Abstract
The time response of TI-, TM- and intrinsic thermocouples has been investigated in sodium by determination of frequency dependent thermocouple transfer functions and related delay times. Experimentally temperature fluctuations (temperature noise), generated in sodium by heated channels or injection of hot sodium, have been used as driving sources. The measured transfer functions and delay times have been compared to predictions from theoretical models. Good agreement was found. Intrinsic and TM-type thermocouples are best suited if fast response is required. Delay times in the range of one millisecond or upper break frequencies of 1000 Hz were determined for intrinsic thermocouples. The determination of sodium flow velocities by the transit time correlation technique showed systematic error sources for analysis at low frequencies due to intermediate heat storage between the thermocouple positions. Statistical errors have been determined as function of thermocouple distance, frequency range and time of analysis. Minimum errors are obtained for thermocouple distances from 100 to 150 mm and in the frequency range 90 to 120 Hz. A transit time correlator, which automatically tracks the maximum of the cross-correlation function and displays the velocity, has been successfully used for signals with correlation coefficients greater than 0.3.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
