Nanoparticle dispersion and coagulation in a turbulent round jet

► The nanoparticle two-phase flow was generated by the spray drying method. ► The particle size distribution was measured by a scanning mobility particle sizer. ► The particle diameters increased in the radial and axial directions. ► The increase was attributed to the coagulation effect induced by the turbulence. ► The particle number density decreased with the ambient air entrainment.