كاربرد پروب الكتريكي يك و دوسوزني براي اندازه گيري در جريانهاي مخلوط آب و هوا

Application of One and Double Needle Electrical Probe for Measurement in Air-Water Flows

In the present paper application of a one-needle and a double-needle electrical probe with developed specifications is introduced for measurement in air-water flows. The new one-needle probe has the capability of measuring air concentration and bubble count with very high sampling frequency. Another advantage of this probe is real time measurement and on-line presentation of results. More than 30 sets of tests were carried out in air-water flows to calibrate the probe and to determine the circuit threshold level. To measure the velocity of air-water mixture a doubld-needle electrical probe is employed. The specifications of the double-needle probe are similar to the one-needle probe with addition of one needle to make it capable of measuring flow velocity. To ensure the performance of the double-needle probe, its measurements were compared with a pitot tube. This comparison showed that the maximum difference in measurements was less than 4%.