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Photogrammetry For Engineering Research And Development Using High Speed Photography And Video

Photogrammetry, the science of measurement from images may be either two or three dimensional in nature utilising single images or pairs of stereoscopic images. The technique was developed originally at RR APD for the measurement of images from high energy x-radiography or neutron radiography. Recently, a programme of research has been carried out using a double flash argon spark source to arrest the motion of bubbles in a flowing stream of lubricating oil - two phase flow. A pair of stereoscopic images with single or double exposure have been obtained providing material for subsequent analysis in a stereocomparator It has been possible to derive information on local flow velocities from the double exposures and to measure the volume of gas in the bubbles flowing in the liquid - the so called void fraction. From a system calibration it has been possible to obtain local two phase pressure drop non-invasively using photogrammetry. A high speed video system, the spin physics SP2000 has been used to take mono and stereoimages of bubbles at 2000 pictures per second. Using the freeze frame mode it has been possible to obtain three dimensional images and obtain a better understanding of the dynamics of the various flow regimes. The SP2000 has now also been used to analyse a number of other engineering problems including flow from a reheat burner ring, birdstrike problems and the laser drilling of holes. The SP2000 has been found to be fast in its acquisition and display of images and the measurement system has provided quantitative information a short time after the experimental work. It is intended to pursue further the largely untouched field of high speed video - photogrammetry using the SP2000.