Abstract
Gas turbine designers demand accurate predictions of metal temperature to ensure acceptable operating life of components experiencing high thermal stress. Rotor-stator cavities ingest hot mainstream gas through rim seals when inadequately purged with relatively cool air bled off the compressor. Superfluous use of purge, and any associated windage increase, creates a parasitic loss in overall efficiency. Shear interaction caused by the difference in swirl between the purge and mainstream flow is a principal driver for ingestion; pre-swirled purge flow has the potential to alter the swirl gradient. This paper presents the first assessment of purge conditioning in a downstream cavity.
An experimental campaign was conducted in a new aeroengine representative 1.5-stage test facility designed to facilitate expedient changeover of modular components in the downstream stator assembly. Purge flow in the downstream cavity was supplied through a series of angled injectors contained in a single component at mid-radius. Three co-swirled injection angles were tested.
Measurements of CO2 gas concentration, static pressure and swirl were taken in the cavity to examine the relationship between purge-mainstream swirl gradient and ingress downstream of a rotor blade. The aero-engine designer must balance caution when employing pre-swirl to reduce disc windage; co-swirled purge increased the purge-mainstream swirl gradient and subsequently increased shear-driven ingestion.
An experimental campaign was conducted in a new aeroengine representative 1.5-stage test facility designed to facilitate expedient changeover of modular components in the downstream stator assembly. Purge flow in the downstream cavity was supplied through a series of angled injectors contained in a single component at mid-radius. Three co-swirled injection angles were tested.
Measurements of CO2 gas concentration, static pressure and swirl were taken in the cavity to examine the relationship between purge-mainstream swirl gradient and ingress downstream of a rotor blade. The aero-engine designer must balance caution when employing pre-swirl to reduce disc windage; co-swirled purge increased the purge-mainstream swirl gradient and subsequently increased shear-driven ingestion.
| Original language | English |
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| Title of host publication | Proceedings of the ASME Turbo Expo 2025: Turbomachinery Technical Conference and Exposition |
| Subtitle of host publication | General Interest/ Additive Manufacturing Impacts on Heat Transfer; Heat Transfer: Internal Air Systems; Heat Transfer: Internal Cooling; Industrial and Cogeneration |
| Place of Publication | U. S. A. |
| Publisher | American Society of Mechanical Engineers (ASME) |
| ISBN (Electronic) | 9780791888827 |
| DOIs | |
| Publication status | Published - 11 Aug 2025 |
| Event | ASME Turbo Expo 2025: Turbomachinery Technical Conference and Exposition - Memphis, Tennessee, USA Duration: 16 Jun 2025 → 20 Jun 2025 |
Publication series
| Name | Proceedings of the ASME Turbo Expo |
|---|---|
| Volume | 6 |
Conference
| Conference | ASME Turbo Expo 2025: Turbomachinery Technical Conference and Exposition |
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| Period | 16/06/25 → 20/06/25 |
Funding
The authors would like to acknowledge the technical expertise and support of Andrew Langley and Sam L’esteve, both of whom were key to the construction and commissioning of the IRIS experimental facility. The authors would also like to thank Safran Aircraft Engines for funding this programme.