scholarly journals A pressure-based diffuse interface method for low-Mach multiphase flows with mass transfer

2022 ◽  
Vol 448 ◽  
pp. 110730
Author(s):  
Andreas D. Demou ◽  
Nicolò Scapin ◽  
Marica Pelanti ◽  
Luca Brandt
Author(s):  
Bahman Aboulhasanzadeh ◽  
Siju Thomas ◽  
Jiacai Lu ◽  
Gretar Tryggvason

In direct numerical simulations (DNS) of multiphase flows it is frequently found that features much smaller than the “dominant” flow scales emerge. Those features consist of thin films, filaments, drops, and boundary layers, and usually surface tension is strong so the geometry is simple. Inertia effects are also small so the flow is simple and often there is a clear separation of scales between those features and the rest of the flow. Thus it is often possible to describe the evolution of this flow by analytical models. Here we discuss two examples of the use of analytical models to account for small-scale features in DNS of multiphase flows. For the flow in the film beneath a drop sliding down a sloping wall we capture the evolution of films that are too thin to be accurately resolved using a grid that is sufficient for the rest of the flow by a thin film model. The other example is the mass transfer from a gas bubbly rising in a liquid. Since diffusion of mass is much slower than the diffusion of momentum, the mass transfer boundary layer is very thin and can be captured by a simple boundary layer model.


Author(s):  
Tatyana Lyubimova ◽  
Olga N. Goncharova ◽  
Alexander Kupershtokh

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 815
Author(s):  
Arne Teiwes ◽  
Maksym Dosta ◽  
Michael Jacob ◽  
Stefan Heinrich

Although the benefits of pulsating multiphase flows and the concomitant opportunity to intensify heat and mass transfer processes for, e.g., drying, extraction or chemical reactions have been known for some time, the industrial implementation is still limited. This is particularly due to the lack of understanding of basic influencing factors, such as amplitude and frequency of the pulsating flow and the resulting particle dynamics. The pulsation generates oscillation of velocity, pressure, and temperature, intensifying the heat and mass transfer by a factor of up to five compared to stationary gas flow. With the goal of process intensification and targeted control of sub-processes or even the development of completely new processing routes for the formation, drying or conversion of particulate solids in pulsating gas flows as utilized in, e.g., pulse combustion drying or pulse combustion spray pyrolysis, the basic understanding of occurring transport processes is becoming more and more important. In the presented study, the influence of gas-flow conditions and particle properties on particle dynamics as well as particle residence time and the resulting heat and mass transfer in pulsating gas–solid flows are investigated.


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