How is exhaust gas temperature (EGT) obtained in a turbine engine?

Exhaust gas temperature (EGT) in a turbine engine is obtained with thermocouples positioned near the turbine exit. This method involves placing thermocouples strategically to measure the temperature of the exhaust gases as they exit the turbine section of the engine.

The thermocouples work based on the principle of thermoelectricity, where two different metals are joined at two points, creating a voltage that correlates with temperature differences. By measuring the voltage generated at the thermocouple junction located in the exhaust stream, an accurate reading of the gas temperature can be obtained. This measurement is critical for engine performance analysis and monitoring, as it allows for the detection of abnormal operating conditions and helps prevent potential damage due to overheating.

Utilizing pressure sensors does not provide direct temperature readings; they measure the pressure of gases instead. Air velocity measurements, while useful for certain engine parameters, are not indicative of the exhaust gas temperature. Similarly, oil temperature readings relate to the lubrication system of the engine and do not directly reflect the conditions in the exhaust system. Thus, using thermocouples near the turbine exit is the preferred and most effective method for obtaining EGT in turbine engines.