爆轰管内氢氧爆炸过程与碳-铁纳米材料生长研究

Study on hydrogen-oxygen detonation process and the growth of carbon-iron nanomaterials in a detonation tube

为研究气相爆轰合成碳-铁纳米材料的爆炸过程,采用氢氧爆炸试验与数值模拟相结合的方式研究了不同氢氧摩尔比(2∶1、3∶1和4∶1)对爆轰参数(爆速、爆温、爆压)峰值时程曲线与碳-铁纳米材料形貌的影响。研究表明:爆轰管内氢氧爆炸包括爆轰波的传播与燃烧波的衰减2个过程,且氢氧摩尔比对爆速、爆温、爆压的峰值时程曲线影响十分显著。随着氢氧摩尔比的提高,爆轰波的爆速、爆温、爆压及其衰减速率均呈减小趋势。氢氧摩尔比通过影响爆轰波的传播与衰减而作用于碳-铁纳米材料形貌的生长。零氧平衡时,样品为碳包铁纳米颗粒,随着氢氧摩尔比的提高,样品中碳纳米管的数量逐渐增多。调整氢氧摩尔比可实现对爆轰波传播与衰减过程的控制,达到气相爆轰控制性制备特定形貌的碳-铁纳米材料的目的。

To study the explosion process of carbon-iron nanomaterials synthesized by gaseous detonation,the effects of different molar ratios of hydrogen to oxygen(2∶1,3∶1,4∶1)on the peak value time-history curve of detonation parameters(detonation velocity,detonation temperature,and detonation pressure)and the morphology of carbon-iron nanomaterials were studied by combination of hydrogen-oxygen experiments and numerical simulations.The explosion experiments used hydrogen and oxygen with a purity of 99.999%in a closed detonation tube.The precursor was ferrocene with a purity of 99%.A high-speed camera was used to observe in the middle of the tube.After the experiments,the samples were collected and characterized by transmission electron microscopy.The numerical simulation used ICEM software for modeling and meshing and then used Fluent software to verify the rationality of the mesh size,and then performed simulation calculations after confirming the optimal mesh size.The results indicate that hydrogen-oxygen explosion inside a detonation tube involves two processes:the propagation of detonation waves and the attenuation of combustion waves,and the hydrogen-oxygen molar ratio has a significant impact on the peak time history curves of detonation velocity,detonation temperature,and detonation pressure.With the increase of the molar ratio of hydrogen to oxygen,the detonation velocity,detonation temperature,detonation pressure,and attenuation rate of the detonation wave all decrease.The molar ratio of hydrogen to oxygen affects the morphology growth of carbon-iron nanomaterials by influencing the propagation and attenuation of detonation waves.At zero oxygen balance,the sample consists of carbon-coated iron nanoparticles.As the hydrogen-oxygen molar ratio increases,the number of carbon nanotubes in the sample gradually increases.Adjusting the molar ratio of hydrogen to oxygen can achieve control over the propagation and attenuation process of detonation waves,and also achieve the goal of controlling the preparation of carbon iron nanomaterials with specific morphologies through gaseous detonation.