FAA Powerplant Written Practice Test

In terms of turbine engine cooling, what is the primary purpose of a liquid-to-liquid heat exchanger?

1. To regulate oil temperature

2. To enhance fuel atomization

3. To cool exhaust gases

4. To maintain air temperature for combustion

The correct answer is: To regulate oil temperature

The primary purpose of a liquid-to-liquid heat exchanger in turbine engine cooling is to regulate oil temperature. In turbine engines, maintaining the correct oil temperature is crucial for ensuring proper lubrication, minimizing wear and tear on engine components, and preventing overheating. The heat exchanger allows heat from the oil to be transferred to another liquid, which can help to cool the oil and maintain it within an optimal temperature range for engine operation. This regulated temperature is vital because oil that is too hot can lose its effectiveness as a lubricant, leading to increased friction and possible engine failure. Conversely, oil that is too cold may not flow properly or provide adequate lubrication during start-up and low-temperature operations. Therefore, the heat exchanger plays an essential role in maintaining oil temperature and ensuring the smooth operation of the turbine engine. Other options, while related to engine operation, do not accurately reflect the primary function of a liquid-to-liquid heat exchanger in the context of turbine engine cooling.