某飞机多舱燃油箱洗涤惰化的工程计算

为研究某飞机多舱燃油箱洗涤惰化过程,将洗涤气分为与燃油发生传质部分和未发生传质部分,通过理论计算获得洗涤气与燃油发生传质并向气相空间逸出的氧气量.未发生传质的部分用于气相冲洗,其余与液相洗涤逸出量相结合,建立模型进行工程计算.由此将整个洗涤惰化过程转化为有逸出的气相冲洗过程.结果表明:这种将洗涤惰化转化为有逸出的冲洗模型是可行的,其结果与实验值基本吻合.随着时间的增长,气相氧体积分数一般经历先增长后下降的过程,最终趋向于洗涤气体积分数.多舱飞机燃油箱的各舱氧体积分数值变化快慢与进气出气口位置和各舱体积有关.

Scrubbing inerting engineering calculations in multi-bay fuel tank of an aircraft

In order to research the scrubbing inerting process in multi-bay fuel tank of an aircraft, scrubbing gas was transformed into two sections, fuel mass transfer section and no-mass transfer section. By theoretical calculation, fuel was in mass transfer with scrubbing gas and the amount of oxygen escaped to the gas phase space was obtained. The no-mass transfer section could be used to access the gas space directly considered as fuel washing process. The other section could be combined to build the model for engineering calculations by working out the amount of oxygen spilling from fuel. In this way,the whole scrubbing inerting process was transformed into washing process with escaping gas. The results show that the model for the conversion of scrubbing inerting to washing with overflow is really credible. The results of the model are consistent with experiment results. As time increases, the gas phase oxygen volume fraction will increase and then decrease again, converging to a final gas phase oxygen volume fraction equal to the value of the scrubbed gas. The result of multi-bay fuel scrubbing shows the time required for stabilizing is related to the distance from the inlet and the volume of each bay.