抄録
Effects of internal geometry and operating conditions on the aerosol flow pattern in a differential mobility analyzer (DMA) were numerically investigated. The internal three-dimensional structure of a Cluster-DMA (Okuyama et al., J. Aerosol Res., Jpn., 13, 83 (1998)) was employed to simulate the complex flow patterns in the DMA, including the swirling flow that develops near the aerosol inlet slit. The predicted aerosol flow in the DMA was affected by the width of inlet slit and the flow rate of sheath-air. The calculated results agreed with previous experimental results obtained by the flow visualization, in which the aerosol fed into the DMA was unevenly distributed along the circumference of the inlet slit when the slit width and the flow rate were large. The calculation also suggested that the nonuniform radial distribution of the aerosol near the inlet slit also affects the entire classification region of the DMA.
