Droplets as precursor are extensively applied in diverse fields of science and engineering. Various contributions are provided previously towards analysis of single phase and multi-phase droplets of single and multiple components.
This thesis describes modelling of multi-phase (nano fluid) droplet vaporization. The
evaporation of liquid phase along with migration of dispersed particles in two-dimensional plane within droplet is detailed using the governing transport equations
along with the appropriate boundary and interface conditions.
The evaporation model is incorporated with aggregate kinetics to study agglomeration
among nano silica particles in base water. Agglomeration model based on population
balance approach is used to track down the aggregation kinetics of nano particles in
the droplet. With the simulated model it is able to predict different types of final
structure of the aggregates formed as observed in experimental results available in
literature. High spatial resolution in terms of agglomeration dynamics is achieved
using current model. Comparison based study of aggregation dynamics is done by
heating droplet in convective environment as well as with radiations and using
different combination of heating and physical parameters. The effect of internal flow
field is also analysed with comparative study using levitation and without levitation
individually. For levitation, droplet is stabilized in an acoustic standing wave.
It is also attempted to study the transformation of cerium nitrate to ceria in droplets when heated under different environmental conditions. Reaction kinetics based on modified rate equation is modelled along with vaporization in aqueous cerium nitrate droplet. The thermo physical changes within the droplet along with dissociation
reaction is analysed under different modes of heating. The chemical conversion of
cerium nitrate to ceria during the process is predicted using Kramers' reaction velocity
equation in a modified form. The model is able to explain the kinetics behind
formation of ceria within droplet at low temperatures. Transformation of chemical
species is observed to be influenced by temperature and configuration of the system.
Reaction based model along with CFD (computational fluid dynamics) simulation
within the droplet is able to determine the rate of chemical dissociation of species and
predict formation of ceria within the droplet. The prediction shows good agreement
with experimental data which are obtained from literature.
| Identifer | oai:union.ndltd.org:IISc/oai:etd.iisc.ernet.in:2005/3318 |
| Date | January 2013 |
| Creators | Pathak, Binita |
| Contributors | Basu, Saptarshi |
| Source Sets | India Institute of Science |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
| Relation | G25686 |
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