CFD investigation of a Stirling engine f exi-fuel burner based on MILD combustion

Paper in proceeding, 2015

This paper presents the comparison of results from tests and 3D CFD combustion simulations based on both RANS and hybrid URANS/LES (SAS-SST model) turbulence models applied to an industrial Stirling engine combustion chamber at atmospheric pressure. Both natural gas and landf ll gas mixture were simulated. The combustor is designed to operate in the MILD combustion mode which is characterized by low f ame temperatures and low NOX emissions. The kinetics for the landf ll gas was represented by a new optimized 4-step global mechanism, named AAT4NR, which was optimized for the present landf ll mixture. The new mechanism is developed using well-established optimization tools, where the coeff cients of the 4-step global chemistry are determined from a set of reference detailed chemistry solutions. A good agreement with measurements is found concerning major emissions, temperatures and NOX-levels.