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Sports car rear wing numerical optimization
Feldová, Petra ; Rudolf, Pavel (referee) ; Štefan, David (advisor)
This master’s thesis is focused on optimization of rear wing of sport car by using open-source software. The optimization of 2D profile of the rear wing is present in this thesis. Python environment was chosen for optimization and evolutionary algorithm was is used as optimization function. This algorithm is further connected to Xfoil software, which is computing aerodynamic characteristic. The ratio of the lift and drag coefficients (C_L/C_D) is chosen as parameter which considers the aerodynamic efficiency. The CFD computation of flowing around the whole car is provided in open-source software OpenFOAM. . The profile optimization results to approximately 7.9 % raise of the parameter C_L/C_D, in the same wing stability. The main benefit of this work is to use open-source software for the optimization and CFD analysis, which in future might save company’s resources by not buying expensive commercial software licenses.
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Model order reduction technique for large scale flow computations
Isoz, Martin
Current progress in numerical methods and available computational power combined with industrial needs promote the development of more and more complex models. However, such models are, due to their complexity, expensive from the point of view of the data storage and the time necessary for their evaluation. The model order reduction (MOR) seeks to reduce the computational complexity of large scale models. We present an application of MOR to the problems originating in the finite volume (FV) discretization of incompressible Navier-Stokes equations. Our approach to MOR is based on the proper orthogonal decomposition (POD)\nwith Galerkin projection. Moreover, the problems arising from the nonlinearities present in the original model are adressed within the framework of the discrete empirical interpolation method (DEIM). We provide a link between the POD-DEIM based MOR and OpenFOAM, which is an open-source CFD toolbox capable of solving even industrial scale problems. The availability of a link between OpenFOAM and POD-DEIM based MOR enables a direct order reduction for large scale systems originating in the industrial practice.
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Numerical simulation of flow in superpak family packings
Smutek, J. ; Isoz, Martin
The distillation is currently the most energy-intensive technology of the chemical industry. Commonly, the distillation is performed in the columns lled with a structured packing. Structured packings are complex structures used to increase the size of the interface available for the mass transfer. Because of the high complexity of both the packings and the physical phenomena occurring during the distillation, the design of the distillation columns is still based mostly on empirical data. In this work, we concentrate on modeling the gas ow in the SuperPak family of structured packings. First, we propose an algorithm for automatic generation\nof the packing geometry. Next, we construct and validate a three-dimensional computational uid dynamics (CFD) model of gas ow through SuperPak 250.Y and SuperPak 350.Y packings. The model validation is done by comparing experimental data of dry pressure losses to the values computed by our model. The obtained di erence between the CFD estimates and experiments is bellow 10 %. Finally, we present a parametric study of the SuperPak 250.Y packing geometry. The devised modeling approach may be easily automated and used for optimization of the SuperPak type packing geometry with respect to the gas ow. Furthermore,\nthe proposed CFD model may be extended to account for the multiphase ow.
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DEM-CFD study of flow in a random packed bed
Šourek, M. ; Isoz, Martin
Most catalytic surface reactions as well as other industrial applications take advantage of fixed packed bed reactors. Designers of these reactors rely mostly on empirical formulas derived for various simplifying assumptions, e.g. uniformly distributed porosity. The made simplifications and especially the assumption of uniformly distributed porosity fail if the tube to particle diameter ratio goes under 10 and the „wall effect“ becomes more significant. In such a case, the complete three-dimensional structure of the packed bed has to be considered. Thanks to ongoing improvements in numerical mathematics and computational power, the methods of computational fluid dynamics (CFD) have become a great tool for comprehensive description of the packed beds with low tube to particle diameter ratio. Three-dimensional simulations of the flow through two fixed beds differing in the type of the used particle are presented and compared with available experimental and empirical results. To generate the random fixed beds, we propose a custom approach based on the discrete element method (DEM) code implemented in open-source software Blender. Thereafter, OpenFOAM tools (snappyHexMesh, simpleFoam) are used for creation of the computational mesh and solution of the governing equations describing a single-phase flow in the packed bed.
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OCTAVE a OpenFOAM a jejich využití ve fyzice
VISKUP, Marian
The main goal of this bachelor thesis is to create a several examples of GNU Octave and OpenFOAM. To get acquainted myself with their usage and write short manuals for instalation and work with them for school subject Software for Scientific Computing, which is realized at the Faculty of Science, University of South Bohemia.
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CFD study of gas flow through structured separation columns packings mellapak 250.x and mellapak 250.y
Isoz, Martin
In order to increase the size of the gas-liquid interface area and consequently the intensity of the mass transfer, the separation columns are usually lled with a geometrically complex packing. The packing highly increases intricacy of the ow in the column and also makes almost all types of hydrodynamic measurements impossible. Hence a reliable model of the ow in the complex geometry of the separation column packing is sought by the industry. We provide a CFD model for the gas ow through two types of commercial structured packings, Mellapak 250.X and Mellapak 250.Y. We validate the model on experimental data and use it to study the gas mixing capabilities of the packings.
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CFD motivated applications of model order reduction
Isoz, Martin
The ongoing advances in numerical mathematics and available computing power combined with the industrial needs promote a development of more and more complex models. However, such models are, due to their complexity, expensive from the point of view of the data storage and the time necessary for their evaluation. The model order reduction (MOR) seeks to reduce the computational complexity of large scale models. We present an approach to MOR based on the proper orthogonal decomposition (POD) with Galerkin projection. The problems arising from the nonlinearities present in the original model are adressed within the framework of the discrete empirical interpolation method (DEIM). The main contribution of this work consists in providing a link between the POD-DEIM based MOR and OpenFOAM. OpenFOAM is an open-source CFD toolbox capable of solving even industrial scale processes. Hence, the availability of a link between OpenFOAM and POD-DEIM based MOR enables a direct order reduction for large scale systems originating in the industrial practice.
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Intake vortex modeling
Galuška, Jiří ; Kozák, Jiří (referee) ; Rudolf, Pavel (advisor)
This paper covers information research of basic design rules of industrial wet sumps. It describes mathematical models of vortices and method for their identification and visualization. Then the author focuses on CFD modeling of surface vortices with single phase and multiphase approach with Volume of Fluid method. Basic principles of multiphase CFD modelling in OpenFOAM and ANSYS Fluent are given. Description and benchmarking of suitable turbulence models is also present. The single phase and multiphase approach were successfully validated for a simple test case of bathtub surface vortex. Satisfactory agreement with experimental data was achieved. The accuracy and behavior of both solvers were compared between each other. This gives us useful tool for evaluation of inflow condition and danger of surface vortex occurrence in wet sumps. The acquired knowledges were used to design an experimental test case with geometry similar to industrial wet sump. A map of surface vortex occurrence has been created for different operating points. One of the operating point has been used for numerical simulation (both single phase and multiphase). Partial agreement with experimental observation has been achieved.
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Modelling of the Laminar/Turbulenttransition on a Heated Flat Plate Using the k-kL-w Model
Kožíšek, Martin ; Fürst, J. ; Příhoda, Jaromír
The contribution deals with the numerical simulation of the transition to turbulence on a heated flat plate by means of the k-kL-k-kL-w model of Walters and Cokljat (2008). The revised version of the three-equation model was implemented into the OpenFOAM code for the incompressible and compressible flows. Numerical simulations of the boundary-layer development were carried out according to measurements of Sohn and Reshotko (1991). The transition model was tested by means of the skin friction and the Stanton number distributions for various free-stream turbulence levels. Results were compared with empirical correlations expressing the Reynolds analogy according to Kays and Crawford (1993) and with experimental data of Pinson and Wang (2000).
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