Unsteady hot gas ingestion through the double rim-seals of an axial gas turbine

Seungyeong Choi, Minho Bang, Seok Min Choi, Myung Hwan Cho, Hee Koo Moon, Hyung Hee Cho

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3 Citations (Scopus)


Rim-seals are exposed to one of the most complex flows in modern high-efficiency gas turbines. The flow physics in the vicinity of rim-seals should be understood before predicting the hot gas ingestion that may cause a rise in disc temperature and a catastrophic failure. To investigate the seal performance of rim-seals, experiments were performed using a high-speed rotating test-rig and followed up that the unsteady flow analysis approach was proposed. The rotating rig consisted of 1.5-stage axial turbines with a double rim-seal. Local pressures and CO2 concentrations were measured to evaluate flow characteristics and sealing performance. At a rotational Reynolds number of 1.0 × 106, the circumferential pressure distribution on the vane endwall platform and corresponding distribution of the circumferential sealing effectiveness of the rim-seal were measured. The results of the unsteady Reynolds-averaged Navier–Stokes (URANS) model were in a good agreement with the experimental results. Time-averaged, time-resolved flow observations under various conditions revealed unsteadiness of rim-seal flow; ingress and egress occurred repeatedly over time at all circumferential locations. The results validated unsteady ingestion from a reduction in sealing effectiveness of up to 30% at any instant compared to the time-averaged sealing effectiveness. As the rotational speed increased, the asymmetric pressure distribution of the main flow increased, and the average sealing effectiveness decreased up to 50%. The novelty of this study is that instantaneous hot gas-ingestions reached to a location significantly deeper into the disc cavity than that obtained from time-averaged predictions. It is concluded that understanding the nature of unsteady flow and its effects to hot gas-ingestion is vital to the reliable design of turbine rim-seals.

Original languageEnglish
Article number106664
JournalInternational Journal of Mechanical Sciences
Publication statusPublished - 2021 Oct 1

Bibliographical note

Funding Information:
This work was supported by the Human Resources Development program (No. 20204030200110 ) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry, and Energy . This work was supported by the UAV High Efficiency Turbine Research Center program of Defense Acquisition Program Administration and Agency for Defense Development and also partially supported by the Hanwha Aerospace.

Publisher Copyright:
© 2021 Elsevier Ltd

All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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