Diffuser with controlled diffused air discharge

A diffuser case for a gas turbine engine to provide discharge air for engine service applications, comprising:

• a first diffuser region having an outer wall and an inner wall diverging relative to each other defining an annular passage for the flow of compressed air;
• struts extending between the walls, wherein each of the struts include an interior passageway;
• a second diffuser region defined by the outer and inner walls diverging with respect to the airflow direction, the second diffuser region located downstream of the first diffuser region and upstream of the combustor, the second diffuser region further diffusing the compressed air, further decreasing the velocity and increasing the static pressure of the compressed air;
• a plurality of discharge orifices located in the second diffuser region radially internal of and external of the annular airflow path, the orifices accepting diffused air from the second diffuser region;
• a plenum located radially internal of the airflow path, said plenum surrounding the first diffuser region and being connected to the internal orifices for accepting diffused air from the internal orifices;
• a manifold located radially external of the airflow path and connected to the external orifices;
• the internal orifices connecting with the plenum, the plenum connecting with the struts to define a plurality of first passageways for flowing diffused discharge air to the manifold;
• the external orifices connecting with the manifold defining a plurality of second passageways for flowing diffused discharge air to the manifold;
• wherein the diffused air from the second diffuser region flows to the plenum and to the manifold, the manifold storing the diffused discharge air to be used for service applications.