Browsing by Author "Schommarz, Timmo Marc"

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    Analysis, design and manufacturing of solarised gas turbine compressor
    (Stellenbosch : Stellenbosch University, 2019-04) Schommarz, Timmo Marc; Von Backstrom, T. W.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering (CRSES)
    ENGLISH ABSTRACT: An existing three-dimensional fluid mechanical design of a compressor is reviewed and compared to mean-line simulation results obtained using the Comp- Aero® compressor design code. Mean-line simulation results give a compressor total-to-static pressure ratio of 3.2. The three-dimensional CFD analysis performed using ANSYS CFX® calculates a total-to-static pressure ratio of 3.4. This is an increase of 31% from the pressure ratio of the currently installed compressor (2.6). ANSYS Mechanical® is used to perform finite element analyses for deformation, stress and vibrational behaviour. The maximum calculated axial deflection is 0.24 mm. The calculated maximum equivalent stress is 218 MPa. All vibration modes occur at frequencies higher than the operating speed of the compressor. The first damped frequency occurs at 837 Hz which represents and over-speed condition of 9.24%. Over-speed simulations to 110% operating speed calculate a maximum stress in the impeller of 264 MPa. This is 1.8 times less than the yield strength of Aluminium 7075 which was used to manufacture the part. Axial forces due to the increased outlet pressure of the compressor are calculated. The total load on the angular contact bearing increased from 376 N, as experienced with the old compressor, to 955 N when using the new compressor. The new impeller and diffuser are designed using the Autodesk Inventor® CAD program. The components are machined using five- and three-axis computer-aided milling.