The particle dispersion characteristics of the dense gas-solids two-phase coaxial jets were investigated with high-speed camera.The results showed that with increasing gas velocity,three particle dispersion modes were observed:shear dispersion,wave dispersion and oscillating dispersion,after the particle flow passed through the intact length.The normalized intact length decreased with increasing gas velocity.For the wave dispersion,the unstable wavelength increased linearly with axial distance at different gas velocities.For the oscillating dispersion,oscillating frequency decreased at first and then increased with increasing gas velocity,so the oscillating frequency had a minimum when the gas velocity was about 65 m·s-1.
