Study of formation and convective transport of aerosols using optical diagnostic technique

Abstract

The characteristics of liquid and solid aerosols have been intensively investigated by means of optical diagnostic techniques. Part I describes the characteristics of liquid aerosol formation formed by heat transfer fluids (HTFs) from bulk liquids. Part II investigates the characteristics of convective transport behavior of solid particles in virtual impactor (VI). The objective of part I is to establish correlations which offer predictions on atomized particle size of HTFs which are widely and commonly used in process industries. There are numerous reports stating that mist explosions formed from leakage cause disastrous accidents in process industries. For safety concerns, the characteristics of mist formation should be known in order to prevent HTFs from catching on fire or exploding. The empirical data on formation of mist are collected by the optical measurement technique, the Fraunhofer diffraction. The Buckingham-PI theorem is applied to establish a correlation between empirical data and representative physical properties of HTFs. Final results of correlations are solved by a statistical method of linear regression. The objective of part II is to investigate the characteristics of convective transport behavior in virtual impactor (VI) which is used to sort polydisperse precursor powder in the process industries of superconductor wire. VI is the device to separate polydisperse particles as a function of particle size by using the difference in inertia between different sizes of particles. To optimize VI performance, the characteristics of convective transport should be identified. This objective is achieved by visualization techniques. The applied visualization techniques are Mie-scattering and laser induced fluorescence (LIF). To investigate analytically, a local Stokes number is introduced in order to offer criteria on predicting the efficiency of VI performance and boundary effect on particle separation. The achieved results can enhance performance and eliminate defects by having knowledge of the behavior of solid particles in VI.