THERMAL MODEL OF AN AIRSHIP WITH SOLAR ARRAYS AND A BALLONET

D. Greenhalgh, A. R. Tatnall

Abstract: Airships and other lighter than air vehicles depend on a lifting gas to provide buoyancy. This lifting gas is subject to changes in temperature due to external heating which can affect its pressure and volume. Many airship designs contain ballonet systems to allow the lifting gas to maintain a set pressure despite changes in temperature. This study improves the accuracy of airship thermal models by incorporating the effects of a ballonet system. A transient thermal model based on a finite element discretisation for the structure and lumped averages for the gases was developed to account for the effects of a ballonet system by formulating the first law of thermodynamics in conjunction with an ideal gas representation of the lifting gas and ballonet air. Solutions to the resulting differential equation were found via the implicit Euler method using a Newton-Krylov solver. The results of the simulation were compared to previously published experimental results of an airship with a solar array and ballonet systems. The simulation results show a good agreement with the experimental results (r = 0.9). As such, this model can be used to aid in the design of future airships and aerostats with ballonet structures.

Keywords: Airship, Aerostat, Thermal Analysis, Balloonet

DOI: https://doi.org/10.15623/ijret.2014.0329013