Turbomachine Exhaust Case Secondary Flow Integration

A secondary flow vein is introduced as an intermediary pathway between the high-pressure compressor outlet and the exhaust casing. This intermediate channel allows the hot compressed air to be transported away from the primary flow path, enabling effective flow evacuation while isolating the noise and thermal stress generation from the main exhaust system.

The exhaust casing is divided into a primary flow path and a secondary flow path. The secondary vein is segmented from the main exhaust structure, with separate walls and flow channels. This segmentation allows independent optimization of each path - the primary path handles exhaust while the secondary path manages the hot compressed air transport, reducing mutual interference and harmful effects.

The secondary vein walls are merged directly with the exhaust casing wall through an excess thickness portion of the casing wall. This integration eliminates the need for separate pipe components and complex assembly operations. The foundry can cast the entire structure as a single piece or pre-assembled units, significantly improving manufacturability while maintaining the flow reintroduction capability.

The secondary vein is positioned in a radial dimension relative to the exhaust casing, with the vein walls formed by excess thickness of the casing wall itself. This dimensional approach allows the complex three-dimensional geometry to be achieved through controlled material distribution in the casting process, overcoming traditional foundry geometric constraints.