Large eddy simulation of the destruction of convecting hot fluid pockets through a cold channel flow

Abstract

Hot fluid pockets or hot spots can be found in many engineering systems, such as chemical reactors, internal heat engines and gas turbines. They are inherently fluid parcels with rapid temperature rising in comparison with the base medium and usually convect with the flow inertia. Due to the higher energy content, hot fluid pockets can change thermal characteristics of the system. Ignoring the destruction of them, which has been mainly missed in the literature, can therefore change the related predictions. The destruction of the hot fluid pockets is so investigated in this paper using a large eddy simulation and some statistical indices are used to reveal the coherence of the pockets. The results show that the convecting hot pocket can be significantly affected by hydrodynamic and thermal conditions, such that it may loss the initial tempo-spacial distribution completely. It is found that the hot spot behavior in lower Reynolds number range is not as regular as that at the higher Reynolds number range. Furthermore, the real thermal boundary conditions of convective heat transfer on the walls can completely change the destruction pattern in comparison to that in the adiabatic combustor. The extent of the destruction is various, depending on the flow conditions. The current results will help better prediction for systems involving hot fluid pockets.