【摘要】 针对在等离子体点火过程中,当热量传播速度为有限值时,其传热机理和适用经典傅里叶定律时热量传播速度为无限大时完全不同。通过对傅里叶定律进行修改,使其能够在强瞬态导热中应用。在柱坐标下建立火药颗粒强瞬态热传导的轴对称二维数学物理模型,并进行数值模拟,计算得到了火药颗粒内部温度场分布,分析了不同因素对等离子体点火性能特别是点火延迟的影响以及火药颗粒内部加入热电偶后对内部温度场分布的影响。计算结果表明:等离子体辐射温度越高,点火延迟越小;辐射吸收层越小,表面温度达到着火点所需时间越短,点火延迟也就越小;松驰时间对等离子体点火产生滞后影响,松驰时间大使热传导系统保持原有稳定状态的能力就强,热传导能量难以向内部渗透。当插入热电偶测量温度时,热电偶对温度场分布会产生影响。更多还原

【Abstract】 Instantaneous heat conduction analysis in powder grains was discussed.When the heat spread speed is a finite value in the process of plasma ignition,the theory of heat conduction is quite different from the classical Fourier law applied to the process when the heat spread speed is infinite.The classical Fourier law is modified when applied to the instantaneous heat conduction.A two-dimensional instantaneous heat conduction model of the powder grain plasma ignition process was established under cylindrical coordinate,using the finite difference equation and the numerical simulation to calculate the distribution of the temperature field in powder grains.In the process of the plasma ignition,different factors are considered to analyze the influences on the ignition delay,and the distribution of the temperature field is also analyzed when a thermocouple is inserted in powder grains.The numerical results show that: 1) along with the increase of plasma temperature,the ignition of energetic materials is shortened;2) the thickness of the plasma radiation absorption decreases,the ignition delay is small;3) when the heat relaxation time decreases,the temperature field is further influenced;4) when the thermocouple is inserted to measure the temperature,the temperature is influenced.更多还原