Turbulence, Plumes and Transport of Pollutants in Gases at Very High Temperatures

With this project, we propose an investigation into a variety of flow configurations driven by gravity (buoyancy convection) at very high temperatures and/or driving temperature gradients (by “very high temperatures” we mean one or more characteristic thresholds above which the standard concepts of the kinetic theory of gases, derived from classical mechanics, are no longer applicable). Applications involving such flows abound in the fields of thermal, mechanical, chemical, civil and nuclear engineering. Relevant examples include (but are not limited to) plumes from urban mass fires, the release in the atmosphere of smokes from industrial stacks and buoyancy convection in nuclear accidents. Applications involving such flows abound in the fields of thermal, mechanical, chemical, civil and nuclear engineering. Relevant examples include (but are not limited to) plumes from urban mass fires, fires in buildings and the release in the atmosphere of smokes from industrial stacks. Other significant examples are related to the cooling of high-power devices, solar energy and nuclear power plants, furnace engineering, the production of semiconductor and optoelectronics materials (where the processing itself requires that the high-temperature melt is in contact with a gas), etc.

The research will involve the development of new advanced numerical techniques. The new models shall also account for the transport of pollutants (in the form of ashes) or other toxic or hazardous substances.

At very high temperatures several effects conspire to make traditional models and standard CFD techniques inadequate and not suitable for treating these subjects. By “very high temperatures” we mean one or more characteristic thresholds above which the standard concepts of the kinetic theory of gases (derived from classical mechanics) are no longer applicable. Among them: the principle of energy equipartition, the Boussinesq approximation, the concept of fully excited molecular degrees of freedom, the Sutherland’s law, traditionally employed to account for changes in the gas viscosity, and similar analytic relationships for other fluid properties. In such circumstances gases may even undergo a dissociation process leading to a change in the chemical composition. Despite the perceived importance in other contexts (essentially hypersonic aerodynamics), these issues have not been adequately addressed for the case of low-speed compressible thermal flows.

It is expected that the student will critically upgrade existing methods and algorithms to account for the additional phenomena described above. Such tools will be then applied to circumstances of practical interest such as those outlined above.

Experience with OpenFoam or Ansys Fluent will be appreciated (but it is not strictly required)

[1] M. Lappa, (2016), A Mathematical and Numerical Framework for the Analysis of Compressible Thermal Convection in Gases at very high Temperatures, Journal of Computational Physics, 313: 687–712

[2] M. Lappa (2012), Rotating Thermal Flows in Natural and Industrial Processes, John Wiley & Sons, Ltd (2012, Chichester, England).

The opportunity is open to Home, EU and International applicants, who meet the required University of Strathclyde eligibility criteria. In particular the applicant must not have been awarded a previous Doctoral Degree.

In addition to the above, the applicant will hold, or in the process of obtaining, an integrated Master’s degree or equivalent in Mechanical Engineering, Chemical Engineering, Aeronautical or Aerospace Engineering, Physics, or another discipline related to the proposed research projects.