EXPERIMENTAL-STUDY OF PARTICLE DEPOSITION ONTO A CIRCULAR-CYLINDER IN HIGH-TEMPERATURE PARTICLE-LADEN FLOWS

Abstract

Deposition (transport) of particles onto a cold circular cylindrical surface in high-temperature particle-laden cross flows was investigated experimentally. Local particle deposition efficiencies for two Reynolds numbers (Re = 36, 54) and three wall/gas temperature ratio parameters (T(w)/T(infinity) = 0.731, 0.853, 0.987) were obtained by using scanning electron microscopy (SEM) techniques. Solid TiO2 particles, generated by a fluidized-bed particle generator, ranged in diameter from 0.065 to 20-mu-m. Mainstream particle number density and velocity fields were measured by laser-Doppler anemometry (LDA). Calibration for particle concentration was accomplished with the particle size and number density data obtained from inertial impaction and filtration methods. Thermophoresis and inertial impaction are the important deposition mechanisms for these experimental conditions. The effects of particle size, target temperature ratio parameter, and flow Reynolds number on the particle deposition rates at each local angular position were estimated. The experimental particle deposition rates for small particles are compared to the theoretical thermophoresis correlation.