Aerosol particle size growth by simultaneous coagulation and condensation with diffusion losses in laminar flow tubes

Abstract

The growth process of evaporation–condensation aerosol particles by simultaneous Brownian coagulation and condensation in a laminar flow tube downstream the particle generation unit has been studied. Size growth has been modeled assuming that vapor concentration in the tube just after the generator is already very low (negligible self-nucleation). The model, which also accounts for particle diffusion losses, permits an easy estimation of the coagulation and condensation rates. The effect of the generator cooling temperature on the relative importance of coagulation and condensation in the after-generation particle growth process has been examined. Experiments have shown that aerosols generated by traditional evaporation–condensation methods still grow by condensation much after they have left the generator.