시뮬레이션에 의한 유체 유동 파이프 계의 곡관부의 각도 변화에 따른 고유진동수 고찰

A Simulation for the Natural Frequencies of Curved Pipes Containing Fluid Flow with Various Elbow Angles

  • 최명진 (경희대학교 기계산업시스템공학부) ;
  • 장승호 (경희대학교 기계산업시스템공학부)
  • 발행 : 2001.03.01

초록

To investigate the natural frequencies of curved piping systems with various elbow angles conveying flow fluid, a simulation is performed considering Initial tension due to the inside fluid. The system is analyzed by finite element method utilizing straight beam element. Elbow part is meshed using 4 elements, and the initial tension is considered by inserting equivalent terms into the stiffness matrix. Without considering the initial tension, the system becomes unstable, that is, the fundamental natural frequency approaches to zero value fast, as the flow velocity reaches critical value. With the initial tension terms, the system becomes stable where there is no abrupt decrease of the fundamental natural frequency. The change rate of the natural frequency with respect to the flow velocity reduces. As elbow angle increases, the system becomes stiffer, then around 150 degrees of the elbow angle the natural frequency has the largest value, the value decreases after the angle of the largest natural frequency. When angle is between 170 degrees and 179 degrees, the natural frequency is very sensitive. This means that small change of angle results in great change of natural frequency, which is expected to be utilized in the control of the natural frequency of the piping system conveying flow fluid.

키워드

참고문헌

  1. Journal of Applied Mechanics v.19 Bending Vibration of a Pipe Line containing Flowing Fluid Housner, G.H.
  2. Journal of Applied Mechanics v.19 Dynamic Vibration of a Pipe Line containing Flowing Fluid Benjamin, T.B.
  3. Proc. of Roy. Soc.(London), Ser. v.A293 Unstable Oscillation of Tubular Cantilevers conveying Fluid-I Theory Gregory, R.W.;M.P. Paidousssis
  4. Proc. of Roy. Soc.(London), Ser. v.A293 Unstable Oscillation of Tubular Cantilevers conveying Fluid-Ⅱ Theory Gregory, R.W.;M.P. Paidousssis
  5. Journal of Applied Mechanics v.40 Out of Plane Vibration and Stablity of Curved Tubes conveying Fluid Chen, S.S.
  6. Journal of Applied Mechanics v.41 Effenct of Initial Forces on the Hydroelastic Vibration and Stability of Plannar Curved Tubes Hill, J.L.;C.G. Davis
  7. Journal of the Engineering Mechanics Divison, Proceedings of the American Society of Civil Engineers Nonconservative Stablity by Finite Elements Mote, C.D.
  8. Journal of Sound and Vibration v.93 Vibration Analysis of Straight and Curved Tubes Conveying Fluid by Means of Straight Beam Finite Element Kohli, A.K.;B.C. Nakra
  9. 박사학위 논문, 경희대학교 전달행렬법을 이용한 파이프 계의 유체-유발 진동 및 동적거동에 관한 연구 이동명
  10. 석사학위논문, 경희대학교 내무 유체를 포함한 굴곡파이프의 지지점 변화에 따른 동적거동 해석에 관한 연구 박현용
  11. 석사학위논문, 경희대학교 유체의 속도와 압력을 고려한 파이프 계의 자유진동해석 김재영
  12. Design of Plping System Kellogg, M.