fresh round for the next shot. The seal system between
the front and rear end of the rotating chamber and gun system has
also been studied and is able to sustain high pressure of up to 450
MPa 关5,7兴. Because the whole ammunition is initially placed in
the rotating chamber, the projectile begins to be accelerated in the
chamber, and already has a velocity when it begins to engrave in
1
Paper No. ISB ’10 01-006.
Contributed by the Applied Mechanics Division of ASME for publication in the
J
OURNAL OF APPLIED MECHANICS. Manuscript received July 30, 2009; final manuscript
received February 4, 2010; accepted manuscript posted April 9, 2010; published
online May 17, 2010. Assoc. Editor: Bo S. G. Janzon.
Journal of Applied Mechanics SEPTEMBER 2010, Vol. 77 / 051402-1Copyright © 2010 by ASME
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