A numerical algorithm is used to study the 'fan-spreading' mechanism of axial particle turbulence acquisition and the effects on it of the inlet particle diameter distribution, downstream of a particle-laden, turbulent, round jet. The algorithm is based on the particle-source-in-cell numerical technique for two-phase flows. Eulerian equations are used for the description of the gas-phase dynamics, whilst the solid particles are treated within the Lagrangian framework. The turbulent particle dispersion is simulated with the aid of the stochastic separated flow model. It was found that the 'fan-spreading' turbulence is very much affected by the mean and standard deviation of the particle size distribution; in particular, it was found that the 'fanspreading' mechanism becomes weaker when the standard deviation of the particle diameter distribution is higher and the mean particle diameter smaller. An analytical expression describing the axial particle turbulence due to 'fan-spreading' is proposed and tested, along with a similarity profile valid for the particles of bigger size. KFY WORDS 'Fan-spreading' Particle turbulence Two-phase flow Turbulent jet Particle-laden jet Numerical study