Analysis of Multivane Radiometer Arrays in High-Altitude Propulsion

摘要

A near-space propulsion system using radiometric forces is notionally developed for a generic near-space vehicle. The purpose of the propulsion system is to provide wind-disturbance compensation for the vehicle operating at an altitude range of 40 to 80 km. An experimental analysis is performed in order to determine the performance of a single radiometer vane, as well as how a single vane is influenced by neighboring vanes in an array. A numerical analysis is also performed to verify the experimental trends and give further insight into radiometric flows. All design and performance parameters for a notional system are extrapolated from the experimental results. The proposed design is an integrated system in which an array of radiometers lines the surface of the vehicle and operates on solar power. Each vane consists of an Aerogel thermal barrier with one of the faces coated to absorb solar energy. For a system operating at 60 km, each individual vane has a height of 1.5 mm a thickness of approximately 640 /um in order to generate a temperature difference of 20 K across the vane. The vanes are set a distance of 1.5 mm apart in order to maximize the total thrust per array area per system mass. In the 60 km case, the propulsion system produces 15.6 mN/m~2 of thrust per unit array area with an areal density of 12.5 g/m~2. Results for varying altitudes from 40 to 80 km are also presented.