안쪽축이 회전하는 환형관내 유동연구

A Study on the Flows in a Concentric Annulus with rotating inner cylinder

  • 김영주 (성균관대학교 기계공학부 대학원) ;
  • 우남섭 (성균관대학교 기계공학부 대학원) ;
  • 권혁정 (성균관대학교 기계공학부 대학원) ;
  • 황영규 (성균관대학교 기계공학부)
  • 발행 : 2002.08.01

초록

The present experimental and numerical investigations are performed for the characteristics of transitional flow in a concentric annulus with a diameter ratio of 0.52, whose outer cylinder is stationary and inner one rotating. The flow field of an annulus has been numerically solved using a finite volume method. The pressure losses and Skin-friction coefficients have been measured for the fully developed flow of water and $0.2{\%}$ aqueous solution of sodium carboximethy1 cellulose (CMC), respectively at inner cylinder rotational speed of $0{\~}600rpm$. The transitional flow has been examined by the measurement of pressure losses to reveal the relation of the Reynolds and Rossby numbers with the skin-friction coefficients. The occurrence of transition has been checked by the gradient changes of pressure losses and skin-friction coefficients with respect to the Reynolds numbers. Consequently the critical(axial-flow) Reynolds number decreases as the rotational speed increases. Thus, the rotation of inner cylinder promotes the early occurrence of transition due to the onset of Taylor vortices.

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