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The University of British Columbia

Okanagan campus

Combustion for Propulsion and Power Laboratory

Turbulent combustion (hydrogen-enriched flames)

Development of current and future generation of gas turbine engine combustors requires understanding related to the internal structure of turbulent premixed flames. Specifically, information related to the internal flame structure allows for development of accurate burning rate models. Below, we show how turbulent eddies penetrate into the flame structure.

  • Mohammadnejad, S., An, Q., Vena, P., Yun, S., and Kheirkhah, S. (2021). "Contributions of flame thickening and extinctions to a heat release rate marker of intensely turbulent premixed hydrogen-enriched methane-air flames", Combustion and Flame (accepted).

  • Mohammadnejad, S., An, Q., Vena, P., Yun, S., and Kheirkhah, S. (2020). "Thick reaction zones in non-flamelet turbulent premixed combustion", Combustion and Flame, 222, 285-304.

  • Mohammadnejad, S., Vena, P., Yun, S., and Kheirkhah, S. (2019). "Internal structure of hydrogen-enriched methane-air turbulent premixed flames: Flamelet and non-flamelet behavior", Combustion and Flame, 208, 139-157.

Ignition, flame development, and thermoacoustics

Achieving a smooth start and transition to steady operation is challenging for several power generation engineering equipment. In this study, we characterize flame development at early stages of combustion inside a small scale power generator combustor using synchronized high speed flame chemiluminescence and pressure measurements.

Thermoacoustics 

(heat release and pressure) oscillations often arise in energy-related equipment, for example gas turbine engines and power generators. In-phase heat release and pressure oscillations result in a positive net energy transfer to the engines/power generators. This causes resonance, and, in extreme cases, leads to system thermal and mechanical fatigue.

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The figure on the right hand side illustrates the thermoacoustic oscillations characteristics during transient operation of a small-scale power generator. For more information, please check out the related articles.

spectrogram.jpg

  • Heydarlaki, R., Kostka, P., Aitchison, W., and Kheirkhah, S. (2021). "Competing contributions of  structural, acoustic, and intrinsic modes to thermoaoustic oscillations  ", Combustion Science and Technology (accepted).

  • Mollahoseini, Z., Heydarlaki, R., Kostka, P., Aitchison, W., and Kheirkhah, S. (2020). "Flame development characteristics inside a reverse-flow combustor at early stages of combustion", Experimental Thermal and Fluid Science, 110254.

  • Heydarlaki, R., Kostka, P., Aitchison, W., and Kheirkhah S. (2019) "Influences of initial and transient combustor wall-temperature on thermoacoustic oscillations of a small-scale power generator", Experimental Thermal and Fluid Science, 109, 109856

Novel fuel-air injector concepts

Next generation of gas turbine engines will operate under the mode of hydrogen-enriched turbulent premixed combustion. Stratification and injection architecture both influence the topology and the burning rate of hydrogen-enriched flames. Figure below summarizes effect of injector design on the flame topology. More updates to follow...

  • Mohammadnejad S., Saca, L., Heydarlaki R., An Q., Vena P., Yun S., Versailles P., Bourque G., and Kheirkhah, S. (2021). "Effect of fuel stratification on OH and CH2O PLIF multiplication of turbulent hydrogen-enriched flames", Flow, Turbulence and Combustion (accepted).

Doped droplet combustion

Carbon-based nanomaterial can be used to boost combustion through several processes such as micro-explosions. Our newly developed setup and measurements are shown below. More updates to follow...

Supersonic ejectors

Supersonic ejectors are used  for several engineering applications including material transport and aerospace propulsion. With the CFD lab at UBC Okanagan, we are testing these ejectors and developing understanding related to how the ejector performance, such as pressure oscillations and entrainment ratio, can be improved/controlled. Below are some spectral analysis of the ejector wall pressure oscillations. More to follow...

Dynamics of non-reacting sprays

Non-reacting sprays are relevant to many engineering applications and health-related flows. More to follow...

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