微乳相变材料的流变及储热性能试验

为提高微乳相变材料的储热性能,制备了石蜡-饱和盐溶液的油包水型微乳相变材料。探究乳化剂种类对液滴直径分布、流变特性及黏温曲线的影响,并重点关注KNO_(3)、NaNO_(3)、NaSO_(4)饱和盐溶液对微乳相变材料热容的影响规律。同时,借助导热仪测定微乳相变材料的热扩散速率,并进一步得到材料的导热系数。此外,为提高微乳相变材料导热性能,对比了添加导热油后的导热性能。结果表明:Span-80作为表面活性剂时,黏度下降较为明显;而Triton(曲拉通)作为表面活性剂时,温度超过75℃黏度才出现下降趋势。值得注意的是,黏度随剪切速率的变化规律归因于材料自身的剪切变稀行为。在40~90℃温度区间内,相变材料的最大热容为182 kJ/kg,是相同条件下水介质的4.3倍。添加导热油可显著提高材料的导热性能,50℃时导热系数由0.233 W/(m·K)提高至0.456 W/(m·K),当温度升至60℃时,这种趋势更加明显。

Rheology of typical emulsifiers and effects on stability of emulsion explosives

Structure of emulsifiers or functionality and molecular weight determines its rheology, emulsification and stability of emulsion explosives. Rheology of typical emulsifiers was studied by automatic rheometer. Relations between rheology and structural properties of typical emulsifiers were analyzed. Experimental results show that viscosity of emulsifiers didn＇ t change with shear rate at room temperature and appeared properties of Newtonian fluid. Viscosity of different component emulsifiers declines with temperature in different modes. The change of strain doesn＇ t affect modu- lus of emulsifiers. Loss modulus increases linearly with the increase of frequency in oscillation and storage modulus does non-linearly. The higher the temperature is, the lower change amplitude of loss modulus with frequency will be. The emulsifiers with imide and amide functionality for emulsion explosives have better shear properties at high temperature and better shapingness and stability at room temperature than other emulsifiers with ester and Sorbin Monoleate （SMO） functionality.

基于AUTODYN的乳化炸药水下爆炸能量分布的数值研究

基于AUTODYN软件建立了水下爆炸一维楔形模型,对空气不耦合装药结构下爆炸能量的输出进行研究。首先获得炸药冲击波压力以及气泡脉动随时间的变化曲线,进一步获知径向不耦合状态下水下爆炸的冲击波峰值压力、气泡最大半径以及脉动周期等数据,并最终得到了不耦合系数下冲击波能以及气泡能的变化情况。将计算结果与已有的水下爆炸实验结果进行了比较分析。结果表明,该计算结果与实验数据吻合较好,证明了利用数值计算手段可以实现定量化表征炸药输出能量随不耦合装药结构的变化规律。

铜基廉价催化剂的火焰合成及甲烷催化特性研究

本文基于预混滞止弱旋火焰系统,以溶于水或乙醇的廉价硝酸盐为前驱物,采用"一步"的雾化火焰方法来合成铜基催化剂纳米颗粒。采用TEM、XRD等分析了合成颗粒的形貌及物相态,进而考察了该催化剂在甲烷催化氧化反应中的催化活性。根据TEM结果,发现乙醇做溶剂时所合成的氧化铜颗粒具有颗粒直径小且结晶度较好的特点。实验结果表明,10 nm氧化铜颗粒体现出良好的甲烷催化性能,但掺杂氧化铝后,铜基催化剂对甲烷的催化性能有所下降,其原因可归结为氧化铝对氧化铜的覆盖作用导致其有效比表面积降低。