Simultaneous measurement of velocity and concentration in flow of two gases mixture is required at several wind tunnel experiments, e.g. modeling of pollutant dispersion. A thermoanemometer is a suitable tool for such measurements owing to it broad dynamic range for measurement of velocity and concentration fluctuations. The paper presents a measurement method by means of a special dual hot-wire probe (modification of the DANTEC t. 55P71) in a stream of the air/CO2 mixture. The in-house developed procedure of the simultaneous measurement of both the mean and the r.m.s. values of concentration and velocity was applied to investigation of a gaseous carbon dioxide round jet spreading into a collateral air flow. Performed experiments indicate that the applied measurement method might be useful for the turbulent diffusion investigations in complex conditions. They also confirm the usability of carbon dioxide as a tracer gas in modeling of gaseous pollutant spreading.
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The method of investigation of the flow structure and correlation velocity/temperature fields in the LP stage using a CTA anemometer is outlined in the contribution. The arrangement of the rotary slanted hot-wire probe equipped with a resistance thermometer and a pressure transducer is described that makes possible to correct the CTA-readings from the effect of the steam state small variations and from the disturbances caused by the impacts of large water droplets on the heated wire. Next some details of the synchronized sampling of CTA output voltage and the evaluation of the results are presented.