Speaker
Description
Observation missions of meteoroids entering the Earth’s atmosphere are conducted regularly. Meanwhile a method to replicate the flight in a ground test facilities has been established. Numerical simulations with subsequent comparison of the spectroscopic data, on the other hand, are not yet widely used in this field. This is mainly due to the complex flow environment which not only includes non-equilibrium radiation, but furthermore the outgassing of species from the meteorite.
In this work, simulations of an atmospheric entry of a meteorite with a diameter of 38 mm are performed. A pure iron sphere is assumed and the size and inflow conditions correspond to the ground testing condition. Using the Direct Simulation Monte Carlo method, one trajectory point at an altitude of 80 km is investigated. It is taken into account that iron outgasses on the meteorite’s surface and thus influences the flow field. The outgassing process is simulated as an inflow boundary on the meteorite’s surface, assuming a constant meteorite shape and composition. Since these iron particles do not enter the shock, but are captured and entrained by the flow, there is a large difference in their electronic excitation temperature, the electronic excitation temperature of the freestream, and the electron temperature. However, iron has many radiative transitions that occur in the expected energy range, so accurate predictions of the excitation temperatures for each species are essential. For this purpose, the open source plasma suite PICLas is coupled with a radiation solver and the radiative energy is iteratively coupled back into the flow field. A line-of-sight radiation transport is performed and results are compared to the ground-to-flight extrapolated experimental measurements.
Summary
See content
