Analytical study of superadiabatic small-scale combustors with a two-step chain-branching chemistry model: Lean burning below the flammability limit

Abstract

A study of combustion in small-scale superadiabatic burners with a counter-flow heat exchange segment is presented for a simple two-step chain-branching chemistry model. The work is focused on the possibility of burning below the flammability limit. The investigation is carried out in the high activation energy limit on the basis of analytical solutions. The existence of multiple steady-state regimes is demonstrated and their stability properties are investigated. These analytical results are finally compared with the results of numerical simulations carried out for finite activation energies.