不同类型惰气对飞机燃油箱可燃性影响理论研究

以低温可控耗氧型催化惰化技术为背景,采用微元计算法,建立了使用混合惰气的油箱气相空间平衡氧浓度数学模型。在考虑燃油温度、载油率、气体组分等因素的情况下,通过模型计算了平衡氧浓度随高度的变化关系,同时与使用富氮气体的油箱进行了对比。研究结果表明:在地面采用混合惰气惰化油箱后,平衡氧浓度随着飞行高度增加而降低,而采用富氮气体惰化的油箱则完全相反。油箱载油率越大,气相空间氧浓度变化幅度越大。燃油温度增加,对采用混合惰气的油箱不利,但是对采用富氮气体的油箱有利。总体而言,使用混合惰气惰化油箱可有效抑制油箱气相空间可燃性随飞行高度而增加的不利趋势,该研究结果可为混合惰气地面惰化和预洗涤技术提供理论基础。

Theoretical Study on Flammability of Aircraft Fuel Tank Affected by Various Inert Gases

Based on low temperature controlled oxygen consumption catalytic inerting technology, a mathematic model of the equilibrium oxygen concentration of the fuel tank ullage with mixed inert gas is established using the method of differential element calculation. The relationship between equilibrium oxygen concentration and height is calculated by the model with the consideration of fuel temperature, fuel load and gas component and compared with fuel tank using nitrogen enriched air. The results show that when mixed inert gas is used to inert the fuel tank on the ground, the equilibrium oxygen concentration decreases with the increase of flight height, while it is completely the opposite when the nitrogen enriched air is used. The higher the fuel load is, the greater the variation range of oxygen concentration in the ullage. The increase in fuel temperature is bad for fuel tank with mixed inert gas, but good for those with nitrogen enriched air. In general, the use of mixed inert gas to inert fuel tank can effectively suppress the adverse trend of the fuel tank flammability increasing with flight height, and the study results can provide theoretical basis for ground inerting and fuel pre-scrubbing technology using mixed inert gas.