|
|
Improving computational efficiency of contact solution in fully resolved CFD-DEM simulations with arbitrarily-shaped solids
Studeník, Ondřej ; Kotouč Šourek, M. ; Isoz, Martin
The abundance of industrial processes containing both solid and liquid phases generate demand for fully resolved models allowing for detailed analysis and optimization of these processes. An established approach providing such models is based using a variant of an immersed boundary method to couple the computational fluid dynamics (CFD) and discrete element method (DEM). In the talk, we will present our custom and monolithic implementation of a fully-resolved CFDDEM solver and concentrate on the intricacies of solving contact between two arbitrarily-shaped solids. We shall propose an efficient contact treatment based on the concept of a virtual mesh, which provides the mesh resolution required by DEM through dividing the space around the contact point in a finite volume fashion without any changes to the CFD mesh itself. A substantial part of the talk will devoted to the parallelization of the contact solution, especially in the context of the domain decomposition method imposed by the CFD solver.
|
|
|
Development, validation, and application of a solver for non-isothermal non-adiabatic packed bed reactors
Hlavatý, Tomáš ; Isoz, Martin ; Khýr, M.
Packed bed reactors are the most frequently used devices to perform heterogeneously catalyzed reactions on industrial scales. The main contribution of our work is the development of a numerical model applicable to simulations of such reactors. The developed model is based on the finite volume method, couples the momentum, mass and energy balances, and is free of any empirical closures. As such, the solver falls into the domain of the direct numerical simulation. In the talk, we will (i) present the new solver fundamental working principles, (ii) report on the verication of each of the solver components against existing literature data and (iii) demonstrate an application of the solver on an industrially relevant case of ethylene oxichlorination performed in a tubular reactor packed with Raschig rings coated by CuCl2 catalyst.
|
|
|
Model order reduction of transport-dominated systems with rotations using shifted proper orthogonal decomposition and artificial neural networks
Kovárnová, A. ; Isoz, Martin
In the present work, we concentrate on particle-laden flows as an example of industry-relevant transport-dominated systems. Our previously-developed framework for data-driven model order reduction (MOR) of such systems, the shifted proper orthogonal decomposition with interpolation via artificial neural networks, is further extended by improving the handling of general transport operators. First, even with intrusive MOR approaches, the underlying numerical solvers can provide only discrete realizations of transports linked to the movement of individual particles in the system. On the other hand, our MOR methodology requires continuous transport operators. Thus, the original framework was extended by the possibility to reconstruct continuous approximations of known discrete transports via another artificial neural network. Second, the treatment of rotation-comprising transports was significantly improved.
|
|
|
Implementation of wall functions into a hybrid fictitious domain-immersed boundary method
Kubíčková, Lucie ; Isoz, Martin
Hybrid fictitious domain-immersed boundary method (HFDIB) is a simulation approach used in computational fluid dynamics. The approach avoids usage of complex geometry-conforming computational domains. Instead, a simple domain is used and the geometry is projected onto it by a scalar field and adjustment of governing equations. Hence, the time spent on mesh generation is substantially reduced. It is advantageous to use the HFDIB in geometry optimizations where it allows for a massive optimization speed-up. Nevertheless, there is a problem with simulation of the fluid behavior in the boundary layer in the vicinity of the immersed walls. Especially, in simulation of highly turbulent flows, where the boundary layer is very thin and the usage of finer mesh is unaffordable. In this work, we aim to solve this problem by implementation of Reynolds averaged turbulence models in our custom HFDIB variant. In particular, we implemented the k-ω turbulence model and blended wall functions for closure variables and velocity.
|
guest ::
