Under the different nitrogen-enriched air(NEA) parameters

the inerting process was studied by numerical simulation of a civil airplane center wing tank(CWT). The study show the inerting rule of the CWT under different flow rates and different oxygen concentration. The results show that

when the NEA containing volume fraction of about 95% of the nitrogen and the volume flow rate of the NEA are 0.021

0.028m3/s and 0.042m3/s

the average oxygen volume fraction distribution versus volumetric tank exchange (VTE) are almost the same; when the volume flow rate of the NEA is 0.042 m3/s and the volume fraction of the nitrogen are 92%

94% and 98%

the inerting ratio versus time are the same. It is conclusion that the inerting time of the CWT has nothing to do with the flow rate under the same oxygen concentration

and the flow rate of the NEA determines the inerting ratio of each bay. Based on comparative analysis of the numerical result

it proves that the shrink analogy method can be used to simulate the inerting process of the CWT. The research provides reference for optimizing the design of a transport airplane inerting system.