Application of the Lagrangian CMC method in elliptic bluff body and swirl flames

Abstract

The Lagrangian CMC method was implemented in the open source programme OpenFOAM and applied to turbulent nonpremixed bluff body and swirl flames. Lagrangian CMC is more efficient than Eulerian CMC with the number of Lagrangian flame groups much less than the number of computational cells for Eulerian CMC equations in general. It is based on the conditional flame structure depending on the residence time of the fuel of fixed Lagrangian identity from the nozzle. According to sensitivity study the injected fuel was divided into ten flame groups according to the injection sequence with the resulting conditional profiles between those by ISR and Eulerian CMC. Minor deviation from Eulerian CMC was attributed to the flame structure that is difficult to be characterised by the residence time only in elliptic recirculating flows of the bluff body and swirl flames. The Eulerian and Lagrangian CMC showed the same trend of deviation from measurements for conditional temperature, H₂O, OH, CO and H₂ mass fractions. The significant deviation of H₂ was due to uncertainty in the reaction chemistry, as observed in the previous works based on other reaction mechanisms for methane and methanol.

Keywords:

• turbulent nonpremixed combustion
• bluff body flame
• swirl flame
• conditional moment closure (CMC)
• Lagrangian CMC

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Gwang Goo Lee http://orcid.org/0000-0002-4466-2896

Additional information

Funding

Present work was carried out with the support by the Space Core Technology Research Grants (2017M1A3A3A03015996) of the National Research Foundation (NRF) of Korea, funded by the Ministry of Science, ICT (MSIT) of the Korean Government.