Project Director

Ranjan, Reetesh

Department Examiner

Wigal, Cecelia; Margraves, Charles H.

Department

Dept. of Mechanical Engineering

Publisher

University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)

Abstract

This thesis presents an uncertainty quantification (UQ) study of turbulent premixed flames, focusing on the impact of uncertainties in operating conditions on the normalized consumption speed. Namely, temperature, pressure, and equivalence ratio are the operating conditions that are under study. Due to significant computational demands associated with direct MC methods for UQ, surrogate modeling techniques including Polynomial Chaos Expansion (PCE), Stochastic Collocation (SC), and Gaussian Process (GP) are evaluated based on efficiency and accuracy. Through this study, PCE is identified as the optimal surrogate model due to its accuracy and significantly reduced computational costs. PCE is subsequently applied to investigate how variability in temperature, pressure, and equivalence ratio affect the normalized consumption speed of turbulent premixed flames. Results highlight that the normalized consumption speed has considerable sensitivity to variations in temperature and equivalence ratio, with nonlinear behaviors shown through probability density functions and statistical metrics. Pressure variations had only small impacts on the normalized consumption speed of turbulent premixed flames. The framework employed in this study can be applied to other complex combustion simulations.

Acknowledgments

I would like to express my gratitude to my advisor, Dr. Reetesh Ranjan, for his guidance and support throughout this thesis. His mentorship has contributed greatly to my growth as a student. I am greatly appreciative of my thesis committee members, Dr. Cecelia Wigal and Dr. Charles Margraves, for their encouragement and guidance through this project and my academic career. Additionally, I would like to acknowledge the University of Tennessee at Chattanooga and the UTC Research Institute for providing the computational resources used for this research.

Degree

B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.

Date

5-2025

Subject

Combustion--Mathematical models; Computational fluid dynamics; Flame stability; Turbulence; Uncertainty (Information theory)--Mathematical models

Keyword

uncertainty quantification; combustion; premix flames; Dakota; AVF-LESLIE

Discipline

Heat Transfer, Combustion

Document Type

Theses

Extent

ix, 54 leaves

DCMI Type

Text

Language

English

Rights

http://rightsstatements.org/vocab/InC/1.0/

License

http://creativecommons.org/licenses/by/4.0/

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