A combustor including a first perforated layer including a first opening having a first diameter, wherein the first opening is configured to receive a flow of fluid including a fuel and air mixture; and impart a first rotational instability to the flow of fluid that is dependent on the first diameter; and a second perforated layer surrounding a combustion area, wherein the second perforated later includes a second opening having a second diameter, and wherein the second layer is located between the first layer and the combustion area.

A cylindrical gas premix burner comprises a cylindrical burner deck onto which the flames are stabilized when the burner is in use; a mixing chamber inside the cylindrical burner deck; an inlet device mounted perpendicularly to the axial direction of the cylindrical burner deck for the supply of premix gas into the mixing chamber; and an end cap closing off the mixing chamber at the side opposite to the side where the inlet device is provided. The inlet device comprises a perforated metal plate. The perforations in the perforated metal plate are provided for the supply of premix gas into the mixing chamber. The perforated metal plate is dome shaped; such that perforations in the perforated metal plate are located at different height levels from the base of the cylindrical burner deck.

According to an embodiment, a combustion system is provided, which includes a nozzle configured to emit a diverging fuel flow, a flame holder positioned in the path of the fuel flow and that includes a plurality of apertures extending therethrough, and a preheat mechanism configured to heat the flame to a temperature exceeding a startup temperature threshold.

A combustor including a first perforated layer including a first opening having a first diameter, wherein the first opening is configured to receive a flow of fluid including a fuel and air mixture; and impart a first rotational instability to the flow of fluid that is dependent on the first diameter; and a second perforated layer surrounding a combustion area, wherein the second perforated later includes a second opening having a second diameter, and wherein the second layer is located between the first layer and the combustion area.

A premixed gas heating system comprises: a fan assembly (2) configured to supply a premixed air-gas flow required for combustion, wherein a combustible gas of the premixed air-gas flow contains at least 20% by volume of hydrogen; a burner (5) comprising a plurality of holes, wherein the plurality of holes provides a free passage area defined as an area that allows the outflow of the premixed air-gas flow from an area upstream of the burner (5) to an area where flames of combustion are generated; a load controller, configured to regulate an output load of the burner (5) such that the heating system modulates between a minimum load and a maximum load, wherein a ratio between the minimum load and the maximum load is at least 4, wherein the minimum load of the heating system is set such that a combustion index, defined as the ratio between the minimum load and the free passage area of the burner, is between 4 E06 and 6 E07.

According to an embodiment, a combustion system is provided, which includes a nozzle configured to emit a diverging fuel flow, a flame holder positioned in the path of the fuel flow and that includes a plurality of apertures extending therethrough, and a preheat mechanism configured to heat the flame to a temperature exceeding a startup temperature threshold.

A burner apparatus for burning a gas and air mixture may include a burner wall. The burner wall may have a plurality of ridges and a plurality of grooves. Each groove may be defined between adjacent ridges. Each groove may also include a pair of slopes. Each slope may have an area of permeability having openings defined therein from which flames can project. Each ridge may define an area of reduced permeability relative to the areas of permeability of the slopes.

The burner (100) comprises a cylindrical porous substrate (110); and an end cap (130) at a first end of the cylindrical porous substrate (110). The cylindrical porous substrate (110) is provided for flow of a premix of combustible gas and air from the outside of the cylindrical porous substrate (110) through the pores of the cylindrical porous substrate (110) to an interior cavity (140), for the combustible gas to be combusted on the inner surface of the cylindrical porous substrate (110) thereby generating hot gas. The burner has an opening (182) at the second end of the cylindrical porous substrate (110) to exit the hot flue gas out of the interior cavity (140). The cylindrical porous substrate (110) has a higher permeability section (170), located at the opening (182) at the second end. The higher permeability section (170) has a lower resistance to gas flow than other sections of the cylindrical porous substrate (110).

A combustion system such as a furnace or boiler includes a perforated reaction holder configured to hold a combustion reaction that produces very low oxides of nitrogen (NOx).

A combustion system outputs fuel gas from a plurality of fuel ejectors toward a forward end of a burner wall and preheats a perforated flame holder by sustaining combustion reaction of the fuel gas at combustion zone between the burner wall and a perforated flame holder. The combustion system then outputs fuel gas from the fuel ejectors onto the perforated flame holder and sustains a combustion reaction of the fuel gas within the perforated flame holder.