Coolant airflow assembly particulate filter with panels in series

1. A coolant airflow assembly for a gas turbine engine, comprising:

a coolant feed passage connected between a supply of coolant air and an inlet of a component to be cooled, the coolant feed passage defining a coolant airflow path and comprising first and second opposing internal faces, the inlet of the component connected to the coolant airflow path through one of the first and second internal faces of the coolant feed passage; and

a particulate filter for removing entrained particles from the coolant airflow path, comprising:

a first filter panel extending from the first face into the coolant airflow path upstream of the inlet of the component; and

a second filter panel extending from the second face into the coolant airflow path upstream of the first filter panel,

wherein the coolant airflow path between the first filter panel and the second face, between the second airflow panel and the first face, and between the first filter panel and the second filter panel each has a minimum cross-sectional area no smaller than a cross-sectional area of the inlet of the component to be cooled.

2. The coolant airflow assembly of claim 1 , comprising an airflow deflector extending from the first face into the coolant airflow path upstream of the second filter panel.

3. The coolant airflow assembly of claim 1 , wherein the first filter panel comprises a first portion extending from the first face of the coolant feed passage into the coolant airflow path and a second portion extending from an end of the first portion in the coolant airflow path in a downstream direction.

4. The coolant airflow assembly of claim 3 , wherein the first portion is curved and has an upstream-facing inner concave surface.

5. The coolant airflow assembly of claim 3 , wherein the supply of cooling air comprises particles and the first filter panel comprises a plurality of passages through the panel, the passages being sized to capture particles entrained in the coolant airflow path.

6. The coolant airflow assembly of claim 5 , the component having film cooling holes having a diameter, wherein the passages are sized to capture particles greater than half of a minimum film cooling hole diameter in the component to be cooled.

7. The coolant airflow assembly of claim 6 , wherein the passages have a diameter of between 0.1 and 1 mm.

8. The coolant airflow assembly of claim 1 , wherein the first filter panel comprises a curved first portion having an upstream-facing inner concave surface.

9. The coolant airflow assembly of claim 1 , wherein the second filter panel comprises a first portion extending from the second face of the coolant feed passage into the coolant airflow path and a second portion extending from an end of the first portion into the coolant airflow path in an upstream direction.

10. The coolant airflow assembly of claim 9 , wherein the second filter panel comprises a plurality of passages through the panel, the passages being sized to capture particles entrained in the airflow path.

11. The coolant airflow assembly of claim 9 , the component having film cooling holes having a diameter, wherein the passages are sized to capture particles greater than half of a minimum film cooling hole diameter in the component to be cooled.

12. The coolant airflow assembly of claim 1 , comprising a bypass passage in the first face of the coolant feed passage upstream of the first filter panel.

13. The coolant airflow assembly of claim 1 , wherein the first and second filter panels are integrated into a common panel having an airflow passage between the first and second panels defined in series by an inlet through one hole in the common panel and an outlet through a further hole in the common panel.

14. The coolant airflow assembly of claim 1 , wherein the component to be cooled is one or more nozzle guide vanes or one or more turbine blades.

15. A gas turbine engine comprising a coolant airflow assembly, comprising:

a coolant feed passage connected between a supply of coolant air and an inlet of a component to be cooled, the coolant feed passage defining a coolant airflow path and comprising first and second opposing internal faces, the inlet of the component connected to the coolant airflow path through one of the first and second internal faces of the coolant feed passage; and

a particulate filter for removing entrained particles from the coolant airflow path, comprising:

a first filter panel extending from the first face into the coolant airflow path upstream of the inlet of the component; and

a second filter panel extending from the second face into the coolant airflow path upstream of the first filter panel,

wherein the first and second filter panels do not extend across a full width of the coolant feed passage, and

wherein the first and second filter panels do not contact each other, the first and second filter panels including unrestricted airflow regions therebetween.

16. The gas turbine engine of claim 15 , wherein the first and second filter panels comprise a plurality of passages through the respective panels, the passages being sized to capture particles entrained in the airflow path.

17. The gas turbine engine of claim 16 , wherein the passages have a diameter of between 0.1 and 1 mm.

18. The gas turbine engine of claim 17 , comprising a bypass passage in the first face of the coolant feed passage upstream of the first filter panel.

19. The gas turbine engine of claim 15 , wherein the coolant airflow path between the first filter panel and the second face, between the second airflow panel and the first face, and between the first filter panel and the second filter panel each has a minimum cross sectional area no smaller than a cross-sectional area of the inlet of the component to be cooled.

20. A coolant airflow assembly for a gas turbine engine, comprising:

a coolant feed passage connected between a supply of coolant air and an inlet of a component to be cooled, the coolant feed passage defining a coolant airflow path and comprising first and second opposing internal faces, the inlet of the component connected to the coolant airflow path through one of the first and second internal faces of the coolant feed passage; and

a particulate filter for removing entrained particles from the coolant airflow path, comprising:

a first filter panel extending from the first face into the coolant airflow path upstream of the inlet of the component; and

a second filter panel extending from the second face into the coolant airflow path upstream of the first filter panel;

wherein the first and second filter panels are integrated into a common panel having an airflow passage between the first and second panels defined in series by an inlet through one hole in the common panel and an outlet through a further hole in the common panel;

wherein the first and second filter panels do not extend across a full width of the coolant feed passage,

wherein the holes have a diameter of between 0.1 and 1 mm, and

wherein the coolant airflow path between the first filter panel and the second face, between the second airflow panel and the first face, and between the first filter panel and the second filter panel each has a minimum cross sectional area no smaller than a cross-sectional area of the inlet of the component to be cooled.