Apparatus and method for air extraction at a gas turbine engine combustor
An air extraction port at a combustor of a gas turbine engine includes a port inlet at a combustor case of the combustor having an inlet area, a port outlet having a final area, and a fluid passage extending from the port inlet to the port outlet to convey an airflow, the port inlet sized and configured to extract the airflow from the combustor case at the same nominal upstream Mach number with a tolerance of +/−0.05.
1. An air extraction port at a combustor of a gas turbine engine comprising:
a port inlet at a combustor case of the combustor, the port inlet having an inlet area;
a port outlet having a final area; and
a fluid passage extending from the port inlet to the port outlet to convey an airflow, the port inlet sized and configured to extract the airflow from the combustor case at a nominal local Mach number;
wherein the inlet area is greater than the final area; and
wherein a contraction from the inlet area to the final area occurs over a passage length proportional to an inlet hydraulic diameter of the port inlet, wherein a ratio of the passage length to the inlet hydraulic diameter is equal to or greater than 4.
2. The air extraction port of claim 1 , wherein a ratio of the inlet area to the final area is greater than 1.0 and less than or equal to 1.6.
3. The air extraction port of claim 1 , wherein the ratio of the passage length to the inlet hydraulic diameter is between 4 and 8.
4. The air extraction port of claim 1 , further comprising one or more bends in the fluid passage between the port inlet and the port outlet.
5. The air extraction port of claim 4 , wherein each bend has a bend radius between one and two times an inlet hydraulic diameter of the port inlet.
6. A combustor for a gas turbine engine comprising:
a combustor case; and
a combustor liner disposed in the combustor case, radially offset from the combustor case to define an airflow pathway between the combustor case and the combustor liner; and
an air extraction port including:
a port inlet at the combustor case of the combustor, the port inlet having an inlet area;
a port outlet having a final area; and
a fluid passage extending from the port inlet to the port outlet to convey an airflow, the port inlet sized and configured to extract the airflow from the combustor case at a nominal local Mach number;
wherein the inlet area is greater than the final area; and
wherein a contraction from the inlet area to the final area occurs over a passage length proportional to an inlet hydraulic diameter of the port inlet, wherein a ratio of the passage length to the inlet hydraulic diameter is equal to or greater than 4.
7. The combustor of claim 6 , wherein a ratio of the inlet area to the final area is greater than 1.0 and less than or equal to 1.6.
8. The combustor of claim 6 , wherein the ratio of the passage length to the inlet hydraulic diameter is between 4 and 8.
9. The combustor of claim 6 , further comprising one or more bends in the fluid passage between the port inlet and the port outlet.
10. The combustor of claim 9 , wherein each bend has a bend radius between one and two times an inlet hydraulic diameter of the port inlet.
11. A gas turbine engine comprising:
a turbine; and
a combustor operably connected to the turbine, the combustor driving the turbine via combustion products of the combustor, the combustor including:
a combustor case; and
a combustor liner disposed in the combustor case, radially offset from the combustor case to define an airflow pathway between the combustor case and the combustor liner; and
an air extraction port including:
a port inlet at the combustor case of the combustor, the port inlet having an inlet area;
a port outlet having a final area; and
a fluid passage extending from the port inlet to the port outlet to convey an airflow, the port inlet sized and configured to extract the airflow from the combustor case at a nominal local Mach number, the airflow utilized to cool one or more turbine components;
wherein a ratio of the inlet area to the final area is greater than 1.0 and less than or equal to 1.6; and
wherein a contraction from the inlet area to the final area occurs over a passage length proportional to an inlet hydraulic diameter of the port inlet, wherein a ratio of the passage length to the inlet hydraulic diameter is equal to or greater than 4.
12. The gas turbine engine of claim 11 , wherein the ratio of the passage length to the inlet hydraulic diameter is between 4 and 8.
13. The gas turbine engine of claim 11 , further comprising one or more bends in the fluid passage between the port inlet and the port outlet.
14. The gas turbine engine of claim 13 , wherein each bend has a bend radius between one and two times an inlet hydraulic diameter of the port inlet.