A Flow Network Combustor Model Applying Reduced Mechanisms

2012 ◽  
Author(s):  
Sebastian Maidhof
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Chemical Reactor ◽  
Wall Heat Transfer ◽  
Computational Tool ◽  
Flow Network ◽  
Experimental Values ◽  
Reactor Models

A computational tool that combines a flow network solver with both 1D wall heat transfer and with chemical reactor models applying reduced mechanisms is presented. The model is applied to the combustion chamber of a 75kW gas turbine and wall temperatures and emissions of CO are compared with experimental values.

Chemical Kinetic Analysis of a Flameless Gas Turbine Combustor

2008 ◽  
Author(s):  
G. Arvind Rao ◽  
Yeshayahou Levy ◽  
Ephraim J. Gutmark
Keyword(s):  
Combustion Chamber ◽  
Kinetic Analysis ◽  
Gas Turbine ◽  
Flame Temperature ◽  
Plug Flow ◽  
Combustion Process ◽  
Chemical Reactor ◽  
Chemical Kinetic ◽  
Combustion Regime ◽  
Reactor Model

Flameless combustion (FC) is one of the most promising techniques of reducing harmful emissions from combustion systems. FC is a combustion phenomenon that takes place at low O2 concentration and high inlet reactant temperature. This unique combination results in a distributed combustion regime with a lower adiabatic flame temperature. The paper focuses on investigating the chemical kinetics of an prototype combustion chamber built at the university of Cincinnati with an aim of establishing flameless regime and demonstrating the applicability of FC to gas turbine engines. A Chemical reactor model (CRM) has been built for emulating the reactions within the combustor. The entire combustion chamber has been divided into appropriate number of Perfectly Stirred Reactors (PSRs) and Plug Flow Reactors (PFRs). The interconnections between these reactors and the residence times of these reactors are based on the PIV studies of the combustor flow field. The CRM model has then been used to predict the combustor emission profile for various equivalence ratios. The results obtained from CRM model show that the emission from the combustor are quite less at low equivalence ratios and have been found to be in reasonable agreement with experimental observations. The chemical kinetic analysis gives an insight on the role of vitiated combustion gases in suppressing the formation of pollutants within the combustion process.

scholarly journals A coupled flow and chemical reactor network model for predicting gas turbine combustor performance

2020 ◽  
Vol 24 (3 Part B) ◽  
pp. 1977-1989
Author(s):  
Seyfettin Hataysal ◽  
Ahmet Yozgatligil
Keyword(s):  
Gas Turbine ◽  
Network Model ◽  
Chemical Reactor ◽  
Gas Turbine Combustor ◽  
Actual Performance ◽  
Flow Network ◽  
Average Temperature ◽  
Chemical Reactor Network ◽  
Segregated Flow ◽  
Reactor Network

Gas turbine combustor performance was explored by utilizing a 1-D flow network model. To obtain the preliminary performance of combustion chamber, three different flow network solvers were coupled with a chemical reactor network scheme. These flow solvers were developed via simplified, segregated and direct solutions of the nodal equations. Flow models were utilized to predict the flow field, pressure, density and temperature distribution inside the chamber network. The network model followed a segregated flow and chemical network scheme, and could supply information about the pressure drop, nodal pressure, average temperature, species distribution, and flow split. For the verification of the model?s results, analyses were performed using CFD on a seven-stage annular test combustor from TUSAS Engine Industries, and the results were then compared with actual performance tests of the combustor. The results showed that the preliminary performance predictor code accurately estimated the flow distribution. Pressure distribution was also consistent with the CFD results, but with varying levels of conformity. The same was true for the average temperature predictions of the inner combustor at the dilution and exit zones. However, the reactor network predicted higher elemental temperatures at the entry zones.

Novel Unsteady Temperature/Heat Transfer Instrumentation and Measurements in the Presence of Combustor Instabilities

2005 ◽  
Author(s):  
K. S. Chana ◽  
K. J. Syed ◽  
M. I. Wedlock ◽  
R. W. Copplestone ◽  
M. S. Cook ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Gas Turbine ◽  
Temperature Fluctuations ◽  
Operating Conditions ◽  
Main Reaction ◽  
Wall Heat Transfer ◽  
Unsteady Temperature ◽  
Pressure Dynamics ◽  
The Impact

Lower NOx emissions from gas turbine combustion systems can be achieved through reducing the equivalence ratio of the main reaction zone and/or increasing the burner pressure drop. This strategy however takes pressure drop and/or air away from the combustor cooling, thereby compromising the combustor life. In order to achieve an optimum design that is a good compromise between low emissions and long component life, accurate heat transfer prediction is essential. It is well known that free stream turbulence can influence wall heat transfer characteristics. However the impact of combustion induced pressure dynamics, and the associated unsteady fluid dynamics, upon combustor wall heat transfer has not been adequately investigated. This paper reports on combustion tests conducted at gas turbine operating conditions, where pressure dynamics have been controlled by altering combustor operating conditions and through the use of a siren placed in the upstream air flow. Combustor wall temperatures were measured using standard thermocouples and QinetiQ’s “True Surface Thermocouples” (TST). The latter, which were mounted on the hot gas surface of the wall, are capable of a fast response and are capable of indicating the temperature fluctuations experienced by the metal surface. Fourier analysis of the TSTs showed no particular peaks associated with the pressure dynamics. This suggests that any coherence is damped within the boundary layer or by the thermal inertia of the metal. However temperature fluctuations of up to about 100°C were detected.

scholarly journals Analysis of in-cylinder pressure oscillation and its effect on wall heat transfer

2020 ◽  
pp. 146808742093236
Author(s):  
Mateos Kassa ◽  
Thomas Leroy ◽  
Anthony Robert ◽  
Fabien Vidal-Naquet
Keyword(s):  
Heat Transfer ◽  
Combustion Chamber ◽  
Acoustic Waves ◽  
Pressure Oscillation ◽  
Operating Conditions ◽  
Acoustic Properties ◽  
Wall Heat Transfer ◽  
Cylinder Pressure ◽  
Pressure Oscillations ◽  
Trapped Gas

In-cylinder pressure oscillations in internal combustion engines have been associated with increased heat losses and damages to the engine components. The links between the acoustic waves and the increased heat transfer (and potentially ensuing engine damages) have not yet been well understood. In this study, a high-fidelity large eddy simulation model incorporating an auto-ignition model is used to simulate the combustion process and the associated pressure oscillation at various engine operating conditions. The study serves to develop a better understanding of the acoustic waves in a combustion chamber and their effect on wall heat transfer. First, a simplified model of the pressure oscillations is proposed and shown to accurately characterize the pressure in the combustion chamber. Second, the simplified pressure model and acoustic theory are leveraged to develop a model of the in-cylinder gas velocities. Finally, a heat transfer model is presented that takes into consideration the pressure/velocity oscillations and the inherent acoustic properties of the trapped gas. The increase in heat transfer is shown to primarily stem from an increased heat transfer coefficient due to the velocity oscillations of the trapped gas. The results are consistent with previously observed experimental measurements of the heat flux in the presence of pressure oscillations.

Heat Transfer and Flow Studies of Different Cooling Configurations for Gas Turbine Rotor Blade

2014 ◽  
Author(s):  
Batchu Suresh ◽  
Ainapur Brijesh ◽  
V. Kesavan ◽  
S. Kishore Kumar
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Film Cooling ◽  
Metal Temperature ◽  
Coolant Temperature ◽  
Fe Model ◽  
Transfer Coefficients ◽  
Flow Network ◽  
Blade Cooling ◽  
Film Cooling Holes

Military gas turbine engine operates at turbine entry temperatures (TET) of the order of 2000K. Increase in TET improves thermal efficiency and power output. The gas temperature is far above the allowable metal temperature of turbine components. Hence, there is a need to cool the components such as blades and vanes for safe operation. The blades are cooled by combination of internal convective cooling and external film-cooling. Rib tabulators are widely used in blade cooling passages to enhance heat transfer. In the present study, different rib tabulator configurations have been studied. 1D flow network model of blade cooling passages have been modeled using Flowmaster software. Flowmaster software estimates pressure losses, rotational effects and heat transfer of the coolant flow in the blade passages. Cooling passages are modeled as ducts while film cooling holes, impingement holes, tip holes and ejection holes are modeled as orifices. Experimentally measured heat transfer and pressure loss correlations are used in the analysis. The coolant pressure at inlet and sink pressure at exit of film cooling holes are given as input. The heat load coming on to the blade is also given as input for predicting the coolant temperature rise and blade metal temperature. The thermal analysis is carried out with different shaped rib turbulators such as V and W ribs with broken and continuous pattern. It is observed that thermal performance factor for a broken V rib configuration is better than other configurations. The metal temperature for broken V ribbed configuration is 25°C less compared other configurations. The effect of rotation on the blade temperature is also studied. The convective bulk temperatures and convective heat transfer coefficients obtained from 1D flow network are applied on 2D Finite Element (FE) model to obtain nodal temperature distribution.

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