What happens to turbine temperature and thrust when air is extracted for other uses?

What happens to turbine temperature and thrust when air is extracted for other uses?

• A. Turbine temperature increases and thrust increases
• B. Turbine temperature decreases and thrust decreases
• C. Turbine temperature increases and thrust decreases
• D. Turbine temperature remains constant while thrust decreases

Answer: (C)

When air is extracted from the turbine for other uses, such as for cabin pressurization or anti-icing systems, the dynamics of the turbine operation are affected. The extraction of air leads to a decrease in the mass flow rate through the engine. As a result, less air is available for combustion in the engine, which means that the fuel-to-air ratio is altered. This change leads to an increase in turbine temperatures, as the remaining air that is still being combusted must carry away the heat from a lesser amount of fuel. Essentially, the overall efficiency decreases because less air means that the combustion process is not as effective as it could be under normal operating conditions. The increase in turbine temperature occurs because the engine is essentially trying to produce the same amount of power with a reduced airflow, leading to a rise in combustion temperatures. At the same time, because the mass flow through the turbine has decreased, the overall thrust produced by the engine will decline. With less air being accelerated through the turbine, the thrust output is inevitably reduced. The combination of these effects results in an increase in turbine temperature alongside a decrease in thrust, which aligns with the correct choice of extracting air leading to increased temperatures and reduced thrust.

When air is extracted from the turbine for other uses, such as for cabin pressurization or anti-icing systems, the dynamics of the turbine operation are affected. The extraction of air leads to a decrease in the mass flow rate through the engine. As a result, less air is available for combustion in the engine, which means that the fuel-to-air ratio is altered.

This change leads to an increase in turbine temperatures, as the remaining air that is still being combusted must carry away the heat from a lesser amount of fuel. Essentially, the overall efficiency decreases because less air means that the combustion process is not as effective as it could be under normal operating conditions. The increase in turbine temperature occurs because the engine is essentially trying to produce the same amount of power with a reduced airflow, leading to a rise in combustion temperatures.

At the same time, because the mass flow through the turbine has decreased, the overall thrust produced by the engine will decline. With less air being accelerated through the turbine, the thrust output is inevitably reduced. The combination of these effects results in an increase in turbine temperature alongside a decrease in thrust, which aligns with the correct choice of extracting air leading to increased temperatures and reduced thrust.