PSI - Issue 20

Tatiana Fesenko et al. / Procedia Structural Integrity 20 (2019) 284–293

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Tatiana Fesenkoet al. / Structural Integrity Procedia 00 (2019) 000–000

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elements are taken in a stationary configuration. 3. Calculation results

Dynamic problem (1) is solved taking into account expressions (46, 49, 53). Fig. 2 shows oscillation amplitudes dependence for the middle tube from the velocity of cross flow, amplitudes are presented for different (distances between tubes ) intertubular distances only at vortex excitation (dotted lines) and with a hydrodynamic connection between the tubes of bundle (solid lines). The results show that it is possible to determine the critical flow velocity for a definite bundle. For "close" bundles, hydroelastic instability occurs at lower flow velocities.

Fig. 2. The dependence of oscillation amplitudes for the bundle cells with different intertubular steps on the velocity with (solid line) and without (dashed line) hydrodynamic relationship

Conclusions Proposed mathematical model of power equipment tube bundles oscillations makes it possible to determine appearance of hydroelastic instability regime for bundles with established parameters and carry out efficient testing of the designed structure. Based on obtained by authors hydrodynamic connections matrices, tubes amplitude frequency characteristics depending on structural and operational characteristics of tube bundles were studied. These data make it possible to further heat exchangers designs optimization. References Nikolaev, N.Ya., Smirnov, L.V., 1985. Mathematical model of hydroelastic vibrations excitation of elastic tubes cross bundle. Applied problems of strength and plasticity. Statics and dynamics of deformable systems. Proceedings of Gorky University, 118-126. Fesenko, T.N., Fursov, V.G., 2005. Forced oscillation of tube bundles in liguid cross-flow. Vibration problems ICOVP, Istanbul, 205-212.