Abstract: The stability of particle uniform distribution in concurrent-up gas-solid flow is analyzed in this paper.The equations of small disturbances departing from the uniformity are derived on the basis of the particle kinetic theory.The stability ranges of the system on the parameters space of disturbance wavelength and the particle volume fraction are presented.It is found that the system is stable for the disturbances with very short wavelength and unstable for disturbances with longer wavelength unless the particle phase is very dense.The situation of particle uniform distribution can hardly be stable for all disturbances in the case of higher superficial gas velocity.When the particle phase is very dilute,only the disturbances with very long wavelength can drive the system unstable,the distribution of particles can remain uniformity to some extent.As the particle diameter increases,the range of particle concentration in which particle can distribute uniformly becomes narrower when the particle diameter is less than a critical value,while it will become wider when the particle diameter is larger.The particles with small density can distribute uniformly in a wider range of particle concentration.

Key words: stability analysis, gas-solid flows, particle kinetic theory, particle distribution