Combustion systems

1. A combustion system comprising:

an annular combustor dome comprising an inner dome ring and an outer dome ring;

a plurality of circumferentially spaced apart nozzles;

a plurality of tiles to fluidly separate a downstream side of the combustor dome from an upstream side of the combustor dome,

wherein each tile is mounted around a respective one of the nozzles

wherein each tile is spaced apart from the respective one of the nozzles in an axial direction between the upstream and downstream sides of the combustor dome to define an outer air circuit between the tile and the respective one of the nozzles;

wherein each nozzle includes a radial swirler on the upstream side of the combustor dome in fluid communication with a nozzle outlet on the downstream side of the combustor dome, wherein an inner air circuit is defined from the radial swirler to the nozzle outlet;

wherein struts supporting each nozzle in the combustor dome modestly obstruct flow only to the outer air circuit and the inner air circuit is unobstructed by the struts,

wherein the struts are an integral part of, and extend radially from, the inner dome ring and the outer dome ring of the combustor dome to each respective nozzle; and

wherein the tiles are confined axially by an outer bayonet ring proximate a radially outer perimeter defined by the tiles, and by an inner bayonet ring proximate a radially inner perimeter defined by the tiles, wherein each of the bayonet rings is interlocked with bayonet features in a respective one of the inner dome ring and outer dome ring.

2. A combustion system as recited in claim 1 , wherein each nozzle includes a downstream insulation shell with a standoff extending in a downstream direction from the nozzle, wherein the standoff spaces the tile from the nozzle to maintain space for the outer air circuit.

3. A combustion system as recited in claim 2 , wherein each tile includes a radial slot that receives the standoff.

4. A combustion system as recited in claim 1 , wherein each tile defines a converging frustoconical surface that defines a portion of the outer air circuit.

5. A combustion system as recited in claim 1 , wherein the inner and outer air circuits are configured to issue 40% to 50% of airflow passing through the combustor dome through the inner air circuit, and to issue 50% to 60% of the airflow through the outer air circuit, wherein the total airflow of the inner and outer airflow circuits does not exceed 100%.

6. A combustion system as recited in claim 1 , wherein a channel forming the inlet of the outer air circuit is proximate an upstream surface of the tile for cooling of the tile by airflow passing into the outer air circuit.

7. A combustion system as recited in claim 1 , wherein each tile includes a radial edge with a radially extending groove defined therein, wherein each tile includes a radial edge with a radially extending tongue thereon, and wherein each tile engages circumferentially adjacent neighbor tiles wherein the tongues are engaged in the grooves.

8. A combustor system as recited in claim 1 , wherein each tile includes a ceramic matrix composite (CMC) material.

9. A combustor for a gas turbine engine comprising:

an inner combustor wall;

an outer combustor wall radially outboard of the inner combustor wall,

wherein the inner and outer combustor walls define a combustion space therebetween with an upstream inlet and a downstream outlet;

and a combustor dome connecting between inner and outer combustor walls at the upstream inlet of the combustion space,

the combustor dome comprising an inner dome ring and an outer dome ring;

a plurality of circumferentially spaced apart nozzles;

a plurality of tiles to fluidly separate a downstream side of the combustor dome from an upstream side of the combustor dome,

wherein each tile is mounted around a respective one of the nozzles,

wherein each tile is spaced apart from the respective one of the nozzles in an axial direction between the upstream and downstream sides of the combustor dome to define an outer air circuit between the tile and the respective one of the nozzles;

wherein each nozzle includes a radial swirler on the upstream side of the combustor dome in fluid communication with a nozzle outlet on the downstream side of the combustor dome, wherein an inner air circuit is defined from the radial swirler to the nozzle outlet;

wherein struts supporting each nozzle in the combustor dome modestly obstruct flow only to the outer air circuit and the inner air circuit is obstructed by the struts,

wherein the struts are an integral part of, and extend radially from, the inner dome ring and the outer dome ring of the combustor dome to each respective nozzle; and

wherein the tiles are confined axially by an outer bayonet ring proximate a radially outer perimeter defined by the tiles, and by an inner bayonet ring proximate a radially inner perimeter defined by the tiles, wherein each of the bayonet rings is interlocked with bayonet features in a respective one of the inner dome ring and outer dome ring.

10. A combustor as recited in claim 9 , wherein the outer bayonet ring slidingly supports a cold side combustor liner of the outer combustor wall, and wherein the inner bayonet ring slidingly supports a cold side combustor liner of the inner combustor wall.

11. A combustor as recited in claim 9 , wherein the outer bayonet ring forms a cold side combustor liner of the outer combustor wall, and wherein the inner bayonet ring forms a cold side combustor liner of the inner combustor wall.