TOMOGRAPHIC MEASURING TECHNIQUES - VISUAL IZATION OF BINARY FLOW

Some applications of electrical tomographic techniques for the measure ment of gas/liquid flows in packed columns are described. Electrical t omography is nonintrusive, of high temporal resolution, low cost, enge nders no radiation hazard and is easy to implement. This mainly encour ages the development of capacitance, resistance and inductance sensing techniques which are applied within volumetric fields of density, pre ssure, concentration, temperature, velocity or void fraction. The ment ioned fields are instationary most of the time or they are of transien t character. Therefore, not only temporal but also spatial resolution is required. X-ray tomography is used for the visualisation of gas-liq uid flow inside packed columns. The measurement system consists of a f ixed X-ray tube and an array of 15 detectors. The spacial resolution i s of the order of 0.4 x 0.4 mm, the temporal resolution is increased b y use of only 12 steps of rotation and a filtered back-projection algo rithm.