The results of the current study presented the hydrodynamics and heat transfer features occur in the pipe systems of the thermal-hydraulic various elements of the ship nuclear power installations. A comparative analysis of the turbulent models choice, their approbation on typical elements of the curved pipelines, and comparison of the calculation results with experimental data were fulfilled. The conditions of the swirl flow crisis were determined on base of obtained results of theoretical studies and comparison with experimental data. The mechanism of occurrence of acoustic oscillations generated by large-scale vortex structures and causes of cyclic thermal loads were identified. The fundamental nature of the research, the use of the thermodynamic approach and the conclusions of the stability theory made it possible to predict the results of numerical calculations.

Conducted analytical studies have shown that in complex geometry channels with three-dimensional curvature, and a variable cross-section area, the conditions leading to large-scale vortex formation and swirl flow. In this case, not only the mode of swirl flow can be implemented, but also the effect of locking the flow due to the crisis of the swirl flow. It is shown that the crisis of swirl flow can take place in various power, motor, chemical-technological devices and other technical devices associated with the use of high-speed swirl flows of liquids or gases. A characteristic feature of such devices is the presence of large pressure losses required for the organization of flow swirling in channels of complex geometry. In the present paper, the manifestation of the swirl flow crisis is considered on the example of modeling the processes of hydrodynamics and heat exchange in the channels of an icebreaker steam generating installation.

The mechanisms of generation of stable large-scale eddies and flow swirling in complex channels of the 1st and 2nd circuits of transport nuclear power plants (NPP) are revealed. An analysis is given of the influence of vortex formation and flow swirling processes on failures in NPP systems. It is shown that with a complex geometry of the channels of the pipe systems of the thermohydraulic tract and the reactor plant (RP), the unauthorized swirl arising in certain dynamic modes can lead to the effect of blocking the flow caused by the swirl flow crisis. It has been established that the phenomenon of the crisis is accompanied by the generation of low-frequency acoustic vibrations and large pressure losses required to form a recirculation flow zone, which prevents the flow of fluids in complex channels of the nuclear power plant. In the presented work, the manifestation of a swirling flow crisis is considered by examples of modeling the processes of hydrodynamics and heat transfer in the channels of steam generators and the pressure compensation system of transport nuclear power plants. It is shown that the generation of stable vortex formations in the elements of the NPP equipment of the integral type can be directly related to the mechanism of excitation of hazardous vibroresonance effects. Methods for improving the design of pipe systems of steam generating plants are proposed to increase their thermal-hydraulic efficiency and vibration resistance.

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