Detailed Analysis of the Thermal Wall Heat Load in Annular Combustors

1999 ◽  
Author(s):  
Werner Krebs ◽  
Günther Walz ◽  
Stefan Hoffmann ◽  
Hans Judith
Keyword(s):  
Heat Flux ◽  
Combustion Chamber ◽  
Heat Load ◽  
Thermal Power ◽  
Wall Heat Flux ◽  
Navier Stokes ◽  
Ceramic Tiles ◽  
Combustion Gases ◽  
Annular Combustor ◽  
Cooling Air

A detailed thermal analysis involving both measurements and calculations has been carried out in order to determine the wall heal load and to optimize the amount of cooling air for an annular combustor. In calculations, the convective wall heat flux has been detemined by application of a 3D Navier-Stokes Code. Furthermore, the radiation exchange between the hot combustion gases and the liner has been calculated using a multidimensional spectral approach. Although a quite high thermal power density is found within the combustion chamber the wall heat load is at a low level. Values are well below 80 kW/m2, due to the application of ceramic tiles which have a low thermal conductivity. The wall heat load is dominated by radiation emitted in the lower gas radiation bands (λ < 2.9 μm). The convective wall heat flux is nearly balanced out by the sealing air which is discharged through gaps between the ceramic tiles. The cooling effect of the sealing air, however, is strongly influenced by the 3D near wall flow field in the combustion chamber.

Impact of Radiation on the Wall Heat Load at a Test Bench Gas Turbine Combustion Chamber: Measurements and CFD Simulation

2007 ◽  
Author(s):  
R. Dannecker ◽  
K.-U. Schildmacher ◽  
B. Noll ◽  
R. Koch ◽  
M. Hase ◽  
...  
Keyword(s):  
Heat Flux ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Heat Load ◽  
Thermal Design ◽  
Wall Heat Flux ◽  
Radiative Properties ◽  
Numerical Work ◽  
Gas Turbine Combustion ◽  
The Impact

Experimental and numerical work has been carried out to determine the wall heat load at the liner structure of a model gas turbine combustion chamber. Measured cross-sectional profiles of the velocity and temperature field inside the chamber could be used to validate various CFD calculations of the combustion flow. It turned out that only a special treatment of the thermal boundary conditions at all liner walls would actually lead to appropriate values of the wall heat flux. Radiation modeling included two radiative properties models (SG single gray gas and WSSG weighted sum of gray gases) and three radiation transport models (P1, DT discrete transfer, MC Monte Carlo). The performance of the WSGG model has been assessed with charts and the impact of the radiation on the liner wall temperature distribution has been studied. The experimental values are matched within 3% deviation with the best combination of transport and radiation property models. The radiation contributes to 20-30% of the total wall heat flux. The present approach enables Siemens PG to access the thermal design of combustors more precisely.

scholarly journals Wall heat flux measurements in a GO2/GH2 heat-sink combustion chamber

2018 ◽  
Vol 13 (1) ◽  
pp. JTST0016-JTST0016 ◽  
Author(s):  
Taiping WANG ◽  
Bing SUN ◽  
Jixin XIANG ◽  
Di LIU
Keyword(s):  
Heat Flux ◽  
Combustion Chamber ◽  
Heat Sink ◽  
Wall Heat Flux ◽  
Flux Measurements

Transfer Function Measurements on a Swirl Stabilized Premix Burner in an Annular Combustion Chamber

2004 ◽  
Author(s):  
Klaas Kunze ◽  
Christoph Hirsch ◽  
Thomas Sattelmayer
Keyword(s):  
Transfer Function ◽  
Heat Release ◽  
Combustion Chamber ◽  
Acoustic Waves ◽  
Velocity Fluctuation ◽  
Transfer Functions ◽  
Flow Direction ◽  
Near Field ◽  
Thermal Power ◽  
Annular Combustor

A generic swirl stabilized premix burner for natural gas is experimentally investigated in both a single burner test rig and in an annular combustion chamber. Flame transfer functions are measured relating the fluctuation of the flame heat release to the axial velocity fluctuation at the burner outlet. The OH-chemiluminescence signal of the flame, captured with a photomultiplier tube, is taken as an estimate for flame heat release, whereas the velocity fluctuation is measured with a hot wire probe. As integral measurements of the entire flame reveal important differences between the single burner and the annular combustor, locally resolved measurements are performed observing slices of the flame that are perpendicular to the main flow direction at a variable distance from the burner outlet. In both the single and the annular combustor a near field and a far field of the dynamic flame behavior can be distinguished. The annular combustor flame has a larger near field than the single combustor flame and a different shape in the presence of circumferential acoustic waves. Variation of swirl, thermal power and mass flow and comparison of the steady state heat release distribution within the flames lead to the result that the effective swirl in the annular combustor is lower than for the identical burner in the single burner combustor. When the difference in swirl is compensated for by modifying the burner configuration in the annular combustion chamber the flame transfer function is still not equal to the single combustor flame. The remaining difference can be attributed to the circumferential acoustic waves in the annular combustor which influence the flame shape.

scholarly journals Simulation of the GOx/GCH4 Multi-Element Combustor Including the Effects of Radiation and Algebraic Variable Turbulent Prandtl Approaches

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5009
Author(s):  
Evgenij Strokach ◽  
Igor Borovik ◽  
Oscar Haidn
Keyword(s):  
Heat Flux ◽  
Turbulence Modeling ◽  
Stokes Equations ◽  
Reynolds Stress Model ◽  
Reaction Scheme ◽  
Wall Heat Flux ◽  
Navier Stokes ◽  
Good Representation ◽  
Gaseous Oxygen ◽  
Spectral Models

Multi-element thrusters operating with gaseous oxygen (GOX) and methane (GCH4) have been numerically studied and the results were compared to test data from the Technical University of Munich (TUM). A 3D Reynolds Averaged Navier–Stokes Equations (RANS) approach using a 60° sector as a simulation domain was used for the studies. The primary goals were to examine the effect of the turbulent Prandtl number approximations including local algebraic approaches and to study the influence of radiative heat transfer (RHT). Additionally, the dependence of the results on turbulence modeling was studied. Finally, an adiabatic flamelet approach was compared to an Eddy-Dissipation approach by applying an enhanced global reaction scheme. The normalized and absolute pressures, the integral and segment averaged heat flux were taken as an experimental reference. The results of the different modeling approaches were discussed, and the best performing models were chosen. It was found that compared to other discussed approaches, the BaseLine Explicit Algebraic Reynolds Stress Model (BSL EARSM) provided more physical behavior in terms of mixing, and the adiabatic flamelet was more relevant for combustion. The effect of thermal radiation on the wall heat flux (WHF) was high and was strongly affected by spectral models and wall thermal emissivity. The obtained results showed good agreement with the experimental data, having a small underestimation for pressures of around 2.9% and a good representation of the integral wall heat flux.

scholarly journals The Effect of Inert Fuel Compounds on Flame Characteristics

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 262
Author(s):  
Igor Hudák ◽  
Pavel Skryja ◽  
Jiří Bojanovský ◽  
Zdeněk Jegla ◽  
Martin Krňávek
Keyword(s):  
Heat Flux ◽  
Combustion Chamber ◽  
Alternative Fuels ◽  
Thermal Power ◽  
Hydrocarbon Fuel ◽  
Inert Gases ◽  
Inert Gas ◽  
Nox Emissions ◽  
Testing Facility ◽  
Fuel Burner

To describe the effects of inert compounds in gaseous fuel, experiments on three different process burners (staged fuel burner, staged air burner, and low-calorific burner) were carried out. The tested burners are commercially available, but they were specially designed for experimental usage. Tests were carried out in the semi-industrial burner testing facility to investigate the influence of inert gases on the flame characteristics, emissions, and heat flux to the combustion chamber wall. Natural gas was used as a reference fuel, and, during all tests, thermal power of 500 kW was maintained. To simulate the combustion of alternative fuels with lower LHV, N2 and CO2 were used as diluents. The inert gas in the hydrocarbon fuel at certain conditions can lower NOx emissions (up to 80%) and increase heat flux (up to 5%). Once incombustible compounds are present in the fuel, the higher amount of fuel flowing through nozzles affects the flow in the combustion chamber by increasing the Reynolds number. This can change the flame pattern and temperature field, and it can be both positive and negative, depending on actual conditions.

scholarly journals Large-Eddy Simulations for the Wall Heat Flux Prediction of a Film-Cooled Single-Element Combustion Chamber

2020 ◽  
pp. 223-234
Author(s):  
R. Olmeda ◽  
P. Breda ◽  
C. Stemmer ◽  
M. Pfitzner
Keyword(s):  
Heat Flux ◽  
Combustion Chamber ◽  
Film Cooling ◽  
Structural Integrity ◽  
Cooling System ◽  
Rocket Engine ◽  
Large Eddy Simulations ◽  
Wall Heat Flux ◽  
Single Element ◽  
Large Eddy

Abstract In order for modern launcher engines to work at their optimum, film cooling can be used to preserve the structural integrity of the combustion chamber. The analysis of this cooling system by means of CFD is complex due to the extreme physical conditions and effects like turbulent fluctuations damping and recombination processes in the boundary layer which locally change the transport properties of the fluid. The combustion phenomena are modeled by means of Flamelet tables taking into account the enthalpy loss in the proximity of the chamber walls. In this work, Large-Eddy Simulations of a single-element combustion chamber experimentally investigated at the Technical University of Munich are carried out at cooled and non-cooled conditions. Compared with the experiment, the LES shows improved results with respect to RANS simulations published. The influence of wall roughness on the wall heat flux is also studied, as it plays an important role for the lifespan of a rocket engine combustors.

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