Browsing by Author "Basson, Chenelle"
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- ItemAn investigation of the effect of inlet-swirl on the flow through a micro-gas turbine combustion chamber(Stellenbosch : Stellenbosch University, 2016-03) Basson, Chenelle; Meyer, Chris J.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: Previous research on the BMT120-KS micro-gas turbine engine has revealed that there is a component of swirl present at the compressor outlet. The effect of this inlet swirl on the flow through a micro-gas turbine combustion chamber is unknown. This project investigated the influence of the inlet swirl on the mass flow distribution and flow structures within the combustion chamber. An axial or non-swirl flow case was used as a control with which the swirling flow cases could be compared. Computational Fluid Dynamics (CFD) was used to investigate the mass flow distributions and internal flow structures of both the axial and the swirling flow cases. The axial and swirling mass flow distributions were determined experimentally as well. In order to determine the mass flow distribution experimentally with the test rig available at Stellenbosch University, certain assumptions were made. One assumption was that the pressure drop across the liner of the combustion chamber was constant along the liner. It was found that the experimental results validated the numerical results, with no more than 1.5 % difference for most of the sets of holes. The assumption was validated for the outer liner. However, the pressure drop over the inner liner varied with as much as 178 Pa, proving the assumption invalid. The discovery that the assumption was incorrect indicated that the experimental method was not accurate for this combustion chamber. However, it was concluded that the experimental results validated the numerical results, due to the good correlation obtained for the outer liner. The conclusion was made that the flow structures obtained numerically were a fairly accurate representation of the physical flow phenomena. When comparing the swirling flow cases to the axial flow case it was found that inlet swirl had a negligible influence on the mass flow distribution, but did have a negative impact on the flow structures within the combustion chamber. The recirculation zones for the swirling flow cases were not as well defined as for the axial flow case. It is therefore advised that the combustion performance be analysed with inlet swirl, in order to evaluate the effect of inlet swirl on the performance of the combustion chamber.