The gridless method coupled with finite rate chemistry model is employed to simulate the external combustion flow fields of M864 base bleed projectile. The fluid dynamics process is described by Euler Equation in 2-D ...The gridless method coupled with finite rate chemistry model is employed to simulate the external combustion flow fields of M864 base bleed projectile. The fluid dynamics process is described by Euler Equation in 2-D axisymmetric coordinate. The numerical method is based on least-square gridless method,and the inviscid flux is calculated by multi-component HLLC( Harten-Lax-van Leer-Contact) scheme,and a H2-CO reaction mechanism involving 9 species and 11 reactions is used. The computations are performed for the full projectile configuration of Ma = 1. 5,2,and 3. The hot air injection cases and inert cases are simulated for comparison. The numerical results show that due to the combustion in the weak region,the recirculation zone enlarges and moves downstream,the base pressure increases and the total drag force coefficient decreases. At Ma = 3. 0,the rear stagnation point shifts downstream approximate 0. 26 caliber,and the base pressure increases about 53. 4%,and the total drag force coefficient decreases to 0. 182 which agrees well with the trajectory model prediction. Due to neglecting the effects of viscosity and turbulence,there exists a certain difference at Ma = 1. 5,2. 0.展开更多
It is difficult to find the projectile when people want to get the penetration data in a hard recovery method,so a recovery system of penetration data is designed based on an ejection mode from the projectile base and...It is difficult to find the projectile when people want to get the penetration data in a hard recovery method,so a recovery system of penetration data is designed based on an ejection mode from the projectile base and a method of wired transmission,at the same time,the system was sealed with a designed sealing device,the working principle of which was introduced.Using Fluent as the simulation platform,the transient pressure of seal cavity was simulated based on the change of chamber pressure,and steady-state pressure of seal clearance and seal cavity were simulated based on the maximum chamber pressure.The sealing performance was tested by apressure test system.The results of simulation and experiment show that the maximum pressure of seal cavity is 139.4kPa when the maximum chamber pressure is 242.9MPa and the maximum temperature of gunpowder explosive gas is2 166.5K,so the sealing performance can be assured.The sealing device can be taken as a reference in sealing research on gunpowder gas at the bottom of projection.展开更多
文摘The gridless method coupled with finite rate chemistry model is employed to simulate the external combustion flow fields of M864 base bleed projectile. The fluid dynamics process is described by Euler Equation in 2-D axisymmetric coordinate. The numerical method is based on least-square gridless method,and the inviscid flux is calculated by multi-component HLLC( Harten-Lax-van Leer-Contact) scheme,and a H2-CO reaction mechanism involving 9 species and 11 reactions is used. The computations are performed for the full projectile configuration of Ma = 1. 5,2,and 3. The hot air injection cases and inert cases are simulated for comparison. The numerical results show that due to the combustion in the weak region,the recirculation zone enlarges and moves downstream,the base pressure increases and the total drag force coefficient decreases. At Ma = 3. 0,the rear stagnation point shifts downstream approximate 0. 26 caliber,and the base pressure increases about 53. 4%,and the total drag force coefficient decreases to 0. 182 which agrees well with the trajectory model prediction. Due to neglecting the effects of viscosity and turbulence,there exists a certain difference at Ma = 1. 5,2. 0.
文摘It is difficult to find the projectile when people want to get the penetration data in a hard recovery method,so a recovery system of penetration data is designed based on an ejection mode from the projectile base and a method of wired transmission,at the same time,the system was sealed with a designed sealing device,the working principle of which was introduced.Using Fluent as the simulation platform,the transient pressure of seal cavity was simulated based on the change of chamber pressure,and steady-state pressure of seal clearance and seal cavity were simulated based on the maximum chamber pressure.The sealing performance was tested by apressure test system.The results of simulation and experiment show that the maximum pressure of seal cavity is 139.4kPa when the maximum chamber pressure is 242.9MPa and the maximum temperature of gunpowder explosive gas is2 166.5K,so the sealing performance can be assured.The sealing device can be taken as a reference in sealing research on gunpowder gas at the bottom of projection.
