Free-Vortex Combustor
A free-vortex combustor is disclosed that generates vortices which: enhance fuel air mixing, recirculate the air, provide cooling for the combustor walls, and provide low emissions and a substantially uniform exit temperature profile. The combustor is provided fuel or fuel and air through a fuel injector which atomizes the fuel. A first air swirler couples to the fuel injector with a prechamber wall abutting the first swirler. A second swirler abuts a downstream end of the prechamber wall. And, a main chamber abuts the second swirler. Each of the first and second swirlers have features that cause the flow to create a vortex in the prechamber and main chamber, respectively. The features creating the swirl are blades or angled orifices. The vortex causes a pressure depression along the centerline and causes backflow along the centerline that improves mixing and improves cooling.
1 . A continuous combustor, comprising:
a fuel injector;
a first air inlet ring abutting the fuel injector on a downstream end of the injector;
a prechamber wall abutting the first air inlet ring;
a second air inlet ring abutting a downstream end of the prechamber wall; and
a main chamber wall abutting the second air inlet ring wherein the first and second air inlet rings each comprise: an inner wall; an outer wall; and a plurality of flow deflectors disposed between the inner and outer rings.
2 . The combustor of claim 1 wherein the flow deflectors comprise at least one of:
blades that are coupled between the inner; and
outer walls and a plurality of angled orifices defined in the air inlet ring.
3 . The combustor of claim 1 wherein:
a downstream portion of the prechamber wall is a conical frustum with a downstream end of the conical frustum having a greater diameter than an upstream end of the conical frustum.
4 . The combustor of claim 3 wherein:
the conical frustum has a plurality of orifices defined therein; and
the plurality of orifices is around a circumference of the conical frustum at a predetermined distance between the upstream end and the downstream end of the conical frustum.
5 . The combustor of claim 1 wherein the main chamber wall comprises three portions:
an upstream portion that comprises a first cylindrical wall;
a downstream portion that comprises a second cylindrical wall of a diameter less than the first cylindrical wall; and
a central portion coupled between the first and second cylindrical walls, the central portion being a conical frustum wall.
6 . The combustor of claim 5 , further comprising: a plurality of orifices defined in the second cylindrical wall.
7 . The combustor of claim 1 , further comprising: a dilution zone wall having a third air inlet ring wherein:
an upstream end of the dilution zone wall abuts a downstream end of the main chamber.
8 . The combustor of claim 7 , further comprising:
a combustor housing in which the prechamber wall, the main chamber wall, and the dilution zone wall are disposed wherein air provided to the combustor flows through a duct formed between an inner surface of the housing and an outer surface of the prechamber wall, the main chamber wall, and the dilution zone wall.
9 . The combustor of claim 1 wherein:
a prechamber is partially defined by the injector and the prechamber wall;
the injector provides fuel into the prechamber at a fuel mass flow rate;
air is provided to the prechamber via the injector at a first air mass flow rate;
air is inducted into the prechamber at a second air mass flow rate;
an actual air-fuel ratio in the prechamber is a sum of the first and second air mass flow rates divided by the fuel mass flow rate; and
the actual air-fuel ratio in the prechamber is less than a stoichiometric air-fuel ratio.
10 . The combustor of claim 9 wherein:
a main chamber is located within the main chamber wall;
air is inducted into the main chamber at a third air mass flow rate;
actual air-fuel ratio in the main chamber is a sum of the first, second, and third air mass flow rates divided by the fuel mass flow rate; and
the actual air-fuel ratio in the main chamber is greater than the stoichiometric air-fuel ratio.
11 . The combustor of claim 1 , further comprising: an ignitor wherein a tip of the injector extends through one of the prechamber wall and the main chamber wall.
12 . The combustor of claim 7 , further comprising: a mechanical compression spring disposed between at least one of the following:
the injector and the first air inlet ring;
the first air inlet ring and the prechamber wall;
the prechamber wall and the second air inlet ring;
the second air inlet ring and the main chamber wall; and
the main chamber wall and the dilution zone wall.
13 . A combustor, comprising:
a fuel injector;
an upstream air inlet ring abutting the fuel injector; and
a prechamber wall abutting the upstream air inlet ring wherein:
an upstream portion of the prechamber wall comprises a first cylindrical wall; and
a downstream portion of the prechamber wall is a first conical frustum with a downstream end of the first conical frustum having a greater diameter than an upstream end of the first conical frustum.
14 . The combustor of claim 13 , further comprising:
a central air inlet ring abutting the downstream portion of the prechamber wall; and
a main chamber wall abutting the central air inlet ring wherein the main chamber wall comprises three portions:
an upstream portion that comprises a second cylindrical wall;
a downstream portion that comprises a third cylindrical wall of a diameter less than the second cylindrical wall; and
a central portion coupled between the second and third cylindrical walls, the central portion being a second conical frustum with the upstream end of the second conical frustum having a diameter substantially equal to a diameter of the second cylindrical wall and the downstream end of the second conical frustum having a diameter substantially equal to the diameter of the third cylindrical wall.
15 . The combustor of claim 13 further comprising:
a first plurality of blades disposed in the first air inlet ring; and
a second plurality of blades disposed in the second air inlet ring.
16 . The combustor of claim 13 , further comprising: a dilution zone having a third air inlet ring wherein:
an upstream end of the dilution zone abuts a downstream end of the main chamber.
17 . The combustor of claim 16 , further comprising:
a housing in which the prechamber, the main chamber, and the dilution zone are disposed wherein air provided to the combustor flows through a duct formed between an inner surface of the housing and an outer surface of the prechamber, the main chamber, and the dilution zone.
18 . The combustor of claim 13 , further comprising:
a compression spring disposed between one of:
the fuel injector and the prechamber; and
the prechamber and the main chamber.
19 . The combustor of claim 13 wherein:
the first conical frustum has a first plurality of orifices defined therein; and
the third cylindrical wall has a second plurality of orifices.
20 . The combustor of claim 13 , further comprising: an ignitor that pierces one of the prechamber wall and the main chamber with a tip of the injector within the combustor.