THERMOANEMOMETER WITH DC FEEDBACK

A brief description is given of a thermoanemometer which measures the mean velocity of air flow (up to 120 m/sec) and velocity pulsation intensity up to 10,000 c,. Compensation of thermal inertia of the filament is realized with the aid of a feedback amplifier, which makes a corresponding current regulation of filament heating current and automatically maintains the resistance of this filament. The instrument has a special amplifier, rectifying the non-linear dependence of the signal upon the rate of flow coming from the filament. Measurement of mean square root values of velocity pulsation is made with the aid of a pulsation amplifier, vacuum thermocouple, and thermo EMF amplifier.
Unedited rough draft trans. of Politekhnicheskii Institut, Leningrad. Trudy (USSR) n217 p176-9 1961.