Dissertation is devoted to solving an important scientific and technical task of improving the cooling systems of gas turbines by further developing the methods of hydraulic and thermal calculation of the channels of the cooling system of gas turbines. To study the structure and flow properties of these elements, to obtain the dependences describing this flow.
The analysis of scientific and technical literature devoted to the design of cooling systems for gas turbine engines was carried out, in which international experience of experimental studies and computational experiments was considered, to the study of heat transfer and flow hydrodynamics in rotating elements. As a result of the analysis of the literature, it is shown that the main direction of development of efficient and reliable GTE cooling systems is to improve the accuracy of the calculation of the flow and hydraulic characteristics of the elements of the cooling system.
It is shown that the modeling of processes is influenced by the channel geometry, flow direction (centrifugal, centripetal), presence of associated flows, parameters and properties (air, oil-air) of the cooling medium. Therefore, the accuracy with which the simulation of the entire cooling system depends on the accuracy with which the individual element will be modeled.
Mathematical models of hydraulic network elements have been adapted to calculate gas turbine cooling systems, such as: a device for swirling flow, a heat exchanger, channels that are moved.
Description, theoretical bases of modeling of these elements of a hydraulic circuit, the researches carried out on the influence of the apparatus of the twist and the heat exchange apparatus on the efficiency of cooling are given, the corresponding models of cooling systems are made.
Impact study conducted of the centrifugal effect on the possibility of air supply in the cavity of the rotor of the turbine has been studied. The considered examples of air flow in cavities formed by two parallel disks with axial or radial air supply at a peripheral radius.
CFD analysis showed that, depending on the direction of air supply, the nature of the flow in the cavity is significantly changed. At radial air supply in the direction of the axis of rotation there is a non-vortex nature of the flow, with axial - vortex occurs. However, the difference in the nature of the flow almost does not affect the magnitude of the back pressure, which impedes the movement of air.
Тhe range of reliability of the results of the calculation method of the pump effect in the disk cavities of the rotors of the gas turbines is determined, namely: the ratio of the width of the cavity to the external radius of the disk does not exceed the value of 0.17, which allows us to use this method reasonably for calculations of the cooling systems.
Developed a generalized approach to the method of calculating the flow coefficients and the hydraulic resistance of elements of the cooling systems of gas turbines such as openings, thickened diaphragms, labyrinth seals, regulating the flow of cooling air, which are responsible for the reliability and economy of the cooling system.
In the calculations of the hydraulic circuit, the hydraulic resistance coefficients of each section of the circuit are used, and the experimental data are often represented by flow coefficients. Therefore, a connection is established between them using assumptions that take into account the difference between compressible and incompressible media.
On the basis of the research, justified correction for compressibility to the coefficient of hydraulic resistance of elongated diaphragms, holes, labyrinth seals, which specifies the coefficient of hydraulic resistance to 25%.
A mathematical model for calculating the bearing has been developed, approaches have been described for determining the concentration and thermodynamic characteristics of a two-phase homogeneous medium, which made it possible to include the bearing in both the hydraulic and thermal models of gas turbine cooling systems.
A method was developed for calculating the hydraulic network for the air-oil mixture, which significantly expanded the possibilities for simulating the cooling processes of the rotors and bearings of gas turbines and providing bearings with oil, which made it possible to jointly calculate the cooling system of the turbine rotor and bearings.
A study of the cooling system of the rotor of a high-temperature gas turbine was carried out using the developed calculation methods. It is esta
