气体分配方式对民机多隔仓燃油箱惰化的影响

在假设燃油箱整体和各隔仓无质量堆积的前提下,建立了一种可根据压力差自动确定流动方向和流量的数学模型,并给出了迭代法计算的步骤,然后采用微元法获得了惰化过程中各隔仓体积氧浓度随换气次数的关系.以波音747中央翼油箱为对象,与国外文献中公布的实验数据进行了对比,验证了所建模型有较高的计算精度.以国产某型客机中央翼燃油箱为研究对象,给出了4种不同的富氮气体进气孔设置及2种气体分配方式,比较了它们对惰化过程的影响,结果显示,将富氮气体按体积平均方式通入所有的隔仓具有最好的惰化效果,而将进气孔口设置在外侧隔仓并单独进气的惰化效果最差,而且在中部对称位置的隔仓上设置进气孔优于非对称位置设置进气孔.

Influent of inerting process of multi-bays central fuel tank for civil passenger airplane under various gas distributions

Based on the assumption of zero mass accumulation in the fuel tank and all bays,a mathematical model to automatically determine the flow direction and rate via the pressure difference was set up,and iterative steps were offered.Then,the mole concentration of the oxygen in the each bay related to volumetric tank exchange of ullage via the differential method was obtained.Adopting Boeing 747 central wing tank as the object of study,the calculating results of the models show highly accurate with the experimental data published on the foreign literature.The central fuel tank of an unnamed domestic passenger airplane was employed to study the inerting process influenced by 4 different configurations of the nitrogen-enriched air inlet port and 2 different gas distributions.The result reveals that the inering effect is the best to distribute the nitrogen-enriched air into all bays according to the volume average while it is the worst to solo distribute the nitrogen-enriched air into an outside bay.Moreover,it is better to emplace the inlet ports on the symmetrical bays than the asymmetrical bays.