Simulation and analysis of thermal characteristics of stratoshperic airship

To estimate spatial distribution of thermal characteristics of stratospheric airships, this paper considers the complex thermodynamic environment in which the airships operate, and establishes a computational model for the thermal characteristics of the airships, including thermal equilibrium equations, direct solar radiation, scattered solar radiation, Earth-reflected radiation, atmospheric infrared radiation, Earth infrared radiation, radiation heat transfer and convective heat transfer between skin units. With this model, theoretical simulations of temperature fields were performed for the airships. The simulation results show that the skin temperature of stratospheric airships are mainly affected by the intensity of solar radiation, which is lower at night and higher during the day. Under floating conditions, the skin temperature field exhibits high non-uniformity and significant temporal variations. The skin solar absorptivity of the stratospheric airship has a significant effect on the skin temperature, as reducing the solar absorptivity from 0.5 to 0.2 decreases the maximum skin temperature from 322.94K to 263.98K, with a decrease of 58.96K. The skin surface infrared emissivity is another factor which has a significant effect on the skin temperature, as increasing the surface infrared emissivity from 0.5 to 0.8 reduces the maximum skin temperature from 297.35K to 274.74K, with a decrease of 22.61K. Different seasons have a certain influence on the skin surface temperature of stratospheric airships, with a temperature difference of about 15K between the summer and the winter solstices, mainly due to the difference in solar radiation intensity received by the skin of the airship, which affects the temperature variation of the skin. The theoretical model established in this paper provide a useful tool for multi-physics simulations and analyses of stratospheric airships.