Известия Томского политехнического университета: Инжиниринг георесурсов (Apr 2018)
Sedimentation rates of fine aerosols in acoustic and electric field
Abstract
The relevance of the research is related to searching the efficient ways of deposition of fine aerosols to clean production rooms from dust and smoke. Development of methods of ensuring purity of air environment in production rooms are especially relevant in connection with the development of nanotechnologies as well as engineering chemistries, related to possible emissions of harmful and dangerous dust. The main aim of the research is searching for optimum ways of deposition of fine aerosols comparing electrostatic and ultrasonic deposition of particles. Objects of the research are fine aerosols and ways of their deposition. Methods: mathematical modeling, optical methods of measurement of distribution function of particles by the sizes and concentration of aerosol particles using the laser measuring system LID2M and the Malvern Spraytec analyzer. Results. The authors have carried out the theoretical analysis of sedimentation rates of particles of fine aerosols (diameter of particles ~1-20 µm) in the presence of acoustic, electric field taking into account a drift in electric field, ultrasonic coagulation, and acoustic flows («sound wind»). The key mechanisms of particles deposition depending on their size are defined that allows proposing the optimum ways of deposition of fine aerosols in each range of particle sizes. The mathematical model of acoustic coagulation is based on an integral form of the equation of Smolukhovsky. The paper introduces the results of the experimental study of the model aerosol (NaCl) particles deposition with the reference diameter of particles about 6 µm by means of ultrasound and electrodeposition device. It is defined that application of these ways of deposition is essential (and it is approximately identical) and it accelerates considerably sedimentation of the model aerosol that corresponds to theoretical results. On the other hand, theoretical calculations predict that application of electrostatic way of deposition will be more effective in comparison with the ultrasonic one for aerosols with rather larger particles.
