Application of laser diode in airplane engine nozzle temperature measurement system

Thermoelectric couple was employed in traditional airplane engine nozzle temperature measurement system with the disadvantages of large size, heavy weight, big error and slow response. This paper presents a new kind of real—time temperature measurement system using laser diode InGaAs/I as light source, and using pyroelectric detector LiTa03 as optical receiving unit and using a microprocessor as signal processing center. This instrument consists of three parts: optical emitting and receiving system, signal amplifying and controlling system, and display system. The principle, structure, anti—interference measure of the system are introduced. Experimental results of airplane engine real—time temperature measurement show that temperature measurement accuracy and response time conform to our requirement in the range of 300°C一800°C and agree with prediction of theory. All these prove that the design is correct.