A cooling structure for the flame cylinder and the elbow of the backflow combustor

Abstract

The invention discloses a cooling structure for a recirculation combustion chamber, which comprises a flame tube outer ring, a flame tube inner ring, a large bend, a small bend and a flame tube head. One end of the flame tube outer ring is provided with a large bend, a large bend It is a ring structure, the other end of the flame tube outer ring is provided with a flame tube head, the inside of the flame tube outer ring is provided with a flame tube inner ring, and the end of the flame tube inner ring close to the large bend tube is provided with a small bend; the flame tube outer ring , which is provided with a plurality of outer ring mixing holes, and is divided into a plurality of first L-shaped unit bodies along the circumferential direction; the small elbow is in a ring structure, and is divided into a plurality of second L-shaped unit bodies along the circumferential direction . The invention belongs to the technical field of cooling, and the cooling efficiency of an L-shaped cooling elbow is higher than that of a conventional cooling elbow; the L-shaped cooling elbow is not easy to be ablated; the L-shaped cooling elbow can reduce the cost of sheet metal processing; The assembly of the segmental lap welded structure of the pipe is simple and easy to realize.

Description

technical field [0001] The invention belongs to the technical field of cooling, and in particular relates to a cooling structure of a backflow combustion chamber flame cylinder and an elbow pipe. Background technique [0002] Small and medium-sized aeroengines usually use a recirculation combustion chamber to match the shorter engine wheelbase and smaller engine inlet frontal area. Compared with the once-through combustor, the surface area to volume ratio of the recirculation combustor flame tube is higher, which makes the cooling of the recirculation combustor flame tube more difficult, especially the cooling problem of the elbow. Because the last stage compressor of small and medium-sized aero-engines usually uses a centrifugal compressor, and due to the specific structural shape of the centrifugal compressor, the airflow velocity in the annular cavity between the compressor and the large elbow of the flame tube is usually low, and the airflow passes through the compressor...

AI Technical Summary

Problems solved by technology

Because the last stage compressor of small and medium-sized aero-engines usually uses a centrifugal compressor, and due to the specific structural shape of the centrifugal compressor, the airflow velocity in the annular cavity between the compressor and the large elbow of the flame tube is usually low, and the airflow passes through the compressor The flow out of the diffuser usually has a certain angular velocity, which makes the cooling intake conditions of the large curved pipe of the flame tube of the return flow combustion chamber relatively poor, and the cooling of the large curved pipe is difficult

On the other hand, the small elbow of the return combustion chamber usually adopts a profile design with large curvature and rapid transition, and problems such as poor airflow adherence to the wall and air separation caused by the large curvature surface also make it difficult to cool the small elbow

[0003] As the thrust-to-weight ratio (power-to-weight ratio) of the engine continues to increase, the temperature and pressure of the combustion chamber intake air increase, the combustion room temperature rises, and the heat capacity continues to increase, which also makes the overall cooling of the combustion chamber more difficult. The quality of cooling air decreases, which increases the difficulty of cooling design

When the cooling design of the flame tube of the recirculation combustion chamber is unreasonable and the cooling air volume is too small, problems such as ablation, cracks, and coating loss may occur on the wall of the flame tube during the heating process, and the elbow is directly washed by the upstream gas, and the heat Higher strength may cause local burn-through, resulting in changes in the intake conditions of the flame tube, resulting in failure of the flame tube and combustion chamber

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