Theoretical and Experimental Study on the Stochastic Characteristics of Fluid Elastic Instability of Condenser Tubes

摘要

In this paper, the fluid elastic instability mechanism models of tube rows and tube arrays of condensers have been made. It is considered that each vibration mode of one tube is fluid dynamically coupled to all the modes of adjacent tubes. Mechanism modeling of single tube has been accomplished, and the vibration characteristics of single tube in all-support-effective state are calculated using analytic method. The Assumed Mode Method is used in calculating characteristics of other supporting states, the results can be substituted directly into the critical velocity computational formula to get the critical velocity of cross flow. And the stochastic characteristics results are obtained by using the manufacturing errors and theoretical gap between tubes and support baffles. All the analyses above are united to calculate the probabilities of fluid elastic instability happening to single tube of every possible supporting states so that the holistic instability can be evaluated. The tube bundle simulation experiment found the characteristics of single tube in different supporting states, and explored some rules of the FIV of the tube, pipe sound pulsation and acoustic resonance.