Multi-scale Modeling and Simulations of Multi-phase Flows

Third Party Funds Group - Sub project

Overall project details

Overall project: Multiscale Modelling, Simulation and Optimization for Energy, Advanced Materials and Manufacturing

Overall project speaker:
Prof. Dr.-Ing. Paul Steinmann (Lehrstuhl für Technische Mechanik)

Project Details

Project leader:
Prof. Dr. Ulrich Rüde

Project members:
Dominik Bartuschat

Contributing FAU Organisations:
Lehrstuhl für Informatik 10 (Systemsimulation)

Funding source: Deutscher Akademischer Austauschdienst (DAAD)
Start date: 01/01/2016
End date: 31/12/2020

Abstract (technical / expert description):

Availability of adequate, clean and affordable energy is critical for realizing basic human needs and further economic development. Modern society is heavily dependent on electricity (industry, lighting, transportation, communications and so on). The current energy systems are mainly dependent on fossil carbon (oil, gas and coal). According to the recent world electricity generation statistics (see, about 42% of the energy is generated using coal. In India, the share of coal in electricity generation is more than 60% ( Considering this, any efforts in expanding the energy availability are bound to increase the environmental impact (carbon footprint, water footprint, impact on human health). In addition, coal power plants are proven to have the highest impact on human health among the electricity production processes. It is therefore essential to make every effort to reduce the environmental footprint of energy systems and develop more efficient and cleaner energy generation technologies. In the conventional pulverized coal (PC) based power plants, coal combustion is used to generate steam and then electricity. In contrast, in coal gasification based systems, the coal is converted into syngas (mainly CO, H2) which can be easily cleaned and then converted into either electricity via the IGCC (Integrated Gasification Combined Cycle) route or into synthetic fuels (gasoline, diesel, etc.). Owing to local availability of biomass, it is also desired to gasify the biomass or co-gasify it with coal for generation of electricity locally.

There are several challenges in improving the performance of the coal combustion boilers or in development of IGCC based power generation process using coal or biomass or a mixture of coal and biomass. Most of the processes employ one or other type of fluidized bed and one of the important challenge is efficient design of fluidized bed gasifiers for gasification coal or biomass or a mixture of coal and biomass. In order to develop simulation tools that can be used for design, scale-up and performance optimization of large-scale coal-fired boilers or gasifiers, it is important to understand the fluidization behavior of binary particle mixtures with varying size, shape and density.

In addition to coal based energy (power generation or liquid fuels), there are several important applications that involve gas-liquid flow through packed beds, for example, in oil refining industry for trickle bed reactors used for removal of Sulfur from liquid fuels, gas-liquid absorption columns, etc. In all such processes, it is important to understand how the local liquid distribution changes as a function of local porosity, surface wettability characteristics. It is therefore important to develop computational tools that can simulate gas-liquid flow in packed beds.

One objective of this project to perform Lattice-Boltzmann simulations of unary and binary particulate flows, with a large number of particles, to understand the effects of particle size, shape and density on fluidization characteristics (flow regimes, bubbling characteristics, solid volume fraction, mixing & segregation characteristics) . The numerical results will be validated with high-speed visualization imaging experiments to characterize fluidization behavior of unary and binary particles and also to perform continuous phase velocity flow field measurements using Time-Resolved Particle Image Velocimetry (TR-PIV). Furthermore, direct numerical simulations (DNS) of unary and binary particles with smaller number of particles will be carried out to derive the closure models for Eulerian (continuum) simulations. Additionally, simulations of gas-liquid two-phase flow through geometrically resolved packed beds will be performed and compared with high-speed visualization imaging and Particle Image Velocimetry experiments to characterize flow of gas and liquid phases through small specimens of liquid filled packed beds.

The expected outcomes of this project are experimentally validated computational models to simulate unary and binary particulate flows and the development of closures for continuum (Eulerian) models for simulation of binary particles based on direct numerical simulations. Furthermore, a deeper understanding of particle-particle interactions and the effects of particle properties (size, shape, density, etc.) on dynamic characteristics of fluidization and mixing/segregation of binary particles is aspired. Also the effects of particle size/shape, bed porosity and surface characteristics on local velocity flow fields and gas-liquid distribution will be analyzed

External Partners

Indian Institute of Technology (IIT), Delhi

Last updated on 2019-22-05 at 10:17