Ablation of silicate particles in high-speed continuum and transition flow with application to the collection of interplanetary dust particles

摘要

A model for the ablation and deceleration of spheres in continuum and slip flow is presented. Experimentsudwere conducted in which initially spherical 7.1 micron diameter soda-lime glass particles were launched fromudvacuum at ~4500 m s^(-1) through a 0.5 mil (13 micron) plastic film into a capture chamber containing xenonudat 0.1 and 0.2 atm and 295 K. Samples of ablated particles were collected and inspected using scanning electronudmicroscopy (SEM). It was found that the ratio of the ablated particle radius (R_f) to the initial radius (R_0)uddepends on the gas pressure such that at 0.1 atm, R_f/R_0 = 0.67 ± 0.08, and at 0.2 atm, R_f/R_0 = 0.88 ± 0.08.udThe model agrees with these results if the heat of ablation Q is set to 1.5 ± 0.2 MJ kg^(-1). This value of Qudapproximately corresponds to the energy needed to raise the particle temperature from 295 to 1300 K, theudworking point of soda-lime glass. This indicates that the mechanism of ablation is melting and blowing ofudmaterial from the particle's surface.