C/H/O/N/B体系气相燃烧化学动力学模型及计算研究

Research on Model and Calculation of Chemical Kinetics Model of C/H/O/N/B System

关键词:  固体推进剂  化学动力学  燃烧模型  气相 

Key words:  Solid propellant  Chemical kinetics  Combustion model  Gas-phase

摘要:

为了更加深入地研究硼粒子的点火和燃烧机理,在Pasternkck和Zhou的模型的基础上,通过补充基元反应和修正基元反应的动力学参数,建立起了新的C/H/O/N/B体系气相燃烧动力学模型,该模型包含31种组分,190个正反基元反应。采用新的模型对贫氧体系气相燃烧过程进行计算,并改变体系的初始温度及压强,研究其对平衡温度和硼的氧化物平衡摩尔分数的影响。计算结果表明:(1)体系平衡后硼元素主要以硼的氧化物形式存在,其中BO和BO₂的摩尔分数随反应时间的增加先升高后降低,B₂O₃的摩尔分数随着反应时间的增加而不断升高。(2)提高初始温度和压强不但能使体系的平衡温度提高,而且能缩短体系达到平衡的时间。(3)提高初始温度会使B₂O₃更多地解离为BO和BO₂,不利于硼燃料能量的完全释放,但提高压强会抵制B₂O₃的解离,从而会在一定程度上提高硼燃料的能量释放。 

Abstract:

In order to study the ignition and combustion mechanism of boron particle more deeply, a homogenous gas-phase combustion model of C/H/O/N/B system was established based on the model of Pasternkck and Zhou. Some simple reactions were added to the model and some thermodynamic data was revised, and there were 31gas-phase species and 190forward-reverse simple reactions in the model. The gas-phase combustion was calculated for one kind of fuel-rich system by using the new model and the effects of initial temperature and pressure on the temperature of the system and equilibrium mole fraction of boron oxide were studied. The calculation results show that:(1) Boron oxide is the mainly products among all the boride products when the system reaches equilibrium state. Mole fraction of BO and BO_2increases firstly and then decreases, while mole fraction of B₂O_3increases with the reaction time. (2) Increasing the initial temperature and pressure can increase the equilibrium temperature of the system and decrease the equilibrium time. (3) More B₂O_3is dissociated to be BO and BO_2when the initial temperature increases which will do harm for the heat release of the fuel containing boron, while the higher pressure is benefit for the heat release of the fuel containing boron by inhibiting the dissociation of B₂O₃. 