Features of non-Boussinesq convection flows and their relevance to industrial applications

Flows caused by high-temperature (the so-called non-Boussinesq) convection play the major role in many industrial applications such as thermal insulation systems (nuclear reactors, heat generation stations), chemical vapour deposition (CVD) reactors for manufacturing electronic materials etc. The geometry of these applications is relatively simple, so that a parallel-wall channel or enclosure are the most common prototype configurations. Yet the arising flows exhibit complicated dependence on a large number of parameters such as the Reynolds number characterising the strength of a through-flow, Grashof number representing buoyancy effects and the temperature difference in the flow domain which affects fluid transport properties. As a result of strong nonlinearity of the governing equations, multiple flow patterns can exist for the same set of parameters. Which of the possible flow pattern sets in reality depends on initial conditions and, most importantly, for a certain range of the governing parameters, this can be controlled by a weak external excitation (e.g. by sound emitted from a speaker). This provides the way of externally influencing such practically important system characteristics as efficiency of thermal insulation, heat and mass transfer rates, chemical deposition rate and the uniformity of deposition. This talk will provide an overview of the major physical properties of high temperature convection-dominated flows closely relevant to industrial applications.