A method to determine the measurement volume for particle shadow tracking velocimetry (PSTV)

A method to determine the depth of detection (DOD) for particle shadow tracking velocimetry (PSTV) is presented. In contrast with other image-based velocimetry techniques, PSTV is capable of measuring particle velocity in a volume of the flow. However, a precise methodology to determine the size of the measurement volume was not available (in particular, for internal flows in tubes with circular cross sections). To correct this shortcoming, we determined the range of distances in which the particles could be clearly identified. This was accomplished by displacing a calibration target across the camera’s field of view and by implementing appropriate filtering algorithms. The method was tested with a polydispersed gas-particle flow inside a tube. We found that the significantly improved particle count resulted in an unbiased statistical convergence of the data. .