Improved Thermal and Vertical Trajectory Model for Performance Prediction of Stratospheric Balloons.

Prediction of thermal behavior and trajectory plays an important role in design and operation of stratospheric balloons. First, a more rounded and improved thermal and vertical trajectory model for performance prediction of stratospheric super-pressure balloons is established, including thermal models for solar radiation, infrared radiation, heat convection, and vertical dynamic model. Meanwhile, mathematical models for gas expulsion and ballast drop are also established. The new model is suitable for both the ascent stage and floating condition of stratospheric super-pressure balloon. Then, a computer program is developed based on the improved model, and predicting accuracy of the model is verified using experimental results of a stratospheric balloon. In the end, performance parameters of a new concept stratospheric balloon in ascent stage and floating condition are obtained, including film temperature, helium gas temperature, pressure differential, altitude, and velocity. Simulation results show that stratospheric balloons experience supercooling and superheating in the ascent stage and floating condition respectively, and both helium gas temperature and difference pressure have great change from day to night in the floating condition. [ABSTRACT FROM AUTHOR]