Determining the time constant using two methods and defining the thermocouple response to sine excitation of gas turbine

This paper describes the two methods of determining the time constant of type K thermocouple, for two construction solutions: the exposed weld and the mantle fillet weld. This is an important parameter indicating the response time of the thermocouple on the recorded signal. The first method consists of determining the value of τ in the way of numerical simulation of heat exchange between the thermocouple and the current of gas [2] for the parameters adopted for the gas and for the known construction of the temperature sensor. The second method is a graphical determination of these parameters on the basis of the sequence of high frequency temperature of gas. The study was conducted to determine the position of the dynamic properties of thermocouples [3]. Based on these results was made the choice of the thermocouple with the best dynamic properties, which helped during the tests on the reciprocating compressor [4]. On the basis of the sequence of high frequency temperature and gas pressure was determined the response of the thermocouple on the sine excitation of gas temperature (the phase and amplitude displacement of the sequence) [5]. The used method of signal correction was rated and its suitability for diagnostic testing of piston machines was determined.