Recent Advances in
Measurement Technology
for Turbomachinery Applications

Abstract: In recent years, progress in measurement technology enabled refined turbomachinery research and advanced technology development. The present work aims to review recent advances in turbomachinery measuring techniques. In particular, attention is focussed on intrusive measurement technologies, including point measurement techniques. Various types of probes, traditional and novel, are being examined with respect to their capacity to provide accurate reference data. In the dawn of the new millennium, the need for unsteady measurement techniques, suitable for turbomachinery applications, became more intense. The ascent of the modern design methodologies, requiring unsteady data for reference, made the development of suitable measurement technologies, urgently required. At the same time, progress in numerical modelling of complex turbomachinery geometries as well as turbomachinery modelling accentuated the need for more accurate reference data to facilitate further development.

Over the last 25 years, pioneering research work at ETH Zurich lead to technology development, which made possible the development of the Fast Response Aerodynamic Probe (FRAP) technology. Inspirational work in Cambridge has lead scientists and engineers, to develop unsteady numerical methods and measurement techniques, aiming to evaluate the loss generation mechanisms by means of the entropy function. The work at a number of leading institutions worldwide has contributed to establishing the need for advanced and reliable experimental techniques. The advent of fast response sensor technology and precision manufacturing enabled the development of fast and accurate aerodynamic probes, which operate reliably in a wide range of realistic turbomachinery applications. Overall, the application of these techniques extents to both compressors and turbines ranging from small and low speed air conditioning fans to large multistage aeroengine and power generation turbomachinery units. Recent advances have also, addressed measurements in the wet steam areas of large multistage steam turbines. The development of miniaturised on board electronics enabled rotating frame of reference measurements, enhancing the previously limited range of application. Furthermore, progress in artificial intelligence methods, applied to probe navigation through complex turbomachinery flow fields, have enabled the optimisation of data acquisition processes, minimising the impact of measurements to the final product. Finally, averaging techniques applied to cloud-of-point-measurements are also under consideration. This work concludes with an outlook of future developments in measurement technology for turbomachinery applications.