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The work is d to improving methods for calculating the cooling system of a microturbine with a rotor on air bearings. When designing gas turbines, it is important to integrate gas-dynamic calculations with thermal finite-element calculations. In practice, the conjugation of temperature fields in solids and liquids, as well as the transfer of thermal loads between the media are carried out using several approaches: direct, non-conjugate and sequential coupled. Numerical simulation of the coupled heat transfer in a cavity formed by the gap between the rotor and stator is carried out. To calculate the flow characteristics of a viscous compressible fluid and heat transfer. The degree of influence on the results of the type of turbulence model used, the influence of taking into account the conjugate heat transfer, is studied. The effect of the mass flow rate of the cooler on the flow structure and the cooling efficiency of the walls of the rotor and stator is investigated. A comparison is made with experimental data. Numerical experiments have shown that in typical cases the flow in the cavity is turbulent. The cooling efficiency has a limit on the flow rate of the cooler. The temperature distribution along the length of the rotor has a noticeable minimum in the region of the middle of the length of the rotor. The significance of the obtained results lies in the fact that the choice of the turbulence model weakly affects the calculation results and taking into account the conjugate nature of heat transfer is necessary.

The purpose of this paper is to estimate the possibility of technical use of the 110 kV voltage lines (OPL) for the interconnection of the power systems of the Republic of Moldova and Romania, taking into account in the unified power system regime, which includes the power system of the CIS countries, of Moldova, Romania, Ukraine and other countries in the region. In the calculation scheme of the permanent synchronous regime of the integrated system, the interconnection zone of the Moldovan and Romanian systems was highlighted for the lines of 110 kV: Stanca-Costeşti, Ţuţora (Fai) - Ungheni and Hushi-Cioara. Transformer phase difference angle adjustment devices have been introduced in the 110 kV OPL to provide the bidirectional power shift regime. In the existing topology of electricity networks, power flows at the power system interface are directed from the Republic of Moldova to Romania. Changing the direction of the power flows is possible through the 110 kV OPL A when equipped with phase shift devices. The results of the calculations of the permanent regime have demonstrated the possibility of achieving the reciprocal power exchange regime between the interconnected power systems by adjusting the phase difference angle. It was shown the possibility of stable operation when using 110 kV overhead power lines as interconnection lines of the Moldovan and Romanian power systems. The issue of interconnection through the 110 kV lines is complex and requires an individual approach to how to achieve it.