We applied an indirect photoelectric charging technique to develop a new aerosol charger. The charger consists of two coaxial tubes, the inner UV lamp wrapped with stainless mesh and the outer Al cylinder. In this system, the effects of flow rate, particle size, and electric field was examined to search the optimal charging conditions with experimental and numerical methods. According to results, the average number of elementary charge on particles increases from 2.5 to 5.5 as particle size increases from 50nm to 130nm at 2.5 lpm and 100V. The average number of elementary charge on particles was maximized at 25V as the electric potential between the stainless mesh and Al plate was varied from 0V to 400V.
