Particle precipitation in duct flow is important in particle industry and HAVC. There are various duct geometries in industry

but most experiments in the literatures were conducted on smooth ducts. In the present study

a rectangular duct with a series of staggered baffles being installing inside was set up. Power plant ash and CaCO3 particles were sprayed into the air flow through the duct. The measurement showed that the baffles significantly increased the particle precipitation by orders of magnitude

which was consistent with the modeling results in the literatures. By greasing the baffle surfaces

the reflection of particles on the surfaces were repressed and thus precipitation was enhanced by a limited amount. The results showed that the baffle structures have critical influence on the fine particle deposition while the baffle surface property may not be a significant factor.