Modeling and simulation of a stratospheric airship based on triple-gasbag principle

A stratospheric airship is difficult to achieve long duration flight at about 20km altitude at mid or low latitudes, where it endures pressure changes due to the heating and cooling of the day-night cycle. In order to overcome these difficulties, this paper proposed a novel stratospheric airship based on triple-gasbag principle, and investigated its static and dynamic behavior. Firstly, this paper briefly described the concept design of a triple-gasbag airship. Then, to investigate the dynamic flight performance of this airship, the paper built a vertical flight dynamics model coupled with distributed parameter thermal model and gas thermodynamic model. Moreover, the distributed thermal model was verified by comparing the simulation results with the flight experimental data. The comparison results show that the deviation between simulation and experimental data is less than 2.4%. Finally, to verify the effect of triple-gasbag principle on reducing differential pressure, this paper investigated the transient behavior of the thermodynamic and kinetic parameters of the triple-gasbag airship at floating conditions using the ammonia phase change combined with air exchange method. The simulation results indicate that if the volume of ammonia gasbag is 10% of the overall volume of the airship, the triple-gasbag method can reduce the differential pressure over 45%. In summary, the triple-gasbag principle is effective in regulating the pressure and altitude respectively, and can greatly reduce super pressure oscillation of the airship during diurnal cycle.