Comparison of LES techniques using a simplified model problem for non-premixed turbulent combustion

Master thesis (2023)

Authors

L.A. Klaessen Aerospace Engineering

Contributors

S.J. Hulshoff Aerodynamics - Aerospace Engineering (supervisor 1)
M. Kotsonis Aerodynamics - Aerospace Engineering (supervisor 2)
I. Langella Flight Performance and Propulsion - Aerospace Engineering (supervisor 2)
Faculty
Aerospace Engineering
Copyright: © 2023 Alexander Klaessen
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Published Date

11-10-2023

Language

English

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Faculty

Aerospace Engineering

Abstract

There is a need to examine the potential of alternative methods such as Variational Multiscale Method (VMM) for the ability to improve the efficiency of combustion simulations. However the computational expense of a LES run of a 3D turbulent non-premixed combustion problem is high due to the large variety of length and time scales in turbulent non-premixed combustion. Secondly, VMM is a sophisticated model and the models used to simulate turbulent non-premixed combustion are complex. And finally, the results of a full 3D turbulent non-premixed combustion simulation are difficult to interpret due to their complexity. Therefore the objectives as follows: Firstly to define a simplified model problem which has the important aspects of turbulent non-premixed combustion for comparing numerical methods. Secondly, to propose and to investigate the potential of a framework based on VMM formulation for non-premixed combustion computations. The results of the simplified model problem in a VMM framework are compared to the results when using a standard Smagorinsky model. Results show that in general the VMM model with the dynamic subscale assumption outperforms the Smagorinsky model when looking at the mean and RMS value of the velocity, mixture fraction and progress variable.