Course Details in 2023/24 Session


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Module Title LH Multiphase Systems
SchoolChemical Engineering
Department Chemical Engineering
Module Code 04 23624
Module Lead Dr P Cox
Level Honours Level
Credits 20
Semester Semester 1
Pre-requisites
Co-requisites
Restrictions None
Contact Hours Lecture-38 hours
Seminar-4 hours
Tutorial-34 hours
Supervised time in studio/workshop-2 hours
Guided independent study-122 hours
Total: 200 hours
Exclusions
Description This module introduces fundamentals enabling understanding of processing of multiphase systems.

Part 1: Colloidal systems and products

The interaction between colloidal drops/particles such as van der Waals and electrostatic forces are discussed and DLVO model is introduced; colloid stability including gas/liquid and liquid/liquid interfaces are discussed as well as measurements of zeta potential; different mechanisms of droplet break up. Emulsion stabilisation by small molecule emulsifiers and surfactants; steric and charge stabilisation; emulsion stability and destabilisation; rheology and rheology of suspensions; basic properties of suspension microstructure and how they affect rheology, viscoelastic fluids and use of simple viscoelastic models; momentum, mass and energy transfer in dispersed systems.

Part 2: Motion of particles in fluids and gas-liquid flow

Steady and un-steady state motion of particles/bubbles drag forces, add mass forces, skin friction and form drag are discussed for spherical and non-spherical particles; sedimentation, free and hindered settling as well as gas-liquid flow patterns in vertical and horizontal pipes including flow pattern maps are introduced; pressure drop in two-phase gas/liquid flow and homogeneous flow model, two-phase multipliers and separated flow model are introduced;

Part 3: Fluid/solids systems

Concept of maximum stable drop size in laminar and turbulent flow in stirred vessel and in pipes is introduced; coalescence and breakage model are discussed and related to dispersion processes; gas-solid fluidisations, pneumatic conveying, powder flow and consolidation are also introduced; stress/strain relationships;

Part 4: Lab

Generation of an emulsion: evaluation of stability, in particular considering creaming and coalescence over time. Completion of the appropriate report on stability based on measured experimental data (such as the droplet size distribution obtained by microscopy imaging analyses) obtained by all groups of students.
Learning Outcomes By the end of the module the student should be able to:
  • Evaluate the interactions of colloidal systems.
  • Identify the behaviour of dispersed phase in multiphase systems.
  • Apply relevant methods used in the description of multiphase systems to solve engineering problems.
  • Analyse the characteristics of the flow behaviour of gas/solid, gas/liquid and liquid/liquid systems.
Assessment 23624-05 : Exam : Exam (Centrally Timetabled) - Written Unseen (80%)
23624-08 : Lab Report : Coursework (20%)
Assessment Methods & Exceptions Assessment:

In semester assessment: 20%
Exam: 80%
Other None
Reading List Immiscible Liquid-Liquid Systems, in Handbook of Industrial Mixing: Paul, V. Atiemo- Obeng, S Kresta;
Intermolecular and surface forces, J. Israelachvili;
Processing of particulate solids, JPK Seville;
Bubbles, drops and particles, R. Clift, J.R. Grace and M.E. Weber;
Encyclopedia of Emulsion Technology vol 1, edit P. Becker;
Two-phase flow in pipelines and heat exchangers, D.Chisholm;