A method of issuing a spray cone from a nozzle includes modulating flow to two separate first and second fluid circuits, each connected to a common injection point orifice to vary spray angle on a substantially hollow spray cone over time to create a full spray cone. Modulating can include controlling first and second flow modulators, connected to the first and second fluid circuits, respectively, to coordinate oscillating flow rate modulation of both of the first and second fluid circuits. Controlling can include controlling the oscillating flow rate modulation for the first flow modulator to be out of phase with, to be in antiphase with, to be vertically shifted in magnitude relative to, and/or to have an amplitude that is equal to that of the second flow modulator.

An alternative-fuel gas orifice, a gas furnace configured to employ the same and a method of designing a gas orifice. In one embodiment, the gas orifice includes: (1) a body having an aperture extending therethrough and including: (1a) a metering neck having a cross-sectional area such that a given flow rate of a gas is established when the gas is delivered to the gas orifice at a given alternative-fuel delivery pressure and (1b) a diffuser having a cross-sectional area larger than the cross-sectional area of the metering neck and a length such that the gas achieves a substantially laminar flow before exiting the diffuser.

An alternative-fuel gas orifice, a gas furnace configured to employ the same and a method of designing a gas orifice. In one embodiment, the gas orifice includes: (1) a body having an aperture extending therethrough and including: (1a) a metering neck having a cross-sectional area such that a given flow rate of a gas is established when the gas is delivered to the gas orifice at a given alternative-fuel delivery pressure and (1b) a diffuser having a cross-sectional area larger than the cross-sectional area of the metering neck and a length such that the gas achieves a substantially laminar flow before exiting the diffuser.

A fuel injector for a gas turbine engine combustor is provided that includes a swirler, a mounting stage, and a distributor. The swirler has a shaft, a collar, a throat section, and first and second axial ends. The throat section includes an inner radial surface that defines a central passage that extends between the swirler inner bore and the collar. The collar includes a plurality of apertures extending therethrough disposed radially outside of the central passage. The mounting stage is disposed in the inner bore, and has an annular flange, a central hub, and at least one strut. The distributor has a stem attached to a head. The stem has a distal end opposite the head portion engaged with the central hub. The head portion has an end surface and a side surface. The distributor is selectively positionable relative to the throat section.

A fuel nozzle apparatus can include a nozzle that functions with two or more modes of operation with respect to a group of fuels, and an air shroud fixed over the nozzle. The air shroud blocks air through the nozzle or allows air through the nozzle in a predefined pattern. When a position of the air shroud is varied, the amount of the air and the location of the air into the nozzle is changed to facilitate the two or more modes of operation with respect to the group of fuels.