Authors & Affiliations
Samolysov A.V., Marchevskaya O.A., Kaplunov S.M.
Federal Budget-funded Institute for Machine Science named after A.A. Blagonravov of the Russian Academy of Sciences IMASH RAS), Moscow, Russia
Marczewska O.A. – student, ederal state budgetary institution of science Institute of machine science n.a. A.A. Blagonravova of the Russian Academy of Sciences.
Kaplunov S.M. – Professor, Dr. Sci. (Tech.), Federal state budgetary institution of science Institute of machine science n.a. A.A. Blagonravova of the Russian Academy of Sciences.
On basis of described in literature experimental data the main excitation mechanisms of tube bundles vibration were analyzed and for the most dangerous excitation mechanism – hydroelastic – the reason of its appearance was determined: it is the stability loss of unperturbed tubes position caused by separated tube bundle flow in terms of their close location. It was proved that tubes vibrations excit ation fluid-elastic mechanism nature requires separated tubes flow consideration because excluding separated flow mechanism, we obtain expression for the critical speed which shows aperiodic stability loss. While experimentally we can observe not aperiodic but oscillatory stability loss with freque ncy close to individual tube natural frequency. For work tasks solving numerical experiments were chosen as the most cost-effective and modern methods of multicomponent systems flow processes research – vortex methods which allow with engineering precision to reproduce adequately the nature of physical processes. The article describes method of tubes bundle critical flow velocity determination development by matrix of hydrodynamic interaction as the main "bundle – liquid system characteristic identification. Matrix of hydrodynamic interaction for a bundle with given tub es arrangement in cross section may be determined by numerical experiment. Limited research in the framework of twodimensional section hypothesis, it is possible not to specify the form of flexural tubes vibrations, but analyze distributed hydrodynamic forces in an arbitrary bundle cross section. In numerical experiment it is enough to consider twodimensional problem of circular profiles system flow, when each profile can oscillate by a given law. General scheme of numerical experiment allowing to determine matrix of hydrodynamic interaction elements for a particular bundle is shown below.
Hydroelastic excitation, stability loss, critical flow velocity, separated flow, hydrodynamic interaction matrix, vortex methods
1. Kaplunov S.M., Valles N.G., Samolisov A.V., Marchevskaya O.A. Opredelenie kriticheskikh parametrov obtekaniya puchka trub metodom chislennogo eksperimenta [Determination of critical tube bundle flow parameter by numerical experiment method]. Teploenergetika – Thermal Engineering, 2015, no. 8, pp. 57-62.
2. Guvernjuk S.V., Dinnikova G.Ya. Modelirovanie obtekaniya koleblyushchegosya profilya meto-dom vyazkikh vikhrevykh domenov [Flow simulation around vibrating profile by viscous vortex domains method]. Izvestiya RAN. Seriya: Mekhanika Zhidkosti i Gaza – Journal of Russian Academy of Sceinces. Fluid Dynamics, 2007, no. 1, pp. 3-14.
3. Alyamovskiy M.I. Raschet avtokolebaniy trub teploobmennykh apparatov. [Tubes self-oscillations in heat exchangers]. Energomashinostroenie-Power Plant Engineering, 1975, no. 3, pp. 33-35.
4. Connors H.J. Flow-induced vibration and wear of steam generator tubes. Nuclear technology, 1981, vol. 55, no. 2, pp. 311-334.