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ISSN Online: 2377-424X

ISBN Print: 0-89116-299-2

International Heat Transfer Conference 7
September, 6-10, 1982, Munich, Germany

TRIPLE HOT-WIRE TECHNIQUE FOR MEASUREMENTS OF TURBULENCE IN HEATED FLOWS

Get access (open in a dialog) DOI: 10.1615/IHTC7.2700
pages 491-496

Аннотация

A four-wire, hot-wire system has been developed which measures in real time the instantaneous values of the velocity components, corrected to account for the local fluid temperature without invoking the "low turbulence" assumption. This technique also eliminates the time-averaging ambiguities present in the rotatable slant-wire approach. Tests on isothermal flows show that mean velocity and the turbulent shear stress u'v’ can be measured within 1.4% and 4.8%, respectively, if the velocity vector lies within 20° of the probe axis.

The temperature-compensated velocity signals remained accurate within 2% over a change in fluid temperature from 18 to 42°C. The analog devices used in the overall circuitry were shown to produce less than 2° phase shift and less than 0.1% attenuation over the frequency range from DC to 20,000 Hz. Temperature fluctuations up to 3 kHz should be accurately handled by the circuit, but only slow changes in temperature have been tested as yet.