Numerical investigation of the influence of the fuel on the performance of a laboratory combustor.

July 9, 2020

In this work, numerical simulations were performed to study the fuel flexibility of a small-scale combustor operating in the flameless combustion mode. The combustor geometrical characteristics and the operating conditions, such as thermal power and equivalence ratio (φ), were kept constant for all fuels studied. The studied fuels were: methane, propane, acetylene, ethanol, biogas, syngas, hydrogen and mixtures of CH4/H2, CH4/NH3 and H2/NH3. In the CH4/NH3 and H2/NH3 mixtures, the influence of NH3 concentration and the equivalence ratio (φ) to obtain this combustion regime were also studied. The numerical model applied was validated through the numerical and experimental comparison of the temperature and species concentration fields obtained from the methane flameless combustion. The numerical results show that for a preheated air temperature of 900 K and φ = 0.5, flameless combustion can be obtained for all fuels except acetylene, syngas and hydrogen. These three fuels have a non-uniform temperature field combined with rapid oxygen and fuel consumption, which suggests the presence of a flame front. In the CH4/NH3 and H2/NH3 mixtures, the flameless combustion can be established for the two NH3 concentrations studied and also for φ ≤ 1. In the fuel-rich condition (φ = 1.2), the numerical results suggest the presence of a flame front for both mixtures.

Authors in the community:

• 

  P

  Pedro Daniel Canuto Rijo

  ist181029

Supervisors of this institution:

• 

  P

  Pedro Jorge Martins Coelho

  ist12272

mechanical-engineering - Mechanical engineering

por - Portuguese

Instituto Superior Técnico