Investigation of the effect of turbulence on entropy generation in turbomachinery

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2014

Author

Orhan, Ömer Emre

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The aim of this thesis is to apply a newly developed methodology to calculate entropy production. Entropy production calculations have always attracted attention due to its extreme importance in efficiency improvement. Efficiency improvement can be achieved via several optimization techniques and Entropy Generation Minimization (EGM) is one of the most acknowledged ones. When it comes to the design and analysis of turbomachinery components, the performance deterioration due to various real flow effects such as secondary flows, profile losses or tip-leakage losses is generally represented through semi-empirical loss coefficients. Instead of relying on these coefficients one can use entropy generation rates as a consistent and quantitative measure of lost work due to irreversibilities, which can be calculated globally using the inlet and exit values of calculated pressures and temperatures of a system. However, if complete quantitative descriptions of velocity and temperature fields are available, one can compute field distributions of local viscous and thermal entropy generation rates by post-processing the available data. Another way of calculating entropy generation is possible using the combination of entropy transport equation with the positive definite entropy generation equation. In this study, a new entropy transport equation has been developed with the turbulence models and calculated using commercial CFD software. This new equation has been vi applied for the calculation of entropy generation around a gas turbine stator blade and the results have been compared with the results of the existing calculation methods.

Subject Keywords

Entropy., Turbulence., Turbomachines, Turbomachines

URI

http://etd.lib.metu.edu.tr/upload/12616870/index.pdf
https://hdl.handle.net/11511/23408

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

Ö. E. Orhan, “Investigation of the effect of turbulence on entropy generation in turbomachinery,” Ph.D. - Doctoral Program, Middle East Technical University, 2014.