With the development of aero-engine technology, performance parameters such as thrust-to-weight ratio, turbine front temperature and total supercharging ratio have been significantly improved. Among them, turbine front temperature is not only an important performance parameter of aero-engine, but also is related to the temperature of turbine blade surface, turbine cooling, life extension control and other aspects, which greatly affects the reliability of aero-engine. Direct and accurate measurement of turbine front temperature is the prerequisite to meet the above technical requirements. And the development of temperature transmitter with large range, high precision and high stability which is suitable for aeroengine is the concrete way to achieve this.
Temperature transmitter is a device or equipment that can receive temperature signal and convert it into usable electrical signal according to certain sensing principles, usually including sensitive element and conversion element. According to the different nature of the measurement principle, the temperature transmitter can be divided into two types: Contact temperature measurement and contactless temperature measurement.
Contact temperature measurement refers to the direct contact between the sensitive element of the temperature transmitter and the measured object, and the thermal balance state is reached through the way of heat conduction. The temperature of the sensitive element represents the actual temperature of the measured object and then conduct measurement. The contact transmitters which are currently used or still under research in aero-engine include thermocouple temperature transmitter, temperature indicator paint, crystal high temperature transmitter and optical fiber high temperature transmitter, etc.
Contactless temperature measurement means that the sensing element of the temperature transmitter does not have direct contact with the measured object. But by obtaining the thermal radiation information of the measured object and calculating the temperature information of the measured object according to the corresponding relationship with the temperature, it can realize the temperature measurement of the measured object. Radiant high temperature transmitter is the main contactless transmitter which are currently used or still under research in aero-engines.