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Our customer specializes in developing state-of-the-art small arms and light weapons by pursuing extensive research. Gas operated weapon is a rifle where portion of propellant gases is redirected to operate reloading subassemblies. Purpose of this automation is to achieve a high rate of fire and this depends on the amount of gas redirected as well as its pressure characteristics. Thus accurate prediction of gas related parameters is most crucial for design optimization.

Numerical simulation of this problem involved bullet dynamics, gas flow through tapping, pressure built-up ahead of piston and finally, movement of piston subassembly for reloading. Zeus Numerix developed an Octree mesh based CFD solution procedure that couples moving body dynamics of gun-bullet-piston configuration. The simulations were unsteady transient in time domain. The predicted piston velocities were validated against those measured during field trials.

Flow pattern ahead & behind the bullet during firing of gun

Flow pattern ahead & behind the bullet during firing of gun

Zeus Numerix delivered a customized simulation tool that enabled customer to undertake parametric study to optimize gas reloading design. Later, the simulation tool was upgraded to exploit parallel hardware and reduce turnaround time. Thus, improvements were made to rate of fire by the client using advanced simulation technologies.