Seeding behavior of TiO2 particles in supersonic flows

In this work, the Particle Image Velocimetry (PIV) technique was applied to study the compressible supersonic flow regimes into the Multi-Mach number High-speed (MMH) wind tunnel. To generate sufficient light scattering and flow across shock waves, tracer particles and seeding technique were used, and the scattering and tracking of particles were investigated using the experimental observations and theoretical analysis. It was determined that the actual particle diameter should be around 200nm to grantee an adequate aerodynamic response to velocity gradients in the flow. It was further shown from the PIV measurements over a sharp cone that the uniformity of seeding particles dispersion was very important for the operations of the seeding facility. The present study indicated that PIV technique could be an efficient method for monitoring the flow field of shock wave and subsonic flow regimes.