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
A nonlinear mathematic model taking the nutation and precession angles as variables for the coning motion of projectile was established according to a short period moment projection of the spining projectile. By intro...A nonlinear mathematic model taking the nutation and precession angles as variables for the coning motion of projectile was established according to a short period moment projection of the spining projectile. By introducing the generalized nutation angle and precession angular speed, the model that is difficult to be resolved can be transformed to a resolvable one. The interrelationship between nutation and precession was analyzed based on the linear model, and the stability condition was obtained for the spinning projectile. For the nonlinear model, the effects of the nutation and precession on the limit circle of the projectile's coning motion were investigated, and the analytical relations between the nutation angle and the precession angular speed in the steady coning motion of the spinning projectile were given.展开更多
Traditional intercept probability model has some drawbacks and can not meet the demands of command and control system. Aiming at this problem, a new calculation method based on search theory, terminal control area dis...Traditional intercept probability model has some drawbacks and can not meet the demands of command and control system. Aiming at this problem, a new calculation method based on search theory, terminal control area distribution function of anti-ship missile, target distribution function and missile's radar scan feature is proposed. Under the condition of common target distribution, an intercept probability model for present point attacking is determined. The simulation verifies its effectiveness and establishes the selecting model for aiming point when enemy ships evade in high speed.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
科学的焦炭评价指标有利于焦炭的原料成本控制以及炼焦煤资源的更合理利用,即焦炭在高炉中的性能评价对于冶炼效率、产量和产品质量至关重要。为了解和统计焦炭在高炉中性能评价领域在1994—2023年的研究方向、热点以及研究进展,以中国...科学的焦炭评价指标有利于焦炭的原料成本控制以及炼焦煤资源的更合理利用,即焦炭在高炉中的性能评价对于冶炼效率、产量和产品质量至关重要。为了解和统计焦炭在高炉中性能评价领域在1994—2023年的研究方向、热点以及研究进展,以中国知网(CNKI)和Web of Science(WOS)的相关文章为研究材料,运用文献计量分析法对1994—2023年焦炭在高炉中性能评价领域的论文数量、研究学科、研究机构及作者、关键词、研究内容趋势与前沿热点进行分析。研究通过CiteSpace软件绘制焦炭在高炉中性能评价领域的关键词图谱、关键词时间轴图谱以及关键词突现图谱,并利用office软件对相关数据进行分析。结果表明:焦炭在高炉中性能评价领域国内发文量从1994年开始经历了快速上升、动态平衡、稳步上升3个时期,国外发文量在1994—2009年之间发文量为0,从2010年起经历了爆发式增加、稳步上升2个时期;同时焦炭在高炉中性能评价领域的文章涉及多个研究学科,体现了多学科交叉的特点;焦炭在高炉中性能评价研究领域伴随着环境保护重视程度的加重,国内侧重于关注焦炭热性能、光学组织、炼焦煤、微观结构等方面,国外侧重于焦炭在高炉中的反应行为、CO_(2)捕获等方面。因此加强基础研究、技术创新以及多学科交叉互融的全要素格局对提高焦炭在高炉中性能评价的科学性及其应用具有重要的作用,有助于推动冶金工业朝着更加高效、环保和可持续的方向发展。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.
基金Sponsored by the National Science Foundation of China (10972034)
文摘A nonlinear mathematic model taking the nutation and precession angles as variables for the coning motion of projectile was established according to a short period moment projection of the spining projectile. By introducing the generalized nutation angle and precession angular speed, the model that is difficult to be resolved can be transformed to a resolvable one. The interrelationship between nutation and precession was analyzed based on the linear model, and the stability condition was obtained for the spinning projectile. For the nonlinear model, the effects of the nutation and precession on the limit circle of the projectile's coning motion were investigated, and the analytical relations between the nutation angle and the precession angular speed in the steady coning motion of the spinning projectile were given.
文摘Traditional intercept probability model has some drawbacks and can not meet the demands of command and control system. Aiming at this problem, a new calculation method based on search theory, terminal control area distribution function of anti-ship missile, target distribution function and missile's radar scan feature is proposed. Under the condition of common target distribution, an intercept probability model for present point attacking is determined. The simulation verifies its effectiveness and establishes the selecting model for aiming point when enemy ships evade in high speed.
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.
文摘科学的焦炭评价指标有利于焦炭的原料成本控制以及炼焦煤资源的更合理利用,即焦炭在高炉中的性能评价对于冶炼效率、产量和产品质量至关重要。为了解和统计焦炭在高炉中性能评价领域在1994—2023年的研究方向、热点以及研究进展,以中国知网(CNKI)和Web of Science(WOS)的相关文章为研究材料,运用文献计量分析法对1994—2023年焦炭在高炉中性能评价领域的论文数量、研究学科、研究机构及作者、关键词、研究内容趋势与前沿热点进行分析。研究通过CiteSpace软件绘制焦炭在高炉中性能评价领域的关键词图谱、关键词时间轴图谱以及关键词突现图谱,并利用office软件对相关数据进行分析。结果表明:焦炭在高炉中性能评价领域国内发文量从1994年开始经历了快速上升、动态平衡、稳步上升3个时期,国外发文量在1994—2009年之间发文量为0,从2010年起经历了爆发式增加、稳步上升2个时期;同时焦炭在高炉中性能评价领域的文章涉及多个研究学科,体现了多学科交叉的特点;焦炭在高炉中性能评价研究领域伴随着环境保护重视程度的加重,国内侧重于关注焦炭热性能、光学组织、炼焦煤、微观结构等方面,国外侧重于焦炭在高炉中的反应行为、CO_(2)捕获等方面。因此加强基础研究、技术创新以及多学科交叉互融的全要素格局对提高焦炭在高炉中性能评价的科学性及其应用具有重要的作用,有助于推动冶金工业朝着更加高效、环保和可持续的方向发展。
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。
