Pomiary strumienia objętości przepływu w aspekcie dynamiki anemometrycznych czujników pomiarowych

Comparative analyses was performed of vane anemometers and two types of wire sensors intended for measurements of velocity vectors: a hotwire anemometer and that comprising thermistores PT100. Measurements were implemented inside a wind tunnel, in the mine heading and in the face region. Sensors in laboratory conditions were calibrated prior to and after the comparative tests, thus enabling the quantitative comparison. In the mines such calibration procedure was not possible, which further enhanced the uncertainty involved in hot-wire measurements as the hot-wire sensors are most sensitive to ambience conditions. Recordings of transients revealed a phenomenon already reported in literature, i.e. the slower response of vane anemometers to velocity decrease than increase. Laboratory tests, however, did not reveal major tendency of the vane anemometers’ readings to become too high due to velocity fl uctuations. Measurements taken in the mine provided data on the level of fl ow fl uctuations, enabling us to estimate the uncertainty component associated with fl ow fl uctuations. The system implementing multi-point measurement of velocity fi elds was subjected to the validation procedure. The system, which allows for fi nding the volumetric fl ow rates of passing air, is mounted in the test chamber inside the wind tunnel. The measurement data were then compared by relating them to airfl ow rates in the test chamber. Sensors making up the system were located at a close distance to the straightening vane installed at the inlet to the wind tunnel, in the region where it is reasonable to expect airfl ow fl uctuations. To facilitate the testing in the mine conditions, a hot-wire sensor was engineered utilising parallel elements PT100, to enable the measurements of velocity vectors in that plane.