Light screen velocity measuring method with unique advantages has been widely used in the velocity measurement of various moving bodies.For large air resistance and friction force which the big moving bodies are subje...Light screen velocity measuring method with unique advantages has been widely used in the velocity measurement of various moving bodies.For large air resistance and friction force which the big moving bodies are subjected to during the light screen velocity measuring,the principle of velocity correction was proposed and a velocity correction equation was derived.A light screen velocity measuring method was used to measure the velocity of big moving bodies which have complex velocity attenuation,and the better results were gained in practical tests.The measuring uncertainty after the velocity correction was calculated.展开更多
Erosive burning is a common burning phenomenon of the gunpowder with inner holes.The actual combustion law of the gunpowder with inner holes can be changed by erosive burning.Pressure difference between the inner and ...Erosive burning is a common burning phenomenon of the gunpowder with inner holes.The actual combustion law of the gunpowder with inner holes can be changed by erosive burning.Pressure difference between the inner and the outer of hole caused by loading density variation of the propellant charge makes erosive burning occur at inner holes during in-bore burning.The effect of erosive burning on burning speed of the propellant is studied by using the effects of flow rate,heat transfer and erosion of the combustion gas in inner holes on burning rate.The mathematic model of erosive burning of the propellant is established.The effects of the factors such as loading density,inner hole size and grain length on erosive burning and interior ballistic performance are analyzed.The method to improve the bore pressure for small charge mass and small firing range by erosive burning is proposed.展开更多
使用隐式大涡模拟方法,研究传统球锥外形、幂次率外形以及冯·卡门外形3种母线形状对整流罩外壁面脉动压力环境的影响。研究结果表明:在跨声速条件下,3种外形都在折角区域产生激波/分离泡干扰现象,从而产生脉动压力的峰值,且峰值位...使用隐式大涡模拟方法,研究传统球锥外形、幂次率外形以及冯·卡门外形3种母线形状对整流罩外壁面脉动压力环境的影响。研究结果表明:在跨声速条件下,3种外形都在折角区域产生激波/分离泡干扰现象,从而产生脉动压力的峰值,且峰值位置与时均激波位置基本一致;幂次率外形与冯·卡门外形能够显著减缓该区域的脉动压力环境,均方根脉动压力的极值比传统球锥外形低17%;由于分离点位置前后移动,使得母线折点与分离点之间的流动速度变化剧烈,同样会引起脉动压力的峰值,而冯·卡门母线在折点处过渡均匀,膨胀加速效应较弱,峰值并不显著。通过瞬时流场涡结构以及声压级频谱分析可知:传统球锥外形在折角之前的锥面区域湍流发展较慢,声压级要低于幂次率与冯卡门外形;分离再附后,传统球锥外形涡结构发展迅速,声压级比其他两种外形高出10 d B左右。展开更多
文摘Light screen velocity measuring method with unique advantages has been widely used in the velocity measurement of various moving bodies.For large air resistance and friction force which the big moving bodies are subjected to during the light screen velocity measuring,the principle of velocity correction was proposed and a velocity correction equation was derived.A light screen velocity measuring method was used to measure the velocity of big moving bodies which have complex velocity attenuation,and the better results were gained in practical tests.The measuring uncertainty after the velocity correction was calculated.
文摘Erosive burning is a common burning phenomenon of the gunpowder with inner holes.The actual combustion law of the gunpowder with inner holes can be changed by erosive burning.Pressure difference between the inner and the outer of hole caused by loading density variation of the propellant charge makes erosive burning occur at inner holes during in-bore burning.The effect of erosive burning on burning speed of the propellant is studied by using the effects of flow rate,heat transfer and erosion of the combustion gas in inner holes on burning rate.The mathematic model of erosive burning of the propellant is established.The effects of the factors such as loading density,inner hole size and grain length on erosive burning and interior ballistic performance are analyzed.The method to improve the bore pressure for small charge mass and small firing range by erosive burning is proposed.
文摘使用隐式大涡模拟方法,研究传统球锥外形、幂次率外形以及冯·卡门外形3种母线形状对整流罩外壁面脉动压力环境的影响。研究结果表明:在跨声速条件下,3种外形都在折角区域产生激波/分离泡干扰现象,从而产生脉动压力的峰值,且峰值位置与时均激波位置基本一致;幂次率外形与冯·卡门外形能够显著减缓该区域的脉动压力环境,均方根脉动压力的极值比传统球锥外形低17%;由于分离点位置前后移动,使得母线折点与分离点之间的流动速度变化剧烈,同样会引起脉动压力的峰值,而冯·卡门母线在折点处过渡均匀,膨胀加速效应较弱,峰值并不显著。通过瞬时流场涡结构以及声压级频谱分析可知:传统球锥外形在折角之前的锥面区域湍流发展较慢,声压级要低于幂次率与冯卡门外形;分离再附后,传统球锥外形涡结构发展迅速,声压级比其他两种外形高出10 d B左右。
