IMPACT OF HELIUM PERMEABILITY ON ENDURANCE AND ALTITUDE CONTROL OF GEOSTATIONARY STRATOSPHERIC AIRSHIP - A MATHEMATICAL MODEL

摘要

A geostationary stratospheric airship is lighter than air platform to be used for several civil and military purposes. In this study, the impact of Helium permeation through the hull and ballonet skin is considered. Mathematical modeling of the system is being done to estimate the amount of Helium and air transmission through the hull and the ballonet skin for a general airship system. Impact of permeation mainly affecting its ability to maintain constant altitude and a minimum level of differential pressure is shown in this study. A method is also devised so as to develop an open loop control system to maintain the altitude of the airship by maintaining the net vertical force due to buoyancy and weight on the airship as zero. Both the cases with and without the altitude control are simulated by numerically solving the model using RK4 algorithm. The results obtained are discussed and appropriate conclusions are drawn from the analysis.