ISSN 1991-2927
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 V. Kovalnogov, R. Fedorov, L. Khakhaleva, A. Chukalin
 Mathematical Modeling and Numerical Analysis of Thermal Protection Effectiveness With Hemispherical Damping Cavities The gas turbine engine performance improvement is linked inextricably with the increase of the intensity of dynamic, aeromechanical and thermal processes, which, in turn, requires the development of systems and devices allowing to protect the most loaded equipment components. The most effective ways to protect surfaces from overheating are a convective cooling; the absorption and accumulation of heat by condensed substances; the cooling that operates on mass transfer principle; the radiation and electromagnetic cooling; heat-shielding coatings. One of the most effective ways to protect surfaces from overheating is a thermal protection in the form of film-like surface cooling based on the mass-transfer surface-cooling principle. This method is widely distributed and it proved to be effective. The paper considers the possibility of improving this method of cooling due to the impact on the boundary layer with hemispherical damping cavities behind the injection section of the cooler. A mathematical model is proposed, the numerical study of the thermal protection effectiveness by the use of hemispherical damping cavities is carried out. The possibility of a significant decrease of the turbulent heat exchange in the boundary layer and of the efficiency improvement of the thermal surface protection of ? by0.06 due to the use of hemispherical damping cavities has been established. The proposed method of thermal protection intensifying and numerical analysis of its efficiency will improve the gas turbine engines that are available for different applications of domestic industry for example in power generation sector, aircraft engineering as well as in shipbuilding.Hemispherical damping cavities, turbulent transport, mathematical modeling, boundary layer, thermal protection.
 2018_ 4

Sections: Mathematical modeling

Subjects: Mathematical modeling.

 V. Kovalnogov, D. Generalov, A. Chukalin, R. Fedorov, A. Plekhanova
 New Engineering Solutions Based on Mathematical Modelling of the Turbine Blade System The article deals with a method for studying the thermal state of turbomachine blades and a numerical investigation method taking into account the phenomenon of gas-dynamic temperature stratification. The authors consider the possibility of increasing the efficiency of cooling turbine blades due to the phenomenon of gas-dynamic temperature stratification, the possibility of improving the accuracy of the calculated forecasting of the thermal state of the blades by obtaining reliable data by developing a mathematical model and a unique software and information complex for modelling.Mathematical modelling, numerical methods, thermal protection, film cooling, software and information complex, dispersed flow.
 2017_ 3

Sections: Mathematical modeling

Subjects: Mathematical modeling.

 V. Kovalnogov, A. Chukalin, L. Khakhaleva, R. Fedorov, A. Plekhanova
 Researching the Influence of the Number of Damping Cavities on Frictional Resistance of Turbulent Flow As a result of experimental and numerical research of turbulent flow with effects on the basis of the modified model of the Prandtl mixing length with the use of pressure pulsation analysis, the structure and resistance of turbulent flow frictional resistance were calculated. The developed model of turbulent exchange and the calculation method allow to take adequately into account the features of the metabolic processes in the presence of damping cavities and predict the frictional resistance with the help of preliminary calculation. The possibility of reduction of the frictional resistance coefficient of a turbulent flow to 35 % was experimentally set with the use of damping cavities. The generalization of the influence of the amount of damping cavities on the frictional resistance was carried out.Damping cavities, mathematical modelling, frictional resistance, turbulent flow.
 2017_ 1

Sections: Mathematical modeling

Subjects: Mathematical modeling.

 A. Zolotov, V. Kovalnogov, M. Kornilova
 Modeling and Researching the Technique of Thermal Protection of Turbomachines Blades With the Use of Gas-dynamic Temperature Stratification Raising the initial temperature and pressure of the working fluid is one of the simplest and most effective ways of improving fuel efficiency and reducing metal consumption of turbines. Traditional technology of turbine blades production is quite cost and time consuming in production. Therefore, their creation requires the use of mathematical models which serve as a tool for analysis, improvement and selecting the most promising solutions of the refrigeration and increase of the prediction accuracy at the design stage of their effectiveness. Mathematical modeling of the thermal state is widely used in the creation of modern gas turbines [1]. An important objective is the numerical simulation of the spatial flow of the heat transfer in subsonic and transonic lattices. In order to create effective ways of thermal protection, it is necessary to know the distribution of nonstationary temperature fields on the surface and in the body of the scapula. For this purpose, the heat flows from the gas to the blades must be accurately determined taking into account the impact of the mode of flow, thermals, pressure gradient, and other factors [2]. In the paper, the proposed mathematical model and method of numerical investigation of the thermal state of blades of turbomachines streamlined by a supersonic dispersed flow with regard to the phenomenon of gas-dynamic temperature stratification was proposed. With the aim to increase the accuracy of the settlement prediction of the thermal state of blades due to obtaining reliable data as well as improve the efficiency of cooling systems to increase the service life of the blades, the authors have developed the program-informational complex which will take into account the results of studies of gas-dynamic processes in high- speed, disperse flows including the phenomenon of gas-dynamic temperature stratification carried out at the Department of Heat Power Engineering at Ulyanovsk State Technical University.Mathematical modeling, numerical methods, thermal protection, convective-film cooling, software and information complex, dispersed flow, gas-dynamic temperature stratification.
 2015_ 4

Sections: Mathematical modeling

Subjects: Mathematical modeling, Computer-aided engineering.

 V. Kovalnogov, R. Fedorov, L. Khakhaleva, A. Chukalin
 Mathematical Modeling and Numerical Analysis of Flow Laminarization in a Perforated Tube With Damping Cavities The authors have experimentally established the possibility of the partial turbulent flow laminarization in a perforated tube with damping cavities which leads to reduction of up to 35% of frictional resistance. The effect of the number of perforations in the damping cavity on the velocity profile and the frictional resistance has been revealed. The model of turbulent transfer in a boundary layer near the perforated surface with damping cavities and the method of calculating the flow pattern and frictional resistance were proposed. Flow laminarization manifested itself as the decrease of turbulent transfer intensity in the boundary layer due to external or internal influences plays an important role in engineering. Apparently, for the first time the possibility of a reverse transition of a turbulent flow in a laminarization one under the influence of a negative longitudinal pressure gradient was noted in the article [1]. Further researches overviewed in the paper [2] have demonstrated that laminarization in flows with negative longitudinal pressure gradient is accompanied by a substantial (up to 35 ... 50%) decrease of the intensity of heat and a simultaneous increase in the frictional resistance. The model of laminarization in the streams with different influences proposed in the paper [2] has allowed to predict the possibility of its implementation and anear perforated surface with damping cavities. As this takes place, in contrast to the laminarization under the influence of a negative longitudinal pressure gradient there must be a reduction of both the intensity of heat transfer and friction resistance. The purposes of this work are experimental investigation of frictional resistance in the perforated tube with damping cavities with a different number of perforations, the development of turbulent transfer process models and the calculation method of friction resistance.Perforated pipe, a damping cavity, turbulent transfer, mathematical modeling, friction resistance.
 2015_ 4

Sections: Mathematical modeling

Subjects: Mathematical modeling.

 V. Kovalnogov, R. Fedorov, E. Tcvetova, A. Petrov
 Mathematical Modeling and Investigation of Effectiveness of Gas-dynamic Temperature Stratification in Disperse Flow The article gives a method and results of a numerical investigation of the process of gas-dynamic temperature stratification in disperse flow. It justifies an opportunity to significantly increase the efficiency of temperature stratification of dispersed flow via heat transfer surface enhancers made on the working surface of the subsonic flow path.Gas-dynamic temperature stratification, disperse flow, supersonic flow, heat transfer enhancement.
 2013_ 1

Sections: Mathematical modeling, calculi of approximations and software systems

Subjects: Mathematical modeling.

 V. Kovalnogov, Y. Khakhalev
 Mathematical Modeling of Turbulent Flow Based on Analysis of Fractal Dimension of Pressure Fluctuations The article defines the fractal dimension of turbulent pressure fluctuations on the basis of theoretical and experimental studies. It offers a mathematical model for turbulence based on the fractal characteristics of pulsations.Boundary layer, pressure fluctuations, turbulent flow, model, chaos, fractal characteristics.
 2013_ 1

Sections: Mathematical modeling, calculi of approximations and software systems

Subjects: Mathematical modeling.

 V. Kovalnogov, A. Korolev, R. Fedorov
 Mathematical Modeling and Numerical Analysis of Efficiency of Surface Film Coolingin Supersonic Flow Dispersion The article provides a mathematical model and results of computational investigations into the effect of the inertial deposition of particles of condensed phase on the efficiency of film cooling of surface in supersonic flow dispersion. The authors determine a possible realization of Leontyev paradox in adiabatic surface area, which consists in achieving protected surface temperature less than that of cooler in permeable area of protection creation.Boundary layer, thermal protection, mist flow, modeling.
 2012_ 4

Sections: Mathematical modeling, calculi of approximations and software systems

Subjects: Mathematical modeling.

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