Physics projects for Y3 and Y4 students

Project description

Dispersion and segregation of suspensions

(supervisor: Rudi Winter)

Nature of project: experimental, data analysis

Available to students on full-time physics degree schemes or joint students.

Project description and methodology

Mechanical action is effective in both dispersing particles in a liquid and in segregating the resulting suspension into its solid and liquid components. Stable suspensions are important in many technological processes, e.g. when fine particles need to be applied to a substrate very evenly. On the other hand, if a liquid is used to collect a solid material, the suspension needs to be forced to segregate in order to harvest the solid, for example using a centrifuge.

This project looks at both processes (perhaps focussing on one more than the other for half projects) and aims to investigate the effect parameters such as ambient temperature, viscosity and solid-liquid interactions have on the stability of suspensions. The results will be interpreted in terms of thermodyamic and kinetic factors.

A successful project will develop beyond the above in one/some of the following directions:
The project can be developed towards investigating phase transitions between mixed and de-mixed states, with an estimation of the entropy of mixing as a function of parameters like particle size and mass.

Another development could be concerned with the role of surface tension on the dispersion or segregation process by investigating different liquids or the use of detergents to modify the contact forces between the solid and liquid phases.

When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.

This project is only available as a Y3 project.

Please speak to Rudi Winter if you consider doing this project.

Initial literature for students:

  1. JF Morris; Rheol Acta 48 (2009) 909
  2. ELPV Atiemo-Obeng, SM Kresta; Handbook of Industrial Mixing Science and Practice; Hoboken: Wiley (2004)
  3. S Ramakrishnan et al.; J Chem Phys 116 (2002) 2201

Novelty, degree of difficulty and amount of assistance required

This is a fairly well studied field, allowing for comparison of results with literature data. However, it will be possible to extend the parameter range in different directions, which offers the opportunity to learn new facets of suspension behaviour.

Project milestones and deliverables (including timescale)

milestoneto be completed by
Identify suspension to studyend of November
Plan and prioritise parameter spaceChristmas
Comprehensive experimental coverage of parameter spacemid-March
Comparison with literature data for similar systemsEaster

Students taking this project will have to submit a full risk assessment form