Stable pre-mixer for lean burn composition

A fuel injection apparatus, comprising:

• a longitudinally extending housing having an upstream fuel inlet end and a downstream fuel outlet end;
• a liquid fuel inlet to a plurality of liquid fuel spray devices in the housing, said liquid fuel spray devices supported in the housing in an annular arrangement to dispense liquid fuel in sprays in the downstream direction through the housing;
• a gaseous fuel inlet to a plurality of gaseous fuel dispensing devices, said gaseous fuel dispensing devices in the housing also supported in the housing in an annular arrangement to dispense gaseous fuel in streams in the downstream direction through the housing, the gaseous fuel dispensing devices located in alternating, circumferentially-spaced relation with the liquid fuel spray devices, and said plurality of gaseous fuel dispensing devices including a series of gaseous fuel dispensing devices arranged in radial spokes between each of the liquid fuel spray devices;
• an air inlet to an annular flow passage in the housing surrounding the liquid fuel spray devices and the gaseous fuel spray devices to direct air in a cylindrical flow downstream in the housing;
• and
• a radial inflow air swirler stage in the housing, downstream from the liquid fuel spray devices and the gaseous fuel spray devices, said radial inflow air swirler stage directing air radially inward in a swirling motion to cause fuel and air to swirl and thoroughly mix in the housing.

A fuel injection apparatus, comprising:

• a longitudinally extending housing having an upstream fuel inlet end and a downstream fuel outlet end;
• a liquid fuel inlet passage to a plurality of liquid fuel spray devices in the housing, said liquid fuel spray devices supported in an annular arrangement in the housing to dispense liquid fuel in a plurality of sprays in the downstream direction through the housing;
• an air inlet passage to an annular flow passage in the housing surrounding at least one of the liquid fuel spray devices to direct air in a cylindrical flow downstream around the liquid fuel;
• and
• a radial inflow swirler stage in the housing spaced downstream from the liquid fuel spray devices, said radial inflow swirler stage including a pair of inflow swirlers spaced longitudinally from each other, each of which directs air radially inward in a swirling motion at longitudinally-spaced locations in the housing to cause the fuel sprays to swirl and thoroughly mix with air in the housing.

A combustion system including a combustion chamber and a fuel injection apparatus, said fuel injection apparatus including:

• a longitudinally extending injector housing having an upstream fuel inlet end and a downstream fuel outlet end, the downstream fuel outlet end in fluid communication with the combustion chamber;
• a liquid fuel inlet passage to a plurality of liquid fuel spray devices in the housing said liquid fuel spray devices being supported in an annular arrangement in the housing to dispense liquid fuel in a plurality of sprays in the downstream direction through the housing;
• an air inlet passage to an annular flow passage in the housing surrounding at least one of the liquid fuel spray devices to direct air in a cylindrical flow downstream around the liquid fuel;
• and
• a radial inflow swirler stage in the housing spaced downstream from the liquid fuel spray devices, said radial inflow swirler stage including a plurality of inflow swirlers spaced longitudinally from each other, each of which directs air radially inward in a swirling motion at longitudinally-spaced locations in the housing to cause the fuel sprays to swirl and thoroughly mix with air in the housing before passing into the combustion chamber.

A method for premixing liquid fuel and air within an injector before passing the mixture into a combustion chamber for combustion, comprising the steps of:

• providing a longitudinally extending injector housing having an upstream fuel inlet end and a downstream fuel outlet end, the downstream fuel outlet end in fluid communication with the combustion chamber;
• supplying liquid fuel to a plurality of liquid fuel spray devices supported in an annular arrangement in the housing and spraying the liquid fuel in a plurality of sprays in the downstream direction through the housing;
• supplying air to an annular flow passage surrounding the liquid fuel spray devices and dispensing the air in a cylindrical flow downstream around the liquid fuel sprays;
• and
• supplying air to first and second radial inflow swirlers in the housing, said first and second radial inflow swirlers spaced longitudinally apart from one another downstream from the liquid fuel spray devices, and directing the air radially inward in a swirling motion at longitudinally-spaced locations in the housing to cause the liquid fuel and air to swirl and thoroughly mix within the housing prior to being provided to the combustor.