Analysis of Ablation Mechanism of Iron Asteroid Materials Under the Condition of Arc Heater Test

Abstract

When the asteroid enters earth’s atmosphere at a very high speed，the surface temperature rises and the surface material melts and loses under the severe aerodynamic heat. Studying the ablation mechanism of iron asteroids entering the Earth’s atmosphere is of great significance to study the ablation mechanism of iron asteroids entering the Earth’s atmosphere to evaluate the impact of such asteroids on the earth. In 2021，the Hypervelocity Aerodynamics Institute of China Aerodynamics Research and Development Center carried out the ablation test of the spherical cone-shaped iron meteorite model（head radius 20 mm，half cone angle 9 degrees）on the arc heater. The tested simulated state is that the stagnation heat flux is 13.9~19.5 MW/m² and the stagnation pressure is 0.51~0.28 MPa. In this paper，based on the experimental phenomenon，the melting ablation model and the melting layer shear ablation model of iron asteroid material ablation are established. and the ablation test state of meteorite model is calculated by using the coupled solution methodology of aerodynamic heat，ablation and internal heat conduction with moving boundary. The calculation and analysis show that the shear ablation model established in this paper can obtain qualitatively consistent stagnation point ablation rate. If the loss of liquid layer is not considered，the calculated law is contrary to the experiment. The calculation shows that the surface evaporation rate is small compared with the mass loss rate of molten layer，which indicates that the ablation of iron asteroids is dominated by the shear loss of molten layer. It can provide reference for asteroid impact Earth defense.

Keywords

iron asteroid / ablation / melting / shear loss