Three dimensional simulation of stratospheric airship ice accretion in ascending process

摘要

A three dimensional ice accretion model was proposed to simulate the icing performance of a stratospheric airship in ascending process. The ice accretion model consists of three modules, a) thermal and airflow module with the thermal environment and heat transfer mechanism of the airship incorporated, b) droplet impingement module that is based on Eulerian two phase flow theory and c) ice accretion module that is based on the heat and mass conservation analysis of the control volume. The sets of equations describing and a roadmap of validating the aforementioned modules are presented. Then, the influence of the thermal environment on the thermal performance of the airship were analyzed numerically, and a further inspection into the icing performance of a stratospheric airship was conducted. The results shown that when the solar radiation was attenuated by clouds to a certain extent, the temperature of the airship may below the icing point, thus arise the risk of ice accretion on the airship surface. The ice would accreted on the windward surface of the airship and will on one hand deteriorate the aerodynamic performance, and on the other hand break the lift and gravity balance of the airship, which would seriously deteriorate the flight performance of the airship.