Study of radiation heat transfer and the temperature state in the combustion chambers of small-size gas-turbine engines (GTEs)

In modern gas turbine engines, the blade tips and near-tip regions are exposed to high thermal loads caused by the tip leakage flow. The rotor blades are therefore carefully designed to achieve optimum work extraction at engine design conditions without failure. However, very often gas turbine engines operate outside these design conditions which might result in sudden rotor blade failure. Therefore, it is critical that the effect of such off-design turbine blade operation be understood to minimize the risk of failure and optimize rotor blade tip performance. In this study, the effect of varying the exit Mach number on the tip and near-tip heat transfer characteristics was numerically studied by solving the steady Reynolds averaged Navier Stokes (RANS) equation. The study was carried out on a highly loaded flat tip rotor blade with 1% tip gap and at exit Mach numbers of Mexit = 0.85 (Reexit = 9.75 × 105) and Mexit = 1.0 (Reexit = 1.15 × 106) with high freestream turbulence (Tu = 12%). The exit Reynolds number was based on the rotor axial chord. The numerical results provided detailed insight into the flow structure and heat transfer distribution on the tip and near-tip surfaces. On the tip surface, the heat transfer was found to generally increase with exit Mach number due to high turbulence generation in the tip gap and flow reattachment. While increase in exit Mach number generally raises he heat transfer over the whole blade surface, the increase is significantly higher on the near-tip surfaces affected by leakage vortex. Increase in exit Mach number was found to also induce strong flow relaminarization on the pressure side near-tip. On the other hand, the size of the suction surface near-tip region affected by leakage vortex was insensitive to changes in exit Mach number but significant increase in local heat transfer was noted in this region.

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Preparation, Structure, and Properties of Ni3Al and NiAl Light Powder Alloys for Aerospace

Materials Science Forum ◽

10.4028/www.scientific.net/msf.534-536.1585 ◽

2007 ◽

Vol 534-536 ◽

pp. 1585-1588 ◽

Cited By ~ 10

Author(s):

K.B. Povarova ◽

O.A. Skachkov

Keyword(s):

Gas Turbine ◽

New Technology ◽

Turbine Engines ◽

Heat Sources ◽

Gas Turbine Engines ◽

Combustion Chambers ◽

Term Operation ◽

Heat Resistant ◽

Turbine Installation

New light super-heat-resistant powder Ni3Al and NiAl-based alloys (of the Ni-Al-Mo-B, Ni-Al-Fe-La, and Ni-Al-Y2O3 systems), as well as a new technology for preparing and processing them have been developed. The density of the alloys was 7.3-7.5 and ~6 g/cm 3, respectively. The Ni3Al sheets were used to prepare shields for combustion chambers in gas-turbine engines by roomtemperature deformation; the shields are intended for the long-term operation at 1100-1200°C and for the short-term use at 1300°C. The activated NiAl powders alloyed with Fe+La were used to produce sintered complex-shape articles, such as combustion stabilizers in a jet unit of combustion chamber of the gas-turbine installation, heat sources, etc. capable of operating at t≤1500°C under low mechanical stresses. At 1100, 1300, and 1500°C, the 100-h strength of the heat-resistant NiAl- (2-7.5) vol. % Y2O3 alloys subjected to directional recrystallization is 70, 35 and ≥10 MPa, respectively. The vanes, in which the length of recrystallized grain is smaller than the vane length by a factor of 1.5-2, were manufactured from these alloys.

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High Intensity, Large Length-Scale Freestream Turbulence Generation in a Transonic Turbine Cascade

Volume 3: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30523 ◽

2002 ◽

Cited By ~ 9

Author(s):

A. C. Nix ◽

A. C. Smith ◽

T. E. Diller ◽

W. F. Ng ◽

K. A. Thole

Keyword(s):

Heat Transfer ◽

Gas Turbine ◽

High Intensity ◽

Turbine Engines ◽

Length Scale ◽

Gas Turbine Engines ◽

Freestream Turbulence ◽

Large Length ◽

Scale Turbulence ◽

Large Length Scale

Heat transfer predictions in gas turbine engines have focused on cooling techniques and on the effects of various flow phenomena. The effects of wakes, passing shock waves and freestream turbulence have all been of primary interest to researchers. The focus of the work presented in this paper is to develop a turbulence grid capable of generating high intensity, large-scale turbulence for use in experimental heat transfer measurements in a transonic facility. The grid is desired to produce freestream turbulence characteristic of the flow exiting the combustor of advanced gas turbine engines. A number of techniques are discussed in this paper to generate high intensity, large length-scale turbulence for a transonic facility. Ultimately, the passive grid design chosen is capable of producing freestream turbulence with intensity of approximately 10–12% near the entrance of the cascade passages with an integral length-scale of 2 cm.

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Increasing the Ecological Efficiency of Combustion Chambers in Gas-Turbine Engines Using Low-Current Plasmochemical Stabilizers

NTU KhPI Bulletin Power and heat engineering processes and equipment ◽

10.20998/2078-774x.2017.09.04 ◽

2017 ◽

Vol 0 (9) ◽

Author(s):

Sergei Ivanovich Serbin ◽

Artem Viktorovich Kozlovskyi

Keyword(s):

Gas Turbine ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Ecological Efficiency ◽

Combustion Chambers

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Design and development of combustion chambers for gas turbine engines based on calculations of various levels of complexity

VESTNIK of the Samara State Aerospace University ◽

10.18287/2541-7533-2021-20-3-7-23 ◽

2021 ◽

Vol 20 (3) ◽

pp. 7-23

Author(s):

Y. B. Aleksandrov ◽

T. D. Nguyen ◽

B. G. Mingazov

Keyword(s):

Combustion Chamber ◽

Gas Turbine ◽

Gas Flow ◽

Combustion Process ◽

Three Dimensional ◽

Numerical Calculations ◽

Turbine Engines ◽

Gas Turbine Engines ◽

Combustion Chambers ◽

Flame Tube

The article proposes a method for designing combustion chambers for gas turbine engines based on a combination of the use of calculations in a one-dimensional and three-dimensional formulation of the problem. This technique allows you to quickly design at the initial stage of creating and development of the existing combustion chambers using simplified calculation algorithms. At the final stage, detailed calculations are carried out using three-dimensional numerical calculations. The method includes hydraulic calculations, on the basis of which the distribution of the air flow passing through the main elements of the combustion chamber is determined. Then, the mixing of the gas flow downstream of the flame tube head and the air passing through the holes in the flame tube is determined. The mixing quality determines the distribution of local mixture compositions along the length of the flame tube. The calculation of the combustion process is carried out with the determination of the combustion efficiency, temperature, concentrations of harmful substances and other parameters. The proposed method is tested drawing on the example of a combustion chamber of the cannular type. The results of numerical calculations, experimental data and values obtained using the proposed method for various operating modes of the engine are compared.

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