ADVANCED HOT-WIRE ANEMOMETRIC MEASUREMENT SYSTEMS IN INVESTIGATION OF THE AIR FLOW VELOCITY FIELDS IN MINE HEADINGS

In this study, presented are the advanced hot-wire anemometric measurements systems suitable for investigation of velocity fields in mine headings. A construction of two types of modernized three-element hot-wire anemometric probes is discussed. The three-element wire sensor which was used only under laboratory conditions up to date was added a fourth element, enabling the temperature compensation. The second type of sensor suitable for determination of the flow velocity vector under conditions prevailing in mine headings is equipped with spatial system of three cylindrical platinum-ceramics microsensors constituting a measurement basis and a temperature compensation clement. In subsequent section discussed is the measurement equipment consisting of two eight-channel constant-temperature constant-current hot wire anemometric modules which, together with specialized software and a set of vector probes, comprises the system for investigation of three-dimensional flow structures in mine headings. Prior to comparative measurements in mine headings, the characteristics of velocity sensors needed to be determined. To this end an accredited laboratory of the Institute was employed in which the calibration of measurement instruments in wind tunnel was performed according to established procedures. As a result, the characteristics with known uncertainties were obtained (Chmiel et al., 2003; Krach, 2009). Results of initial tests in the environment of an underground mine have been presentedd.