Introduction

In November 2007, Derek Pullen kindly donated a number of original film radiographs of historical importance to the Shaw Inspection Systems Image Library. Amongst other firsts in a long and distinguished career, Derek was involved in pioneering radiography of gas turbine engines. The film radiographs donated by Derek are from this ground breaking imagery.

Film Digitisation

These film radiographs have been digitised using a Kodak LS85 Film Digitizer at 254dpi (0.1mm per pixel) to provide a 12-bit image. For the purposes of this website, the 12-bit images have been contrast stretched, before conversion to 24-bit colour (8-bit grey scale).

All the radiographs, with the exception of the two cold neutron radiographs are 14" x 17", which have a digitised size of approximately 3500 x 4200 pixels. The cold neutron radiographs are smaller (12" x 15.5") and have a digitised size of 3000 x 3900 pixels. All the radiographs are copies of the originals, which were exposed over 30 years ago.

Figure 3, 1981 Paper

Two (A & C) of these four radiographs were used for Figure 3 of Derek's 1981 paper titled 'Radiographic Photogrammetry yields valuable data in studies of running Gas Turbines'. The caption for this figure reads, 'An unexpected variation in a turbine seal between two different engine conditions would have been very difficult to verify without radiography, if even possible.'. From Derek's own notes Radiograph A is of the High Pressure (HP) Turbine of a large turbojet engine. The focal point is the rear root seal on the HP1 disc. The engine was static (cold). Radiograph B is for the same position, but with the engine running at a low power setting. Note the movement of the seal. Radiograph C is in the same position, but with the engine in a high power setting. The seal has moved even further and become disengaged.

Figure 7, 1981 Paper

These two cold neutron radiographs were used for Figure 7 of Derek's 1981 paper titled 'Radiographic Photogrammetry yields valuable data in studies of running Gas Turbines'. The caption for this figure reads, 'Two neutron radiographs of an engine. The left view of a static condition and the right view with the engine running. The oil is liquid in the static view and aerated in the dynamic view.'. From Derek's own notes Radiograph D is a cold neutron radiograph of a static helicopter turbine showing liquid lubricant in the central shaft (half full), the scavenge chamber and downpipe, and a vapour bubble in the horizontal scavenge pipe below. neutron radiograph of the same engine running, showing the central shaft full of lubricant which is also jetting out of the end bearing into the scavenge chamber. The lubricant in the scavenge down pipe is heavily aerated, and there is a large vapour lock in the horizontal scavenge pipe below. These two radiographs enabled remedial action to be taken to overcome these problems

Other Radiographs

This set of radiographs are aligned on the rear end of the High Pressure Compressor and the front of the Combustion Chamber of a large turbofan engine. Radiograph F is with the engine cold static, and the other two radiographs are at different power levels.

References