Design of experimental apparatus for generation and measurement of an aerosol

Abstract

This work is done as a requirement for the master's degree. In this work, a system for generating aerosol delivery into shock tube for interface creation and a method to measure aerosol is developed. In chapter 1, a brief introduction of hydrodynamic instabilities later focussing on shock driven multiphase instabilities (SDMI) and its importance is presented. SDMIs have similar flow morphology to the Richtmeyer-Meshkov Instability (RMI), however, the driving force that induces instability is different. Current methods of aerosol production and measurement with pros and cons are given to justify the adaption of the selected method for our system. Chapter 2 discusses about the theory of ultrasonic atomization and evidence of faraday instability for atomization. Later setup of aerosol delivery system with two different set of atomizers is presented. In chapter 3, Laser interferometry principle and apparatus used for the measurement of aerosol with the consideration of various factors is given. To avoid Mie scattering theory's intense use of calculations Geometrical optics approximation method is used which agrees well with the Mie theory for all the particles above 1µm. Chapter 4 presents experimental results of measurement which includes particle size distribution, density measurement of aerosol. Later it presents the experimental results when the aerosol is used for the study of SDMI. Two different cases, one with the low effective Atwood number and the other with higher effective Atwood number are investigated. In the case of low effective Atwood number the instability evolved is more like RMI rather than SDMI which is due to domination of Gas Atwood number over effect Atwood number. Last case with higher effective Atwood number of 0.03 with shock wave of Mach 1.66 is investigated, to find out that flow morphologies are in good agreement with literature and simulations. Chapter 5 gives conclusion of the research studies and future research.