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Particle Dynamics in Thermally Driven Flows

We propose an investigation into a variety of dynamics and effects produced by the interaction of particles with fluid flow driven by a temperature gradient. Related technological applications abound in the fields of thermal, mechanical, nuclear and chemical engineering (at several scales).

Number of places

One

Opens

18 September 2018

Eligibility

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, Materials Science, Materials Engineering, Metallurgy, Aeronautical or Aerospace Engineering, Physics, or another discipline related to the proposed research projects.

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

 

Project Details

This project will concentrate on "new" mechanisms discovered recently about the dynamics of inertial particules in thermogravitational, thermocapillary or thermovibrational flows

Complex fluids are binary mixtures that have coexistence between two phases. Such fluids are not only of fundamental interest but they are also of practical importance with applications in a variety of areas (mechanical, chemical, petrochemical, nuclear, energy, inorganic and organic materials, ocean, mineral and electronics and micro-electronics engineering, information technology, space technology, micro- and nano-technologies, biomedical and life sciences). As an example, many (e.g., metal) alloys, before being solid, pass through a liquid or fluid state, which involves the coexistence of different (immiscible) phases [1]. Similar considerations also apply to organic materials (e.g., proteins and other macromolecular substances), which are produced in the form of “seeds” nucleating in a supersaturated liquid [1]. The ability to control the dynamics of the dispersed phase is regarded, in general, as a factor of crucial importance for the optimisation of several industrial processes and/or for the elaboration of completely new (inorganic or organic) materials. These concepts are also relevant to nanotechnologies and related products. Self-assembly and induced clustering of solid particles dispersed in a fluid are emerging as one of the main methods for construction of heterogeneous systems consisting of multiple component types in nano- and micro-scales (e.g. “lab-on-chip” devices).

The main overarching principle governing the transport of solid particles in fluid flow is that, because of “inertial effects”, a set of particles when transported by a fluid can behave as a “compressible medium”, i.e. the spacing among particles can change significantly, even if the surrounding fluid and carrier flow are incompressible. This remarkable property can produce fluctuations of concentration of the dispersed matter and, hence, support mechanisms for particle accumulation and ordering.

With this project, we propose an investigation into a variety of dynamics and effects produced by the interaction of particles having non-negligible size and mass (“inertial particles”) with flows produced by buoyancy, surface-tension-driven effects or vibrations [2,3,4].

The research will involve the application of both numerical and experimental techniques (70%+30%). For the experiments, in particular, the student will take advantage of the recently developed facilities, available at the James Weir Fluid Labs, by which it is possible to investigate both thermogravitational and thermocapillary flows at various scales. The student will also be trained to use laser-based and optical techniques for flow visualization. From a numerical-simulation standpoint, the student will be trained to use OpenFoam and other numerical codes available at the Department of Mechanical and Aerospace Engineering.

[1] Lappa M., (2004), “Fluids, Materials and Microgravity”, 538 pages, Elsevier Science (2004, Oxford, UK)

[2] Lappa M., (2018), On the transport, segregation and dispersion of heavy and light particles interacting with rising thermal plumes, Physics of Fluids, 30(3), 033302 (23 pages).

[3] Lappa M., (2013), Assessment of the role of axial vorticity in the formation of Particle Accumulation Structures in supercritical Marangoni and hybrid thermocapillary-rotation-driven flows, Phys. Fluids, 25(1), 012101.

[4] Lappa M., (2017), On the multiplicity and symmetry of particle attractors in confined non-isothermal fluids subjected to inclined vibrations, Int. J. Multiphase Flow, 93: 71-83.

Funding Details

This project is unfunded, and therefore would be suitable to eligible applicants with self funding, or with the possibility of other sources of funding. However, funding may be available for Home (UK) students who meet the requirements to be selected in the framework of the "Doctoral Training Partnership" of the University of Strathclyde with Engineering and Physical Sciences Research Council (EPSRC)

Further information

From a theoretical point of view, training will be provided with regard to 1) the general background (importance of this kind of research and potential practical applications), 2) governing parameters, 3) gravitational phenomena in multiphase flows, 4) Marangoni thermal effects, 5) Vibrational effects in multiphase systems, 6) Multiscale modeling, 8) Particle-tracking Numerical Methods. From a practical standpoint, the student will be trained to use available numerical tools. From an experimental standpoint, the student will be trained to investigate particle dynamics in different circumstances. It is expected that such a wide spectrum investigation will provide the student with the necessary skills to address in the future more complex problems of technological interest.

How to apply

 

Please email a covering letter and CV  directly to Dr Marcello Lappa, Department of Mechanical and Aerospace Engineering,  for consideration