For many years, Concepts NREC has offered a course on axial and radial turbine design for practicing engineers and students of turbomachinery presented by the authors of this volume. The present book has been developed from that. It is, however, very much more than a simple reprinting of the course notes. Great effort has been made to produce a book that presents a complete, coherent, and up-to-date account of the design and analysis of axial and radial turbines. Overview
During service, a turbine engine undergoes frequently dynamic operations. Because of the changes in mass flow, temperature, pressure, as well as the different reaction of the components of turbine to these changes, the turbine performances may vary significantly. It is critical to understand and quantify these variations to design and integrate the turbine to the engine. This paper presents a study of the performances and the variation of the performances for an axial gas turbine across its operating envelope. Numerical simulations are used to describe the flow across the turbine and to estimate the turbine maps. Using theoretical charts for typical turbine thermal expansion, the variation of tip clearance across the working line is approximated. Because of the changes of the tip clearance, using a single geometry may not supply relevant information during real dynamic operations. In order to eliminate these additional errors in the numerical study, a number of turbines maps are recalculated for different tip clearances, respectively to engine regimes. With the resulting data, the working line is recalculated across multiple maps. The comparison between the two working lines is presented as well as the study of performance variation of the turbine across the operation envelope and the influence of tip clearance at different regimes.
Axial And Radial Turbines By Hany Moustapha.pdf
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