The emergence of closed-loop Brayton cycle power plants, such as the PBMR, resulted in the
need to simulate start-up transients for industrial multi-stage axial flow compressors operating at
subsonic conditions. This implies that the delivery pressure and power requirements must be
predicted for different mass flow rates and rotational speeds while operating in the first and fourth
quadrants on the compressor performance charts.
Therefore, an analytical performance prediction model for subsonic multi-stage axial flow
compressors had to be developed that can be integrated into a generic network analysis software
code such as Flownex. For this purpose, performance calculations based on one-dimensional
mean-line analysis demonstrated good accuracy, provided that the correct models for losses,
incidence and deviation are used. Such a model is therefore the focus of this study.
A preliminary analytical performance prediction code, with the capability of interchanging between
different deviation and loss models is presented. Reasonably complex loss models are
integrated in association with the correct incidence and deviation models in a software package
called "Engineering Equation Solver" (EES). The total pressure loss calculations are based on a
superposition of theoretically separable loss components that include the following: blade profile
losses, secondary losses and annulus losses. The fundamental conservation equations for
mass, momentum and energy for compressible "rotating pipe" flow were implemented into the
performance prediction code. Performance prediction models were validated against
experimental data and evaluated according to their ease of implementation. Verification was
done by comparing simulation results with experimental work done by Von Backstrom. This
includes a calculation to determine the uncertainty in the experimental results.
Furthermore, since the conventional definition of isentropic efficiency breaks down at the
boundaries of quadrants on the performance charts, a new non-dimensional power formulation is
presented that allows for the calculation of the compressor power in all of the relevant quadrants.
Good comparison was found between simulation results and measurements in the first and fourth
quadrant of operation. / Thesis (M.Ing. (Nuclear Engineering))--North-West University, Potchefstroom Campus, 2007.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/1271 |
| Date | January 2007 |
| Creators | Van Antwerpen, Werner |
| Publisher | North-West University |
| Source Sets | North-West University |
| Detected Language | English |
| Type | Thesis |
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