Biochemical Engineering


Fluid Flow and Mixing in Bioprocesses

Course Code
Level MSc
Credits 15 credits
Module Tutor
Dr Martina Micheletti
Three-hour examination (80%)
Coursework/ lab practical (20%)


To provide students with an introduction to the basic transport phenomena required to analyse and design processes handling labile biological materials. Focus is on the development of a physical understanding of the underlying momentum transport phenomena and upon the ability to apply transport analysis to practical bioprocess-oriented problems. The physical interpretation of the problem will be emphasised via the understanding of the problem’s mathematical solution.

Learning Outcomes

Following completion of the course, students will have an understanding of:

  • how to mathematically analyse and interpret given experimental data on a simple flow-related problem and provide a physical explanation of the results obtained.
  • how to design a generic flow system by verification of the assumptions made and quantify the pump requirements.
  • how to analyse and design a complete chromatography system based on fluid flow.
  • calculating the power input required for agitation in a stirred-tank fermenter under a range of operating conditions.
  • defining conditions for the successful scale-up or scale-down of a fermentation process.

Learning Hours


Lectures and case studies: 30h
Tutorials: 10h


  • Introduction and rheology: Definition of transport processes. Basic and derived units and nomenclature. Dimensionless numbers. Physics and maths revision. General aspects of rheology. Newton’s Law. Non-Newtonian fluids and rheology of fermentation broths. Viscosity measurement. Case study: cup and bob and viscometer.
  • Fluid flow in pipes: Predicting flow characteristics in pipe systems. Laminar flow and Hagen-Poiseuille equation. Calculating heads in a pipework system. Bernoulli equation. Case study: Bernoulli design problem. Pumping of Liquids (pumps classification, NPSH, cavitation, characteristic curve). Fluid flow and pressure measurement.
  • Fluid flow in packed columns: Flow through porous media. Darcy’s Law and Carman-Kozeny equation. Determining column porosity. Estimating pressure drops in packed beds.Effect of particle shape. Concept of wall support and effects of compressible media. Concept of critical velocity. Case study: Pumping and flow in chromatography columns.
  • Bioreactor mixing and scale-up/down: Mixing equipment, flow pattern and quantification of mixing phenomena in stirred tanks (power curve). Elements of fluid kinematics and turbulent flow scales. Case Studies: Design of batch sterilisation vessel, small aerated pilot fermenter, scale-up/down of fermenters.