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Fitting and Extrapolation of Turbocharger Turbine Maps
Vondrák, Adam ; Babák, Martin (oponent) ; Novotný, Pavel (oponent) ; Štětina, Josef (vedoucí práce)
Modelling of turbine performance is a prerequisite for detailed simulation of gas exchange in turbocharged combustion engines. At the same time, the possibility to determine efficiency and mass flow capacity at arbitrary operating points is key to comparing different turbine stages. The objective of this work is to propose a single method for both purposes, so it is possible to do the comparison using exactly the same turbine performance model as in subsequent engine working cycle simulation. The source of input data is typically a gas stand measurement, which enables capturing of limited turbine operating range only. In this work, methods are proposed to improve the fidelity and robustness of turbine performance extrapolation, while optimization is employed to find the best fit in terms of agreement between the model and the input data.
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Fitting and Extrapolation of Turbocharger Turbine Maps
Vondrák, Adam ; Babák, Martin (oponent) ; Novotný, Pavel (oponent) ; Štětina, Josef (vedoucí práce)
Modelling of turbine performance is a prerequisite for detailed simulation of gas exchange in turbocharged combustion engines. At the same time, the possibility to determine efficiency and mass flow capacity at arbitrary operating points is key to comparing different turbine stages. The objective of this work is to propose a single method for both purposes, so it is possible to do the comparison using exactly the same turbine performance model as in subsequent engine working cycle simulation. The source of input data is typically a gas stand measurement, which enables capturing of limited turbine operating range only. In this work, methods are proposed to improve the fidelity and robustness of turbine performance extrapolation, while optimization is employed to find the best fit in terms of agreement between the model and the input data.
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Optimization of the Stator Vane Aerodynamic Loading for a Turbocharger with a Variable Nozzle Turbine
Žatko, Miroslav ; Rudolf, Pavel (oponent) ; Babák, Martin (oponent) ; Malenovský, Eduard (vedoucí práce)
The purpose of this thesis is the investigation and optimization of the aerodynamic loading acting on the stator vanes of the turbocharger using variable nozzle turbine. Computational fluid dynamics is applied using commercial software ANSYS CFX. A full turbine stage CFD model is used to investigate the stator vane aerodynamic loading in several operating points for different stator vane positions. Impacts of the volute pressure distribution, the vane rotation angle and the spacer pins are well described and evaluated for several boundary conditions. An experimental device is then introduced to perform in situ measurement of aerodynamic loading with the use of the Gas Stand testing rig. This burns natural gas producing a very stable flow conditions at very high temperatures. It excludes the impact of the engine control management, the engine vibrations and the flow pulsations on measured values. Results are compared with the full stage CFD analysis and very good correlation is achieved. Validated CFD model is then simplified using cyclic symmetry boundary condition and reduced to only one segment of the stator and rotor. This enables to rapidly increase productivity of the simulation and enables to explore impact of several stator design parameters in full range of vane movement. Presented sensitivity study build up very good background for further optimization process and identify several areas for potential improvement. Definition of the ideal aerodynamic loading is then presented based on analysis of the turbocharger requirements and it is established as a target for optimization study. Several optimization strategies using force vector analysis method are then presented. Results are compared and analyzed from several different perspectives. Final optimized solution is then validated by the full stage CFD calculation. This confirms excellent behavior of aerodynamic loading in hand with improvement of low end efficiency.
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Hodnocení tržního potenciálu pro vstup nového franchisingového řetězce
Babák, Martin
Cílem bakalářské práce je navržení strategie pro vstup nového franchisingového řetězce Denny's na trh. Hlavní část práce se zaměří na analýzu marketingového prostředí. Na analýzu bude využit Porterův pětifaktorový model a PEST analýza. S využitím SWOT analýzy budou identifikovány silné a slabé stránky společnosti a příležitosti a hrozby trhu. Dílčím cílem je provedení analýzy s posouzením tržního potenciálu. K formulaci návrhů a doporučení poslouží data z marketingového průzkumu.
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