Date of Award

Fall 2026

Abstract

A 9-burner annular micro gas turbine combustor designed by Brayton Energy for use as a range extender in a hybrid vehicle is modeled in OpenFOAM (V2412). The primary goal of this work is to obtain a reliable and computationally efficient OpenFOAM model for future analysis by Brayton Energy. Two primary simplifications are considered: a single-burner model and an artificial heat addition model.

The single-burner (40°) sector utilized cyclic (periodic) boundary conditions and the inherent symmetry of the combustor to reduce the simulation domain and hence decrease simulation time. The single sector was compared against a three-burner (120°) sector to assess if the flame-flame interactions affect the primary flow. The single burner reduced the simulation time by ~2.5× while accurately capturing primary central recirculation zone (CRZ) dynamics and predicting the combustor pattern factor within 9% of the three-burner benchmark (0.105 vs. 0.115).

Second, an artificial heat addition model consisting of a fixed heat source and a 2200\ K temperature cap in a steady-state solver (rhoSimpleFoam) was compared against an eddy-dissipation concept (EDC) chemical reaction model (reactingFoam). While the artificial heat addition method reduced computation time by several orders of magnitude, the heat addition caused non-physical thermal accumulation in the CRZ. This weakened the core pressure gradient, altered CRZ topology, and severely degraded exit parameter accuracy, overpredicting the pattern factor by 91% (0.21 vs. 0.11).

The results demonstrate that a single-burner sector can provides a robust, computationally efficient tool for combustor analysis in OpenFOAM while the artificial heat addition proved to be an unreliable substitute for chemical combustion models.

Document Type

Master's Thesis

First Advisor

Ivaylo Nedyalkov

Second Advisor

Christopher White

Third Advisor

Jason Simon

Department or Program

Mechanical Engineering

Degree Name

Master of Science

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