Numerical Investigation of High Pressure CO₂-Diluted Combustion Using a Flamelet-based Approach

ABSTRACT

Direct-fired oxy-fuel combustion as a heat source is utilized in supercritical carbon dioxide (sCO₂) power cycles, such as the Allam cycle, which has shown promise in delivering higher efficiencies while achieving the complete capture of combustion products in future generation carbon-neutral power plants. The design of dedicated burners for such cycles is key in determining their overall efficiency and viability. We present a series of numerical simulations on a prototype burner, currently in development, operating in an essentially non-premixed regime with a high pressure gaseous fuel, burning in the presence of a hot oxidant flow containing a mixture of recycled CO₂ and pure oxygen. Simulations rely on a turbulent combustion model based on a simplified approach for diluted steady laminar flamelets. We investigate the effect of the degree of dilution as well as pressure on the flame structure, revealing a concurrent change in stoichiometric mixture fraction and quenching scalar dissipation. We also assess the effect of injector recess and of swirl in the oxidizer stream.

KEYWORDS:

• Supercritical combustion
• oxy-fuel combustion
• Allam cycle
• supercritical CO₂
• turbulent combustion

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Published as part of the Special Issue on Fundamental Understanding and Modeling of High Pressure Turbulent Premixed Combustion with Guest Editors M. Klein, M. Pfitzner, N. Chakraborty, and F. Creta

Additional information

Funding

The present study has been supported by Italian Ministry of Education, University and Research (MIUR) and KAUST [OSR-2019-CCF-1975-35] Subaward Agreement.