What percentage of air from the compressor is used for cooling, seal pressurization, and ship service use?

The correct choice reflects that a significant portion of the compressed air produced by a gas turbine's compressor is diverted for purposes beyond combustion. In gas turbine systems, approximately 70% of the air is indeed used for cooling the turbine components, seal pressurization, and supporting ship service systems. This allocation is crucial for maintaining operational efficiency and extending the lifespan of the turbine. Cooling helps manage the extreme temperatures generated during combustion, while seal pressurization prevents hot gases from leaking into unwanted areas, thus improving performance and safety. The remaining air, approximately 30%, is supplied for the combustion process itself, where it mixes with fuel to produce the necessary thrust or power. This percentage highlights the engineering balance between optimal combustion and the thermal management required in gas turbine operations.