In laser ignition systems, to ignite the propellant, the laser has to be transmitted into chamber through an optical window. If the optical window is destroyed by high pressure or high temperature or contaminated by the black powder residue, the ignition system will fail in further firings. The sapphire window can withstand the high pressure and high temperature of the ballistic cycle, but it is necessary to keep the window clean for the laser to transmit repeatedly. In modular charge systems or fully combustible cartridge cases, there is no place to put a shield window as in ammunition with stub base; thus a new contamination prevention method is put forward. In this method, the hydrodynamic force is used to divert the gas flow in a cavity located in the breech to avoid contact with the optical window and prevent it from being contaminated. To verify the effectiveness of this structure, a three-dimensional unsteady discrete phase model (DPM) coupled with an interior ballistic process was established. The simulation results indicated that the flow jet from the direct orifice was diverted, and particle debris did not contaminate the optical window due to the hydrodynamic force. Various factors influencing the contamination prevention effect were discussed, and the structure parameters were optimized.

References

References
1.
Zhang
,
H. S.
,
Zhang
,
X. B.
,
Yuan
,
Y. X.
, and
Yang
,
J. Y.
, 1997, “
Survey of the Technology of Laser Ignition in Large-Caliber Guns
,”
J. Ballistics
,
9
(
1
), pp.
90
95
.
2.
Barrows
,
A. W.
,
Forch
,
B. E.
,
Beyer
,
R. A.
,
Cohen
,
A.
, and
Newberry
,
J. E.
, 1993, “
Laser Ignition in Guns, Howitzers and Tanks: The LIGHT Program
.” AD–A261049.
3.
Zhang
,
X. B.
,
Yuan
,
Y. X.
,
Yang
,
J. Y.
, and
Zou
,
R. R.
, 1999, “
Experimental and Numerical Study on the Laser Ignition Performances
,”
Proceedings of the 18th International Symposium on Ballistics
,
San Antonio, TX
.
4.
Wang
,
H.
,
Huang
,
M.
, and
Shao
,
Z. J.
, 2000, “
A Study on the Laser Multi-Point Ignition of Guns
,”
ACTA Armamentarii
21
(
2
), pp.
101
104
.
5.
Zhang
,
X. B.
,
Yang
,
J. Y.
, and
Xie
,
Y. S.
, 1996, “
Experimental Studies of Laser Multipoint Uniform Ignition
,”
J. Ballistics
11
(
2
), pp.
78
80
.
6.
Yu
,
W.
, and
Zhang
,
X. B.
, 2010, “
Aerodynamic Analysis of Projectile in Gun System Firing Process
,”
ASME J. Appl. Mechan.
,
77
(
5
), pp.
51406.1
51406.8
.
7.
Mark
,
B.
, 1998, “
Thermo Response of Sapphire to Propellant Combustion
.” AD-A344626.
8.
Yuan
,
Y. X.
, and
Zhang
,
X. B.
, 2005,
Multiphase Hydrokinetic Foundation of High Temperature and High Pressure
,
Publishing Company of Harbin Institute of Technology
,
Harbin
.
9.
Howard
,
S. L.
,
Chang
,
L.-M.
, and
Grosh
,
J.
, 1996, “
Hydrodynamic Breech Window Design Concept for Laser Ignition of Large-Caliber Guns
.” AD-A310749.
10.
Gu
,
K.Q.
,
Qian
,
L. F.
, and
Hou
,
B. L.
, 2000, “
Assembly Level Finite Element Analysis of Breech Mechanism of Gun
,”
J. Nanjing Univ. Sci. Technol.
,
24
(
5
), pp.
414
417
.
11.
Gu
,
K. Q.
, and
Yang
,
J. R.
, 2003, “
FE Analysis of Strength and Obturating Performance of a Floating Gun Breech Obturator Structure
,”
J. Ballistics
15
(
1
), pp.
17
21
.
12.
Kang
,
L. Q.
, and
Guo
,
L. J.
, 2006, “
Simulation of Windblown Sand Movement by Discrete Particle Model
,”
J. Eng. Thermophys.
27
(
3
), pp.
441
444
.
13.
Luo
,
X. L.
, and
Gu
,
Z. L.
, 2007, “
Study of Aero Dispersion in Urban Street Canyon Based on DPM Model
,”
J. Graduate School Chin. Acad. Sci.
24
(
5
), pp.
578
583
.
14.
Beyer
,
R. A.
,
Chang
,
L.-M.
, and
Forch
,
B. E.
, 1996, “
Laser Ignition of Propellant in Closed Chambers
,” AD-A306949.
15.
Hussain
,
G.
, and
Rees
,
G. J.
, 1990, “
Combustion of Black Powder. Part 1: Thermo-Analytical Studies
,”
Propellants, Explos., Pyrotech.
15
, pp.
43
47
.
16.
Sambamurthi
,
J. K.
, 1995, “
Plume Particle Collection and Sizing From Static Firing of Solid Rocket Motors
,” AIAA Paper No. 95-2590.
17.
Williams
,
A. W.
,
Brant
,
A. L.
,
Kaste
,
P. J.
, and
Colburn
,
J. W.
, 2006, “
Experimental Studies of the Number 41 Primer and Ignition of 5.56-mm Ammunition
,” ADA456635.
You do not currently have access to this content.