Dust adhesion and deposition behavior in internal cooling duct with pin fins

Abstract

The collision-adhesion and deposition of micron-sized dust particles in the internal cooling duct with pin fin arrays are investigated, integrating the energy dissipation collision model of spherical particles and gas-solid two-phase theory. The effects of particle Stokes number (Stk = 0.12, 0.48, and 3), particle temperature (Tp = 1173, 1223, 1273, and 1343 K), and streamwise pin spacing (S = 2.5, 3, and 3.75D) on the collision ratio, sticking ratio and deposition ratio of particles on pin fins and endwalls are investigated when the inlet Reynold number is 36,575. The results show that the pin collision ratio rises drastically with the increase of particle size, while the sticking ratio decreases. The particle temperature has a minimal impact on the collision ratio, sticking ratio, and deposition ratio when particle temperature is below 1273 K. However, the collision ratio of particles on the pins decreases appreciably when the particle temperature increases further up to 1343 K, while the sticking ratio increases significantly. The pin fin arrays with the streamwise spacing of 3D and 3.75D reduce the number of endwall deposition of particles with Stokes number of 0.12, compared to the pin fin array with a streamwise spacing of 2.5D. The windward region of the pin shows the largest potential for dust deposition and the maximum deposition height occurs at the junction of the pin-endwall. Moreover, the deposits on the pin fin grows and tends to be more uniform with the increase of particle temperature, according to the deposition profile on the pin.