浇注 PBX 固化温度场的数值模拟

为了使浇注塑料黏结炸药(PBX)具有均匀的固化温度场,采用COMSOL Multiphysics软件和Fourier数学模型,分别模拟研究了模具尺寸、烘箱与PBX间的温差、PBX固化速率等因素对PBX温度场分布的影响。结果表明:药浆温度低于烘箱温度时,浇注PBX内的温度场呈现由外向里递减的趋势。60 mm×240 mm、100 mm×240 mm、200 mm×240 mm和200 mm×1 000 mm,壁厚都为5 mm的模具,从25℃升至60℃的过程中,模具边缘和中心点的最大温差可分别达到3.22、6.66、10.49℃和13.08℃。200 mm×1 000 mm,壁厚为5 mm的模具分别从0、25、40、50℃升至60℃时,模具边缘和中心点的最大温差可分别达到17.56、13.08、7.02℃和3.36℃。药浆温度与烘箱温度相同时,模具边缘温度最小,中心温度最高,此时影响温度场梯度的主要因素为药浆固化速率的大小。当药浆和烘箱间存在温差,可通过减小模具尺寸、降低浇注PBX内的温度梯度,且浇注PBX的固化尽量采取药浆与烘箱温度一致的固化工艺,此时选择固化速率较小的药浆可实现PBX内的温度基本一致。

Numerical Simulation of Temperature Field of Cast PBX during Curing Process

In order to realize uniform temperature field of the cast plastic bonded explosive (PBX) during curing process, the numerical simulation was conducted by a COMSOL Multiphysics software and a Fourier model. Effects of the size of mold, the temperature difference between the oven and the PBX, PBX curing velocity on the temperature field in PBX were studied. Results show that, when temperature of PBX is lower than that of oven, the temperature field in PBX decreases from the outside to the centre of mold. When the size of mold is respectively 60mm × 240mm、 100mm × 240mm、 200mm × 240mm and 200mm × 1 000mm and mold thickness is 5 mm, in the process of temperature ranging from 25 ℃ to 60 ℃ , the temperature difference between edge point and center point of the mold is respectively 3. 22、6. 66、10. 34 ℃ and 13. 08 ℃ . For 200 mm × 1 000 mm mold with the thickness of 5mm, ranging from 0、25、40 ℃ and 50 ℃to 60 ℃ , the max temperature difference in mold can reach to 17. 56, 13. 08 , 7. 02 ℃ and 3. 36 ℃ respectively. When the temperature of PBX is the same as that of the oven, temperature in the center is the highest, and that in the edge is the lowest. Temperature difference is mainly affected by the curing velocity. When temperature different exists between PBX and oven, the temperature gradient in PBX can be reduced by reducing the dimension of the mould, and low curing velocity can realize temperature field uniform in PBX.