Browsing by Author "Vass, Kane"

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    Performance analysis of a micro gas turbine engine using computational fluid dynamics
    (Stellenbosch : Stellenbosch University, 2023-03) Vass, Kane; Van der Spuy, S. J.; Van Eck, H.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH SUMMARY: Micro Gas Turbines (MGTs) are typically made up of a centrifugal compressor, combustor, axial turbine and exhaust nozzle combination. The aim of this thesis was to develop a complete numerical model of the CAT 250 TJ micro gas turbine in order to determine the operational performance characteristics of the engine. Computational Fluid Dynamics (CFD) was used to determine the operational requirements and the performance of the MGT compressor and turbine stages. The boundary conditions from these simulations were used to determine the required temperature gain over the combustor. A model of the combustor was developed that incorporated a combination of heat sources to emulate the energy release from combustion without modelling the physical combustion process directly. The use of these heat sources was found to provide an adequate temperature rise over the combustor region. A model containing the combustor, turbine stage and nozzle was then developed using conditions from the compressor outlet as the combustor inlet boundary condition. Experimental tests were performed using the same MGT to determine the performance parameters over the engines speed range. These performance parameters were compared to the simulated engine performance. It was found that at the design speed of 115 000 rpm, the simulated thrust and mass flow rate was 0.7% and 2.67% lower than the corrected experimental values at this speed. It was found that the use of these heat sources provide an approximate temperature distribution within the MGT and can be used to model the overall engine performance. An obvious next step would be to improve the modelling of the combustion process, in order to obtain a more accurate temperature distribution within the engine.