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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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Optimization of the Stator Vane Aerodynamic Loading for a Turbocharger with a Variable Nozzle Turbine
Žatko, Miroslav ; 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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