In the realm of energy and combustion research, a team of scientists from the University of California, San Diego, led by Professor William A. Sirignano, has made significant strides in understanding combustion within turbine stators. The researchers, Sylvain L. Walsh, Yalu Zhu, Feng Liu, and William A. Sirignano, have published their findings in the Journal of Engineering for Gas Turbines and Power, a prestigious publication in the field of energy and power generation.
The study focuses on the numerical investigation of combustion within a two-dimensional turbine stator passage, a critical component in gas turbines. The researchers employed a Reynolds-Averaged Navier-Stokes framework coupled with a novel flamelet model. This model uniquely links resolved-scale turbulence quantities with subgrid flamelet dynamics through the local turbulent kinetic energy dissipation rate, denoted as ε. This approach allows for a more accurate determination of the flamelet inflow strain rate, a crucial factor in combustion processes.
One of the standout aspects of this research is the consideration of JP-5, a practical fuel, in a turbine stator passage for the first time. The team achieved this by solving transport equations for 14 major species on the resolved scale, while chemical source terms were obtained from precomputed flamelet libraries based on the HyChem A3 mechanism. This mechanism comprises 119 species and 841 elementary reactions, providing a comprehensive understanding of the combustion process.
The performance of the model was assessed against methane combustion using both a one-step kinetics model and an ε-based flamelet formulation employing a 13-species skeletal mechanism. The ε-based formulation predicted lower peak flame temperatures due to dissociation effects and approximately 50% lower net chemical energy addition per unit mass compared with the one-step model. This difference is attributed to flame stand-off and downstream strain-rate-induced quenching.
For JP-5, the simulations captured combined endothermic pyrolysis and exothermic oxidation processes, leading to vertically displaced reaction zones, increased near-wall temperatures, and larger resolved-scale reaction regions. These findings are due to the higher flamelet flammability limit of JP-5 relative to methane.
The practical applications of this research are significant for the energy sector, particularly in the design and optimization of gas turbines. By understanding the combustion dynamics within turbine stators, engineers can improve the efficiency and performance of these critical components. This, in turn, can lead to more efficient power generation and reduced emissions, contributing to a more sustainable energy future.
The research was published in the Journal of Engineering for Gas Turbines and Power, a leading publication in the field of energy and power generation. The findings represent a significant advancement in the understanding of combustion processes within turbine stators, with practical implications for the energy industry.
This article is based on research available at arXiv.