Influence of Turbulent Diffusion in an Electrical Mobility Spectrometer
Electrical mobility spectrometer (EMS) is one of most commonly used instruments for measuring the distribution of nanometer-sized aerosol particles. Typically, the EMS has a particle charger, an electrical mobility classifier, and an electrometer. Its principle of operation of is the following: The aerosol to be tested is charged by a unipolar diffusion charger and then classified by electrical mobility in the classifier, which consists of coaxial cylindrical electrodes. The inner electrode is at a high voltage and deflects the charged particles in the flow field toward the outer electrodes. These then collect the particles only within narrow bands of the overall mobility spectrum of the aerosol. In an ideal case, as the charged particles in the classifier move along precisely determined trajectories, they produce the true mobility spectrum. Practically however, molecular and turbulent diffusion randomly scatters the trajectories of the particles, giving a smoothed mobility spectrum. The degree of smoothing can be characterized by the resolution. Fortunately, molecular diffusion submits itself relatively well to a theoretical description and the analytical equation expresses the resolution of the EMS. Because of the complexity of turbulent diffusion, simplifying assumptions were made for this work. The EMS resolution values were calculated based on expected turbulence parameter data.
Aerosol Diffusion Mobility Spectrometer Nanoparticles Turbulence
Jaan Salm Panich Intra Artit Yawootti Nakorn Tippayawong
Institute of Physics,University of Tartu,Tartu 50090,Estonia College of Integrated Science and Technology,Rajamangala University of Technology Lanna,Chiang Mai 5 Department of Mechanical Engineering,Faculty of Engineering,Chiang Mai University,Chiang Mai 50300,T
国际会议
西安
英文
962-966
2011-08-17（万方平台首次上网日期，不代表论文的发表时间）