For air flowing through N2 and N3 compressors, what is the combustion to cooling air ratio?

The correct combustion to cooling air ratio within the context of N2 and N3 compressors is indeed 1:3. This means that for every unit of combustion air, there are three units of cooling air used. The ratio is crucial for maintaining optimal engine performance and efficiency during operation.

In compressor systems, the combustion air is essential for the combustion process within the engine, enabling the burning of fuel for power generation. Conversely, cooling air is vital for dissipating heat generated during combustion and the compressor operation, thereby preventing overheating and ensuring the longevity of engine components.

The specific ratio of 1:3 indicates a design choice aimed at balancing combustion needs with effective cooling. An adequate supply of cooling air relative to combustion air helps maintain the temperature within safe limits, ensuring efficient combustion and overall system stability.