General discussion

Abstract

In order to analyse quantitatively the images obtained by using the Radiation Dynamics Super X, 8 MeV linear accelerator, Rolls-Royce have developed a system of close-range X-ray photogrammetry. In order to study the behaviour of components in motion, it is necessary to provide a flow of images from which specific events may be identified in a qualitative manner to allow a radiograph to be made for detailed measurement purposes. The use of real-time video techniques also allows the speed of an event or the rate of flexure of components to be determined, giving an indication of the nature of the force creating the movement. This may, for instance, be a thermal growth which may be slow or a pressure force which is likely to be more rapid in change. By using the Super X in the stroboscopic mode linked to engine speed, it is possible to identify eccentricity of compressor spacer rings. The video then allows the determination of the time when the ring becomes free and eccentric.