BONHAM, C. ... et al, 2017. Combination probes for stagnation pressure and temperature measurements in gas turbine engines. Measurement Science and Technology, doi: 10.1088/1361-6501/aa925c.
During gas turbine engine testing, steady-state gas-path stagnation pressures and temperatures are measured in order to calculate the efficiencies of the main components of turbomachinery. These measurements are acquired using fixed
intrusive probes, which are installed at the inlet and outlet of each component at
discrete point locations across the gas-path. The overall uncertainty in calculated component efficiency is sensitive to the accuracy of discrete point pressures and temperatures, as well as the spatial sampling across the gas-path. Both of these aspects of the measurement system must be considered if more accurate component efficiencies
are to be determined. High accuracy has become increasingly important as engine
manufacturers have begun to pursue small gains in component performance, which
require efficiencies to be resolved to within less than ±1%. This article reports on three new probe designs that have been developed in a response to this demand. The probes adopt a compact combination arrangement that facilitates up to twice the spatial coverage compared to individual stagnation pressure and temperature probes. The probes also utilise novel temperature sensors and high recovery factor shield designs that facilitate improvements in point measurement accuracy compared to standard
Kiel probes used in engine testing. These changes allow efficiencies to be resolved
within ±1% over a wider range of conditions than is currently achievable with Kiel probes.
This paper is closed access until 10th October 2018. This is an author-created, un-copyedited version of an article published in Measurement Science and Technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1361-6501/aa925c.