CMSC 2018 Presentation - Long Duration Photogrammetric Monitoring of Turbine Deformation at High Temporal Frequency

Publication Details

Abstract

As a non-contact 3D measurement technology, photogrammetry has long been applied in deformation monitoring. Applications have ranged from the measurement of deformation of large-scale engineering structures such as bridges, buildings and dam walls, to steel beams under both structural and thermal loading in industrial manufacturing. One such application is the measurement of turbines to ascertain changes in both alignment and casing deformation that accompany thermal loading associated with hot/cold turbine restarts. This paper discusses multi-temporal photogrammetric measurement of turbines in general, including issues such as references systems to support determination of absolute and relative deformation, aspects of targeting and image acquisition, and the need for highly automated data processing workflows to support the potentially very large number of measurement epochs involved. The case of a long-duration, high temporal frequency deformation measurement of two turbines is considered to highlight the concepts discussed. In this particular case, it was required to determine surface displacements on the outer turbine casing related to the changing thermal gradient accompanying start-up. An initial photogrammetric survey was conducted to establish a reference system tied to the axial alignment of the turbine, and then the multi-epoch deformation monitoring surveys commenced, with one epoch of measurement being conducted every 15 minutes over more than a 24-hour period. Such a project poses some interesting practical challenges, which photogrammetry can readily accommodate, and these are also discussed.