A swirler apparatus for a combustor, including: primary and secondary swirlers disposed axially adjacent to each other along a swirler centerline; the primary swirler including a plurality of primary swirl vanes arrayed around the swirler centerline; and the secondary swirler including a plurality of secondary swirl vanes arrayed around the swirler centerline, each secondary swirl vane including opposed sides bounded between opposed forward and aft edges and opposed leading and trailing edges; wherein the forward edge is oriented at a first vane angle with respect to a radial direction; wherein the aft edge is oriented at a second vane angle with respect to the radial direction; and wherein the second vane angle is different from the first vane angle.

A swirler apparatus for a combustor, including: primary and secondary swirlers disposed axially adjacent to each other along a swirler centerline; the primary swirler including a plurality of primary swirl vanes arrayed around the swirler centerline; and the secondary swirler including a plurality of secondary swirl vanes arrayed around the swirler centerline, each secondary swirl vane including opposed sides bounded between opposed forward and aft edges and opposed leading and trailing edges; wherein the forward edge is oriented at a first vane angle with respect to a radial direction; wherein the aft edge is oriented at a second vane angle with respect to the radial direction; and wherein the second vane angle is different from the first vane angle.

A flow distribution system for distributing and dividing the flows of at least two separate fluids, the distribution system comprising: a three-dimensional nested structure of at least two fluid transporting fractals comprising at least a first fluid transporting fractal and a second fluid transporting fractal, each fluid transporting fractal having a respective fluid inlet which bifurcates to a plurality of fluid outlets, each fluid transporting fractal being configured to facilitate a flow therethrough independent from a flow in the other fluid transporting fractal, each fluid transporting fractal extending along and about a central axis between fluid inlet and a plurality of fluid outlets; wherein each fluid transporting fractals comprises of a series of recursive bifurcation units assembled in a selected number of stages, each bifurcation unit comprising a Y-shaped bifurcated element which is fluidly connected to two successive bifurcation units, each successive bifurcation unit being rotated relative to the central axis by an angle of between 60 and 120 degrees relative to the previous stage; each fluid transporting fractal is intertwined with the other fluid transporting fractal; each fluid transporting fractal is positioned offset from the other fluid transporting fractal about the central axis and are arranged such that each fluid outlet from one of the fluid transporting fractals is located adjoining a fluid outlet of the other fluid transporting fractal, and each fluid transporting fractal is centered about a flow axis which is laterally inclined from greater than 0 to 20 degrees from the central axis and longitudinally inclined from greater than 0 to 20 degrees from the central axis.

According to an embodiment, a fired heater includes a fuel and combustion air source configured to output fuel and combustion air into a combustion volume, the combustion volume including a combustion volume wall defining a lateral extent separate from an exterior volume. According to an embodiment, the fired heater includes a boiler heater and the combustion volume wall comprises a combustion pipe defining a lateral extent of the combustion volume, the combustion pipe being disposed to separate the combustion volume from a water and steam volume. The fired heater includes a mixing tube aligned to receive the fuel and combustion air from the fuel and combustion air source. The mixing tube may be separated from the combustion volume wall by a separation volume. The fired heater includes a bluff body flame holder aligned to receive a fuel and combustion air mixture from an outlet end of the mixing tube. The bluff body flame holder may be configured to hold a combustion reaction for heating a combustion volume wall. The combustion volume wall may include a combustion pipe. The combustion pipe may be configured to heat the water in the water and steam volume.

According to an embodiment, a fired heater includes a fuel and combustion air source configured to output fuel and combustion air into a combustion volume, the combustion volume including a combustion volume wall defining a lateral extent separate from an exterior volume. According to an embodiment, the fired heater includes a boiler heater and the combustion volume wall comprises a combustion pipe defining a lateral extent of the combustion volume, the combustion pipe being disposed to separate the combustion volume from a water and steam volume. The fired heater includes a mixing tube aligned to receive the fuel and combustion air from the fuel and combustion air source. The mixing tube may be separated from the combustion volume wall by a separation volume. The fired heater includes a bluff body flame holder aligned to receive a fuel and combustion air mixture from an outlet end of the mixing tube. The bluff body flame holder may be configured to hold a combustion reaction for heating a combustion volume wall. The combustion volume wall may include a combustion pipe. The combustion pipe may be configured to heat the water in the water and steam volume.

A system for mixing hydrogen gas and air includes a housing extending from a first end to a second end and defining a mixing chamber. The second end receives the air. A tubular mixer in the mixing chamber extends along a central axis from a first end to a second end. The mixer has an outer surface and an inner surface defining a central passage. The second end is closed by an end wall. The mixer has first fluid directing structure for directing the air and the hydrogen gas radially inward from the mixing chamber to the central passage to form a mixture. A distributor is secured to the first end of the housing and receives the mixture from the first end of the mixer. The distributor includes second fluid directing structure for directing the mixture radially outward to a burner.

A bottom cup cover, a burner and a gas appliance are provided. The bottom cup cover includes a gas intake assembly defining a first gas intake channel, a second gas intake channel, and a connecting channel connecting the first gas intake channel to the second gas intake channel. The second gas intake channel is obliquely arranged relative to the first gas intake channel. The first gas intake channel has a gas inlet. The bottom cup cover defines a first primary air supplement cavity and a second primary air supplement cavity separated from the first primary air supplement cavity. The first gas intake channel is in communication with the first primary air supplement cavity, the second gas intake channel is in communication with the second primary air supplement cavity, and the connecting channel is configured to enable a gas flow to circulate between the first and second primary air supplement cavities.

A bottom cup cover, a burner and a gas appliance are provided. The bottom cup cover includes a gas intake assembly defining a first gas intake channel, a second gas intake channel, and a connecting channel connecting the first gas intake channel to the second gas intake channel. The second gas intake channel is obliquely arranged relative to the first gas intake channel. The first gas intake channel has a gas inlet. The bottom cup cover defines a first primary air supplement cavity and a second primary air supplement cavity separated from the first primary air supplement cavity. The first gas intake channel is in communication with the first primary air supplement cavity, the second gas intake channel is in communication with the second primary air supplement cavity, and the connecting channel is configured to enable a gas flow to circulate between the first and second primary air supplement cavities.

A catalytic burner arrangement is provided including at least a catalytic burner unit with a housing having a reaction chamber in which a catalyst is arranged, wherein the catalyst is adapted to react a fuel, particularly a hydrogen containing fluid, with an oxidant, particularly air, for producing heat, the housing having a fluid inlet for supplying a fluid stream into the housing and a find outlet for exiting a fluid stream from the housing, and the catalytic burner arrangement further includes a mixing unit forming a mixing chamber in which fuel and oxidant are mixed, wherein the mixing device includes a fuel inlet, an oxidant inlet and an fuel-oxidant-mixture outlet, and wherein the fluid inlet of the catalytic burner unit merges with the fuel-oxidant-outlet of the mixing unit for transferring the fuel-oxidant-mixture from the mixing chamber to the reaction chamber of the catalytic burner unit wherein the fuel-oxidant-outlet of the mixing chamber is pipe-shaped and extents into the mixing chamber of the mixing unit, and wherein a length of the pipe-shaped fuel-oxidant-outlet extents over the oxidant inlet and/or the fuel inlet.

A catalytic burner arrangement is provided including at least a catalytic burner unit with a housing having a reaction chamber in which a catalyst is arranged, wherein the catalyst is adapted to react a fuel, particularly a hydrogen containing fluid, with an oxidant, particularly air, for producing heat, the housing having a fluid inlet for supplying a fluid stream into the housing and a find outlet for exiting a fluid stream from the housing, and the catalytic burner arrangement further includes a mixing unit forming a mixing chamber in which fuel and oxidant are mixed, wherein the mixing device includes a fuel inlet, an oxidant inlet and an fuel-oxidant-mixture outlet, and wherein the fluid inlet of the catalytic burner unit merges with the fuel-oxidant-outlet of the mixing unit for transferring the fuel-oxidant-mixture from the mixing chamber to the reaction chamber of the catalytic burner unit wherein the fuel-oxidant-outlet of the mixing chamber is pipe-shaped and extents into the mixing chamber of the mixing unit, and wherein a length of the pipe-shaped fuel-oxidant-outlet extents over the oxidant inlet and/or the fuel inlet.