On the calculation method of the view factor for earth to aerostats

Abstract

In order to analyze the effect of the ground-reflected radiation to the skins of the aerostat hull, the calculation method of the view factor for earth to the skins of the aerostat hull is studied. Firstly, the calculation model of the view factor for the area element of the aerostat hull to the ground is established, and the view factor is established as the function of the angle between the area element and the ground. On this basis, the view factor for different shape of aerostats to earth is calculated. To analysis the effect of atmospheric attenuation on the calculation of the view factor, the atmospheric attenuation coefficient is computed according to the available data, and then the view factor of the real condition is calculated. The calculation results show that, without atmospheric attenuation, the view factor for the ground to the spherical aerostat calculated by the traditional method is the same as the method used in this paper. For the ellipsoidal aerostat, the view factor increases with the increases of the fineness ratio, whereas the view factor decreases with the increases of the height.