激励条件下燃油箱多组分气液非平衡传质机理及可燃特性研究

The jet fuel vapor on ullage of the aircraft fuel tank is oxidized into carbon dioxide and water under its autoignition temperature via a catalytic combustor in the oxygen consumed catalytic Inerting technology. The mixed carbon dioxide and nitrogen which does not participate in the reaction process is injected into ullage of the fuel tank to aim the purpose of fire and explosion protections. It is one of the latest technologies of the on-board inert gas generation system and is paid attractively attentions owning to its compact size and high efficiency. A complicated gas-liquid system, composed of CO2, N2, O2, hydrocarbon vapour and liquid jet fuel, is formed. Under the action of the internal and external heat sources, and excitations the components and concentrations on ullage vary owning to the complicated mass transfer process of the dissolution/evolution of gases, and the evaporation/condensation of the jet fuel, so the inlet boundary of the catalytic reactor and the flammability of the fuel tank are dramatically affected. In the present study, the domestic RP-3 jet fuel is designated as the research object, the flammability limits and limiting oxygen concentration (LOC) are experimentally tested under various initial pressures, temperatures and ignitions energies. Four types of excitations including heat, pressure, fuel pump and harmonic movement are employed to visually investigate the phenomena of fluctuation, entrainment and breakage on the gas-liquid surface. A novel multi-dimensional laser holographic interferometric method is developed to measure the distributions of gas concentration in the fuel. A transient coupled heat and mass transfer model of the fuel tank, in which the mass transfer at gas-liquid interface is described by the vortex diffusion theory, is setup to predict the variation of gas components via the consideration of the surface tension and marangoni effect. The study could provide a theoretical foundation for the application of this kind of inerting technologies, the revision of the MOC index listed in AC 25.981, and the assessment of the flammability of the fuel tank of civil aircrafts.

耗氧催化惰化技术在自燃温度下将燃油蒸汽氧化为CO2和水，CO2与未反应的N2混合后对油箱惰化，达到防火抑爆目的，其结构紧凑效率高，是最新机载惰化方式。油箱中会形成CO2、N2、O2、碳氢物蒸汽和燃油组成的复杂气液体系，在内外热源和激励作用下，气体溶解逸出及燃油蒸发冷凝等复杂传质行为会造成气相空间组成变化，影响反应器入口边界和油箱可燃性。以国产RP-3燃油为对象，在不同温度、压力和点火能量下测定燃油在混合惰气中的燃爆极限和极限氧浓度；引入热、压力、油泵和简谐振动四种激励方式，采用可视化方法观测液面波动、卷吸和破碎，设计一种多维度激光干涉法测量燃油中的浓度场；考虑界面的表面张力和Marangoni效应，采用旋涡扩散理论描述气液相际界面传质，建立油箱瞬态传热传质耦合模型，预测油箱中气体组分的变化。研究可为此类惰化技术在民机25.981适航条款中惰性化指标修订和可燃性评估方法提供基础理论依据。

耗氧催化惰化技术在自燃温度下将燃油蒸汽氧化为CO2和水，CO2与未反应的N2混合后对油箱惰化，达到防火抑爆目的，其结构紧凑效率高，是最新机载惰化方式。油箱中会形成CO2、N2、O2、碳氢物蒸汽和燃油组成的复杂气液体系，在内外热源和激励作用下，气体溶解逸出及燃油蒸发冷凝等复杂传质行为会造成气相空间组成变化，影响反应器入口边界和油箱可燃性。以国产RP-3燃油为对象，在不同温度、压力和点火能量下测定燃油在混合惰气中的燃爆极限和极限氧浓度；引入热、压力、油泵和简谐振动四种激励方式，采用可视化方法观测液面波动、卷吸和破碎，设计一种多维度激光干涉法测量燃油中的浓度场；考虑界面的表面张力和Marangoni效应，采用旋涡扩散理论描述气液相际界面传质，建立油箱瞬态传热传质耦合模型，预测油箱中气体组分的变化。研究可为此类惰化技术在民机25.981适航条款中惰性化指标修订和可燃性评估方法提供基础理论依据。