Laminar burning velocity of hybrid methane-iron-air flames

As widely acknowledged, it is mandatory to decarbonize our energy system. A low-cost opportunity to achieve this is with high energy density metal carriers. Renewable energy can be used to reduce metal oxides to metal. This metal can be stored under ambient conditions in the form of a powder and be combusted (=oxidised) whenever energy is needed, providing fully renewable heat. In this work, micron sized iron powder is considered as metal energy carrier and the effect of iron powder on the adiabatic burning velocity of methane-air flames is investigated for different mixtures. To do so the Heat Flux (HF) method is used to stabilize hybrid methane-iron-air flames on a perforated plate on which is heated at the rim. Thermocouples are connected at different distances from the center of the plate. This way, the change in adiabatic burning velocity of flames can be found by measuring the temperature gradient over the burner plate for different mixtures and gas velocities. Via a loadcell connected to a dispersion system, the iron powder mass flow is tracked. By combining the data from the loadcell with the thermocouples data the effect different powder loading for various gas mixtures on the burning velocity can be extracted. The challenges here are to supply the flame with a continuous and accurate mass flow of iron particles while also taking into account the dynamics of the created aerosol.