One objective of the ENOVAL project is to achieve a significant reduction in effective perceived noise levels, with an overall goal of -1.3 EPNdB. The development of validated technologies to increase turbine efficiency and reduce turbine noise for future UHBR engines in ENOVAL contributes to achieving this objective. In this context, the use of low noise designs via Computational Fluid Dynamics (CFD) has been investigated as an alternative to traditional practices. A proper validation of these tools is required to obtain reliable results, especially when seeking advanced noise technologies that allow more competitive and greener products.
ENOVAL WP4.4, led by ITP, is dedicated to the development of low pressure turbine technologies. The scope of work includes calibration of CFD tools with state-of-the-art turbine experimental results, the design and test of high TRL (Technology Readiness Level) experiments, and two turbine rig tests in an altitude test facility.
ITP and the Spanish aerospace test laboratory CTA based in Zamudio successfully completed the first rig test campaign in early 2015. The aim of this rig test was to reach TRL 5, i.e. validation in a relevant environment, for the proposed noise reduction technologies developed in WP4.4.
Existing rig hardware from Clean Sky SAGE3 was redesigned to optimize cost and lead times. The rig features a 3-stage turbine and is representative of the central stages of a low pressure turbine. The test focused on the impact of the noise reduction technologies at different test conditions representative of engine noise operating conditions (i.e. cutback, sideline and approach). Therefore, accurate noise measurements were required.
An upgraded 360º rotating noise module initially developed within the EU project VITAL was used. Upgrade consisted of including acoustic treatments for the isolation of facility noise and spurious reflections to reduce measurement uncertainties.
The evaluation of test results to derive final conclusions is still ongoing, and final results are expected for September 2016.