Fragment tracking for microparticle breakage resulting from high-speed impacts

Abstract

Particle breakage is of great interest within multiple engineering disciplines, as applications exist in powder production, industrial pipe flow, and aircraft engines. While important, not many measurement techniques exist to directly measure particle breakage. This work introduces an image-based measurement technique and algorithm that detects breakage and tracks resulting fragments for high-speed particles. This allows for the breakage probability (or selection function) to be measured directly by comparing the number of particles that bounce to the number of particles that break for a given impact condition. The presented algorithm is also shown to have an uncertainty of no more than $\pm 6\%$. Moreover, resulting fragment velocities and angles are related to initial impact conditions and compared with corresponding particle bounce results. The breakage algorithm is demonstrated on experimental data consisting of $150\mathrm{\mu m}-250\mathrm{\mu m}$ sieved quartz incident on Grade 4 (commercially pure) titanium with speeds between $60m/s$ and $100m/s$ and a nominal angle of incidence of ${30}^{°}$. It is demonstrated that the technique yields good results as groups of fragments resulting from particle breakage are shown to have the same average rebounding angle and a lower average rebounding velocity compared to particles that bounce. These findings underscore the improved particle breakage measurements that this new technique achieves.