航空燃油类型对催化惰化系统性能的影响

在设计了一种催化惰化系统流程并描述其工作原理的基础上,以从油箱中抽吸气体的摩尔流量为基准,推导了流经催化反应器后各气体组分的流量关系,通过质量守恒方程及气体平衡溶解关系,建立了油箱气相空间气体浓度变化的数学模型。选择了RP-3、RP-5和RP-6燃油作为对象,用所建立的数学模型计算了不同载油率和催化反应器效率下的气相空间氧浓度变化关系。研究显示,由于3种燃油的蒸汽压不同,造成从外界环境补气及进入油箱的混合惰气流量不同,从而导致气相空间氧浓度的变化规律差异远大于采用中空纤维膜的机载惰化系统。因此,在设计催化惰化系统时要充分考虑燃油类型对惰化系统性能的影响。

Performance of catalytic inerting system affected by various aviation jet fuels

A novel catalytic inerting system is designed and its working principle is described in detail. The outflow rates of each gas component passing through the catalytic reactor are derived in which the molar flow rate of suction gas is used as a baseline. A mathematical model to calculate the concentrations of all gas components on ullage of the fuel tank is set up via the mass conservation equations. Three different aviation jet fuels including RP-3, RP-5 and RP-6 are chosen to calculate the variation of the oxygen concentration on ullage under various fuel loads and efficiencies of the catalytic reactor via the given mathematical model. The study reveals that owning to the disparate vapor pressure of the chosen aviation jet fuels, the flow rates of the supplemental air from the atmospheric environment and the produced mixed inerting gas entering into the fuel tank are extremely different. Hence, the difference of the variation of the oxygen concentration on ullage adopting these there jet fuels in the catalytic inerting system is larger than that in the hollow fiber membrane based on-board inert gas generation system. It is suggested that the influence of the type of aviation jet fuels should be considered carefully during the design of a catalytic inerting system.