抄録
This paper investigates the axial flow range where the particle velocities are maximized, and where kinetic energy of spray powder is maximized in high-velocity oxy-fuel (HVOF) thermal spray process, regardless of the particle diameter and material density of the particle. The ranges of diameter and material density of the spray particles selected in this paper are 10-60μm and 6000-16000 kg/m3. The gas/particle velocities are calculated by using one-dimensional simulation, with the equivalence ratio of the HVOF thermal spray gun to be 0.5, 1.0 and 1.5. It was assumed that a single particle travels along the centerline of the gun and jet-flow outside the gun. The present research reveals that 1) The particle velocities are maximized within the flow direction range of x = 108-113mm, 2) The kinetic energy of particles is maximized within the range of x = 121- 154mm for three different particle-diameter distributions, 3) The aforementioned results 1) and 2) are valid for the Stokes number, St, in the range of approximately 7 < St < 100.
