Thermal performance analysis and comparison of stratospheric airships with rotatable and fixed photovoltaic array

Abstract

The thermal performance of stratospheric airship is closely related to the superheat/overpressure of airship, the thermal stress of the hull, the mechanics property of the envelope, as well as the airship reliability and lifetime. A comprehensive understanding of the thermal performance of the airship is important for the increase of airship applications. For the improved airship with rotatable photovoltaic array, the location of the photovoltaic array changes with time to utilize the solar radiation maximally, which decrease the mass of photovoltaic array greatly. The thermal performance may be different with the traditional airship with fixed photovoltaic array. In this paper, a thermal model of stratospheric airship with rotatable photovoltaic array was proposed to investigate the thermal performance and compare with traditional stratospheric airship with fixed photovoltaic array. A user define function program in computational fluid dynamic software was developed based on the model. The temperature distribution of surface and flow field of inner lifting gas of the airship with rotatable/fixed photovoltaic array were simulated and compared. The result shows that the temperatures of photovoltaic array and envelope of the improved airship are slight higher than that of traditional airship. The temperature fields of the Helium are also various and the uneven temperature distribution leads to the formation of eddies and chaotic state of the flow field. It is helpful in guiding the design of novel stratospheric airship with low-weight power system, especially the design of thermal control system and inner pressure regulation system of the airship.