Hydroinertia gas bearing system to achieve 470 m/s tip speed of 10 mm-diameter impellers

Shuji Tanaka, Masayoshi Esashi, Kousuke Isomura, Kousuke Hikichi, Yuki Endo, Shinichi Togo

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


A microbearing tester driven by an air turbine of 10 mm diameter has been developed, and successfully used to test hydroinertia gas bearings with a shaft of 4 mm diameter. The effects of bearing gas pressure conditions and bearing length to diameter ratio (L/D) on the maximum achievable rotation speed were investigated. The maximum rotation speed of 890,000 rpm, which corresponds to the DN number (the product of a shaft diameter in millimeter and a rotation speed in rpm) of 3,560,000, was achieved. At 890,000 rpm, the tip speed of the turbine reaches approximately 470 m/s. Using the bearing system developed, the turbo components of a 100 W class gas turbine and an air pump for 1 kW class fuel cells can be tested.

Original languageEnglish
Pages (from-to)655-659
Number of pages5
JournalJournal of Tribology
Issue number3
Publication statusPublished - 2007 Jul 1


  • High-speed bearing
  • Hydroinertia gas bearing
  • Microturbomachinery
  • Turbine

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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