TECHNOLOGY AREA(S): Weapons
OBJECTIVE: Develop novel muzzle brake structures for extended range cannon artillery systems that reduce mass while maintaining or improving recoil reduction, signature management, durability, and operator safety.
DESCRIPTION: Given the Army’s Long Range Precision Fires priority, a need exists for novel and innovative muzzle brakes capable of supporting the new extended range cannons and sabot, direct, and indirect munitions currently under development. High pressure waves produced within gun barrels during projectile acceleration have negative impact upon the surrounding environment due to muzzle blast flow fields exiting the barrel. The negative consequences, such as recoil and noise production, can be alleviated by redirecting propellant gases. Muzzle brakes have been used for decades to efficiently redirect propellant gas, resulting in effective performance gains. However, recent advances in multi-disciplinary design optimization and additive manufacturing techniques show promise for muzzle brake weight reduction while maintaining the favorable flow field response and resistance to the resulting thermal and pressure loading
Muzzle brakes are subject to complex loading due to shock wave characteristics from both the propellant explosion and its interaction with the projectile. Typical pressure and thermal conditions in the vicinity of the barrel exit have been found to be as much as 10-12 ksi and 2000 K, respectively. These conditions are dynamic and vary based on the firing inclination of the gun barrel. Muzzle brakes are also subjected to material degradation due to collisions with small particles exiting the gun barrel, such as solid propellant grains that did not undergo combustion. Due to these harsh flow environments and material performance requirements, muzzle brakes used in current artillery systems can be heavy.
This topic seeks to develop novel muzzle brake aerodynamic designs and structures which minimize the overall mass of the artillery system without compromising performance. A variety of analysis methods and performance validation techniques should be performed to achieve significant mass reduction in order to determine the optimal layout of material and aerodynamic design of flow redirection channels or baffles. The objective for this effort is to achieve 30 percent weight reduction compared to conventional muzzle brakes.
PHASE I: Model and simulate the operational performance of proposed muzzle brake designs that meet the weight reduction requirements. Simulate mechanical wear over the lifecycle of the brake. Conduct an analysis of alternatives to select the prototypes to be delivered in phase II. Perform a preliminary validation of the manufacturing concept, and prepare initial production cost estimates for the designs under consideration.
PHASE II: Produce at least one prototype muzzle brake to be tested on a large caliber army platform identified during the phase I effort. Perform live fire tests with either a government-furnished weapon system or on a representative test fixture. Extrapolate wear to the muzzle brake using computer modeling or through simulation on a physical a test fixture. Document recoil, acoustic and optical signature, and muzzle blast (temperature and atmospheric pressure profile). Perform final design refinements. Model performance and make refinements to the prototype design.
PHASE III: Conduct a live fire demonstration of the final prototype in an operational environment with involvement from the prime contractor for the weapon system. Explore potential small arms applications for both military and private sector customers.
REFERENCES: 1: Carson, Robert A., and Onkar Sahni. "Scaling Laws for the Peak Overpressure of a Cannon Blast." Journal of Fluids Engineering 139.2 (2017): 021204.2: Carson, R. A., and O. Sahni. "Study of the relevant geometric parameters of the channel leak method for blast overpressure attenuation for a large caliber cannon." Computers & Fluids 115 (2015): 211-225.3: Fansler, Kevin S., et al. A parametric investigation of muzzle blast. No. ARL-TR-227. ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD, 1993.KEYWORDS: Muzzle Device, Muzzle Brake, Fluid Dynamics, Acoustics, Artillery, Cannon
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