Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived. The computational fluid dynamics was used to analyze the flow features of the sloping U-shape not...Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived. The computational fluid dynamics was used to analyze the flow features of the sloping U-shape notch on the spool, such as mass flow rates, flow coefficients, effiux angles and steady state flow forces under different operating conditions. At last, the reliability of the mathematical model of the flow area for the sloping U-shape notch orifice on the spool was demonstrated by the comparison between the orifice area curve derived and the corresponding experimental data provided by the test. It is presented that the bottom arc of sloping U-shape notch （ABU） should not be omitted when it is required to accurately calculate the orifice area of ABU. Although the theoretical flow area of plain bottom sloping U-shape notch （PBU） is larger than that of ABU at the same opening, the simulated mass flow and experimental flow area of ABU are both larger than these of PBU at the same opening, while the simulated flow force of PBU is larger than that of ABU at the same opening. Therefore, it should be prior to adapt the ABU when designing the spool with proportional character.展开更多
The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition de...The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition delay and increase muzzle velocity of the projectile.A key component in ETC gun is the capillary plasma source.In this paper,a 2D steady state model of discharge was built by using magnetic hydrodynamics method.It took the plasma energy balance,material ablation,mass and momentum conservations in a quasi-neutral plasma region into account.Also,the effect of different compositions and PE concentration distribution were considered.In order to evaluate the validation of this model,the simulation results are compared with former works.展开更多
基金Project(51004085)supported by the National Natural Science Foundation of China
文摘Precise function expression of the flow area for the sloping U-shape notch orifice versus the spool stroke was derived. The computational fluid dynamics was used to analyze the flow features of the sloping U-shape notch on the spool, such as mass flow rates, flow coefficients, effiux angles and steady state flow forces under different operating conditions. At last, the reliability of the mathematical model of the flow area for the sloping U-shape notch orifice on the spool was demonstrated by the comparison between the orifice area curve derived and the corresponding experimental data provided by the test. It is presented that the bottom arc of sloping U-shape notch （ABU） should not be omitted when it is required to accurately calculate the orifice area of ABU. Although the theoretical flow area of plain bottom sloping U-shape notch （PBU） is larger than that of ABU at the same opening, the simulated mass flow and experimental flow area of ABU are both larger than these of PBU at the same opening, while the simulated flow force of PBU is larger than that of ABU at the same opening. Therefore, it should be prior to adapt the ABU when designing the spool with proportional character.
文摘The physical process of capillary discharge in a PE tube utilized in electro-thermal-chemical(ETC)guns was investigated.ETC guns can enhance the ignition and combustion of propellant in order to reduce the ignition delay and increase muzzle velocity of the projectile.A key component in ETC gun is the capillary plasma source.In this paper,a 2D steady state model of discharge was built by using magnetic hydrodynamics method.It took the plasma energy balance,material ablation,mass and momentum conservations in a quasi-neutral plasma region into account.Also,the effect of different compositions and PE concentration distribution were considered.In order to evaluate the validation of this model,the simulation results are compared with former works.
