Development of High Precision Thermo-Anemometer

Abstract

An improved system of thermo-anemometer was developed. Temperature compensator was designed based on more accurate equations. Assumptions in the temperature compensation equation were minimized to make minute adjustment in each part of the circuit. An improved corrector circuit reduced the error of the velocity signal to be less than ±1% up to about 120°C. A new digital delay device was designed. Deviations from the specification of delay device could be adjusted by employing an automatic amplitude and mean voltage adjuster. Consequently, it can regenerate the original velocity waveform quite accurately, free from wave deformation and electrical noise up to 6kHz. Calibration time was reduced. The present device can obtain higher correlation terms in the thermal flow fields more accurately.