Analysis of bi directional coupling characteristics in high overload soft recovery system internal ballistic

DOI:	10.11809/bqzbgcxb2024.09.004
Keywords:	air damping; internal ballistics; flow field simulation; bidirectional coupling; fluent
Abstract:	A bi directionally coupled internal ballistic simulation model was developed to investigate the influence of projectile front pressure on the internal ballistics of high overload soft recovery systems. The model includes a high pressure buffer gas in front of the projectile, which meets the criteria of a 20,000g overload index. The FLUENT software was employed to calculate the projectile’s frontal pressure, which was then integrated bidirectionally with classical internal ballistics for simulation analysis using User Defined Functions (UDF). In the context of a 5.51 kg propellant charge mass, high overload simulations were conducted on a 90 kg projectile compartment. The results indicate that a pre inflation gas pressure of 2 MPa will increase the maximum pressure in the bore by 2.32%. When the pre inflation gas pressures are 5 MPa, 8 MPa, and 10 MPa, the maximum velocity of the projectile compartment decreases by 7.32%, 12.36%, and 15.61%, respectively. For projectile compartment masses of 70 kg and 80 kg, the maximum velocities of the projectile compartments increase by 9.63% and 4.56%, respectively. The choice of different gas media has a relatively small impact on the projectile front pressure, with air being the optimal choice as the buffer medium. This paper examines the impact of pre inflation pressure, projectile compartment mass, and pre inflation gas medium on the characteristics of internal ballistics. The analysis is based on the bi directional coupling model between the projectile’s frontal pressure and internal ballistics. The findings provide theoretical references for the internal ballistics research of air damped soft recovery tests.
Published:	2024-09-30
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