Abstract

Gas turbines are a major contributor to world power generation with applications ranging from electricity production to aircrafts propulsion. Their efficiency is subject to continuous research. A gas turbine's overall efficiency is directly proportional to flow inlet temperature. Various methods are implemented to protect hot gas path components from mainstream flow well above their melting temperature, namely, heat resistant coatings, internal cooling and film cooling. The latter is the subject of this work. A 3-D Computational Fluid Dynamics (CFD) model is solved using ANSYS CFX software and compared to experimental measurements of film cooled transonic vane cascade operating at a Mach number of 0.89; the experimental data used for validation is provided by Heat and Power Technology Department of the Royal Institute of Technology (Kungliga Tekniska Högskolan, KTH) of Stockholm, Sweden. A new approach was used to model the film cooling holes, omitting the need to model both the coolant plenum and cooling tubes, resulting in 180% reduction in grid size and attributed computational cost interpreted in 300% saving in computation time. The new approach was validated on a basic flow problem (flat plate film cooling) and was found to give good agreement with experimental measurements of velocity and temperature at a blowing ratio (BR) of 1 and 2; the experimental data for the flat plate was provided by NASA's Glenn Research Center. The numerical simulation of the cooled vane cascade was compared to experimental measurements for different cooling configurations and different BRs. a) One row on pressure side at BR = 0.8, 0.96 and 2.5. b) Two rows on suction side (location 1) at BR = 0.8, 1.4 and 2.5. c) Two rows on suction side (location 2) at BR = 0.8. And d) Showerhead cooled vane at BR ranges between 1.98 and 5.84. The coolant was applied at the same temperature as the mainstream, to match experimental conditions. A good agreement with the experimental measurements was obtained for exit flow angle, vorticity downstream of the vane, pressure coefficients and aerodynamic loss. The proposed approach of coolant injection modeling is shown to yield reliable results, within the uncertainty of the measurements in most cases. Along with lower computational cost compared to conventional film cooling modeling approach, the new approach is recommended for further analysis for aero and thermal vane cascade flows.

Department

Mechanical Engineering Department

Degree Name

MS in Mechanical Engineering

Date of Award

2-1-2014

Online Submission Date

January 2014

First Advisor

El-Gabry, Lamyaa

Committee Member 1

Serag El Din, Mohamed Amr

Committee Member 2

Fouad, Mahmoud

Document Type

Thesis

Extent

85 p.

Library of Congress Subject Heading 1

Computatiol fluid dymics.

Library of Congress Subject Heading 2

Aircraft gas-turbines.

Rights

The author retains all rights with regard to copyright. The author certifies that written permission from the owner(s) of third-party copyrighted matter included in the thesis, dissertation, paper, or record of study has been obtained. The author further certifies that IRB approval has been obtained for this thesis, or that IRB approval is not necessary for this thesis. Insofar as this thesis, dissertation, paper, or record of study is an educational record as defined in the Family Educational Rights and Privacy Act (FERPA) (20 USC 1232g), the author has granted consent to disclosure of it to anyone who requests a copy.

IRB

Approval has been obtained for this item

Comments

I would like to start by praising Allah, for his guiding hand has always pointed me in the right direction and lead me through times of uncertainty, query and ambiguity. Then my sincerest thanks are for my supervisor, Dr. Lamyaa El-Gabry, for the continuous guidance and support she provided throughout the time of this work. Her intellect and erudition make her one of the most versed professors I have met in my educatiol life, which was interpreted in clearer and paved path for me in my work. And thanks to Dr. Jens Fridh and Ranjan Saha of the Energy department at KTH Royal Institute of Technology who made this research possible through providing data and guidance. And the very informative and enlightening online meetings we had. Also I would like to thank Siemens AG for gracefully agreeing on disclosure of data in this work. Also, special thanks to my colleagues at Optumatics. Amr Sami, Karim Shalash, Mohammad Bahaa-Eldin, Alaa’ Khalaf and Karim Shehata, the conversations we had were always fruitful and enriching. Hossam Samir, your help with ANSYS ICEM software has saved me precious time and effort. And last but not least, my sincerest gratitude is for Dr. Sherif El-Tahry, Optumatics COO, for his understanding and patience through critical times of this work and for motivating and inspiring me in ways no one else could.

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