scholarly journals Experimental and Numerical Investigation of a MILD Combustion Chamber for Micro Gas Turbine Applications

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3363 ◽  
Author(s):  
Valentina Fortunato ◽  
Andres Giraldo ◽  
Mehdi Rouabah ◽  
Rabia Nacereddine ◽  
Michel Delanaye ◽  
...  
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Energy Production ◽  
Kinetic Mechanism ◽  
Combustion Model ◽  
Low Oxygen ◽  
Micro Gas Turbine ◽  
Air Inlet ◽  
Mild Combustion ◽  
Stirred Reactor

In the field of energy production, cogeneration systems based on micro gas turbine cyclesappear particularly suitable to reach the goals of improving efficiency and reducing pollutants.Moderate and Intense Low-Oxygen Dilution (MILD) combustion represents a promising technologyto increase efficiency and to further reduce the emissions of those systems. The present work aims atdescribing the behavior of a combustion chamber for a micro gas turbine operating in MILD regime.The performances of the combustion chamber are discussed for two cases: methane and biogascombustion. The combustor performed very well in terms of emissions, especially CO and NOx,for various air inlet temperatures and air-to-fuel ratios, proving the benefits of MILD combustion.The chamber proved to be fuel flexible, since both ignition and stable combustion could be achievedby also burning biogas. Finally, the numerical model used to design the combustor was validatedagainst the experimental data collected. The model performs quite well both for methane and biogas.In particular, for methane the Partially Stirred Reactor (PaSR) combustion model proved to be thebest choice to predict both minor species, such as CO, more accurately and cases with lower reactivitythat were not possible to model using the Eddy Dissipation Concept (EDC). For the biogas, the mostappropriate kinetic mechanism to properly model the behavior of the chamber was selected

Actuation Studies for Active Control of Mild Combustion for Gas Turbine Application

2014 ◽  
Author(s):  
Emilien Varea ◽  
Stephan Kruse ◽  
Heinz Pitsch ◽  
Thivaharan Albin ◽  
Dirk Abel
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Active Control ◽  
Gas Turbines ◽  
Reverse Flow ◽  
Air Flow ◽  
Combustion Regime ◽  
Nox Emissions ◽  
Low Oxygen ◽  
Mild Combustion

MILD combustion (Moderate or Intense Low Oxygen Dilution) is a well known technique that can substantially reduce high temperature regions in burners and thereby reduce thermal NOx emissions. This technology has been successfully applied to conventional furnace systems and seems to be an auspicious concept for reducing NOx and CO emissions in stationary gas turbines. To achieve a flameless combustion regime, fast mixing of recirculated burnt gases with fresh air and fuel in the combustion chamber is needed. In the present study, the combustor concept is based on the reverse flow configuration with two concentrically arranged nozzles for fuel and air injections. The present work deals with the active control of MILD combustion for gas turbine applications. For this purpose, a new concept of air flow rate pulsation is introduced. The pulsating unit offers the possibility to vary the inlet pressure conditions with a high degree of freedom: amplitude, frequency and waveform. The influence of air flow pulsation on MILD combustion is analyzed in terms of NOx and CO emissions. Results under atmospheric pressure show a drastic decrease of NOx emissions, up to 55%, when the pulsating unit is active. CO emissions are maintained at a very low level so that flame extinction is not observed. To get more insights into the effects of pulsation on combustion characteristics, velocity fields in cold flow conditions are investigated. Results show a large radial transfer of flow when pulsation is activated, hence enhancing the mixing process. The flame behavior is analyzed by using OH* chemiluminescence. Images show a larger distributed reaction region over the combustion chamber for pulsation conditions, confirming the hypothesis of a better mixing between fresh and burnt gases.

A Micro Gas Turbine Fuelled by Methane-Hydrogen Blends

2012 ◽  
Vol 232 ◽  
pp. 792-796 ◽  
Author(s):  
Fabrizio Reale ◽  
Raffaela Calabria ◽  
Fabio Chiariello ◽  
Rocco Pagliara ◽  
Patrizio Massoli
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Hydrogen Oxidation ◽  
Kinetic Mechanism ◽  
Chemical Kinetic ◽  
Combustion Efficiency ◽  
Point Of View ◽  
Combustion Model ◽  
Numerical Computations ◽  
Micro Gas Turbine

The combustion efficiency and the gaseous emission of a 100 kWe MGT, designed for working with natural gas but fuelled with blends containing up to 10% of hydrogen is investigated. A critical comparison between experimental data and results of the CFD analysis of the combustor is discussed. The k-epsilon RANS turbulence model and the Finite Rate – Eddy Dissipation combustion model were used in the numerical computations. The chemical kinetic mechanisms embedded were the 2-step Westbrook and Dryer for methane oxidation, 1-step Westbrook and Dryer for hydrogen oxidation and the Zeldovich mechanism for NO formation. The experimental data and numerical computations are in agreement within the experimental accuracy for NO emissions. Regarding CO, there is a significant deviation between experimental and computational data due to the scarce predictive capability of the simple two steps kinetic mechanism was adopted. From a practical point of view, the possibility of using fuels with a similar Wobbe index was confirmed. In particular the addiction of 10 % of hydrogen to pure methane doesn’t affect the behavior of the micro gas turbine either in terms of NO or CO emissions.

scholarly journals Conceptual Approach to Combustor Nozzle and Reformer Characteristics for Micro-Gas Turbine with an On-Board Reforming System: A Novel Thermal and Low Emission Cycle

2020 ◽  
Vol 12 (24) ◽  
pp. 10558
Author(s):  
Jonghyun Kim ◽  
Jungsoo Park
Keyword(s):  
Gas Turbine ◽  
Thermal Power ◽  
Open Loop ◽  
Inlet Temperature ◽  
Outlet Temperature ◽  
Low Oxygen ◽  
Conceptual Approach ◽  
Micro Gas Turbine ◽  
Mild Combustion ◽  
Heavy Duty Gas Turbine

In order to implement moderate or intensive low oxygen dilution (MILD) combustion, it is necessary to extend the flame stability and operating range. In the present study, the conceptual designs of a combustor single nozzle and reformer were numerically suggested for a micro-gas turbine with an on-board reformer. The target micro-gas turbine achieved a thermal power of 150 kW and a turbine inlet temperature (TIT) of 1200 K. Studies on a nozzle and reformer applying an open-loop concept have been separately conducted. For the nozzle concept, a single down-scaled nozzle was applied based on a reference nozzle for a heavy-duty gas turbine. The nozzle can achieve a good mixture with a high swirl with a splined swirl curve lower NOx emissions and smaller pressure drop in the combustor. The concept of the non-catalytic partial-oxidation reforming reformate was designed using the combustor outlet temperature (COT) of the exhaust gas. Feasible hydrogen yields were mapped through the reformer. Based on the hydrogen yields from the reformer, hydrogen was added to the nozzle to investigate its combustion behavior. By increasing the hydrogen addition and decreasing the O2 fraction, the OH concentrations were decreased and widely distributed similar to the fundamental characteristics of MILD combustion.

Monte Carlo Simulation for Radiative Transfer in a High-Pressure Industrial Gas Turbine Combustion Chamber

2017 ◽  
Author(s):  
Tao Ren ◽  
Michael F. Modest ◽  
Somesh Roy
Keyword(s):  
Monte Carlo ◽  
Gas Turbine ◽  
Radiation Effects ◽  
Swirling Flow ◽  
Calculation Model ◽  
Navier Stokes ◽  
Combustion Model ◽  
Stirred Reactor ◽  
Industrial Gas Turbine ◽  
Gas Turbine Burner

Radiative heat transfer is studied numerically for reacting swirling flow in an industrial gas turbine burner operating at a pressure of 15 bar. The reacting field characteristics are computed by Reynolds-averaged Navier-Stokes (RANS) equations using the k-ε model with the partially stirred reactor (PaSR) combustion model. The GRI-Mech 2.11 mechanism, which includes nitrogen chemistry, is used to demonstrate the the ability of reducing NOx emissions of the combustion system. A Photon Monte Carlo (PMC) method coupled with a line-by-line spectral model is employed to accurately account for the radiation effects. CO2, H2O and CO are assumed to be the only radiatively participating species and wall radiation is considered as well. Optically thin and PMC-gray models are also employed to show the differences between the simplest radiative calculation models and the most accurate radiative calculation model, i.e., PMC-LBL, for the gas turbine burner. It was found that radiation does not significantly alter the temperature level as well as CO2 and H2O concentrations. However, it has significant impacts on the NOx levels at downstream locations.

Development of Advanced Combustor for Biomass

2011 ◽  
Author(s):  
Masato Urashima ◽  
Shuichi Torii
Keyword(s):  
Energy Source ◽  
Renewable Energy Source ◽  
Renewable Energy ◽  
Municipal Solid Waste ◽  
Combustion Chamber ◽  
Solid Waste ◽  
Gas Turbine ◽  
The Sun ◽  
Waste Oil ◽  
Micro Gas Turbine

Biomass is a renewable energy source in that the energy that it contains comes from the sun. One of sources of biomass is municipal solid waste. The final goal of the study is to develop the combustor for the micro gas-turbine using the biomass as a fuel. Here, it is very important to remove ashes (10μm or more in diameter) in the gas because its size affects the strength or erosion of the turbine blade. The aim of the present study is to observe the combustion phenomena relevant to a mixture of waste liquid and waste oil. Emphasis is placed on the ash size which is produced from the combustion chamber developed here. It is found that the ash size obtained at the exit of the combustor is less than 10 μm.

OH* Chemiluminescence and OH-PLIF Measurements in a Micro Gas Turbine Combustor

2010 ◽  
Author(s):  
Martina Hohloch ◽  
Rajesh Sadanandan ◽  
Axel Widenhorn ◽  
Wolfgang Meier ◽  
Manfred Aigner
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Thermal Power ◽  
Gas Turbine Combustor ◽  
Maximum Heat ◽  
Micro Gas Turbine ◽  
Power Load ◽  
Reaction Zones ◽  
Maximum Heat Release

In this work the combustion behavior of the Turbec T100 natural gas/air combustor was analyzed experimentally. For the visualization of the flame structures at various stationary load points OH* chemiluminescence and OH-PLIF measurements were performed in a micro gas turbine test rig equipped with an optically accessible combustion chamber. The OH* chemiluminescence measurements are used to get an impression of the shape and the location of the heat release zones. In addition the OH-PLIF measurements enabled spatially and temporarily resolved information of the reaction zones. Depending on the load point the shape of the flame was seen to vary from cylindrical to conical. With increasing thermal power load the maximum heat release zones shift to a lifted flame. Moreover, the effect of the optically accessible combustion chamber on the performance of the micro gas turbine is evaluated.

scholarly journals Design and Experimental Validation of a Supersonic Concentric Micro Gas Turbine

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Gabriel Vézina ◽  
Hugo Fortier-Topping ◽  
François Bolduc-Teasdale ◽  
David Rancourt ◽  
Mathieu Picard ◽  
...  
Keyword(s):  
Steady State ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Structural Model ◽  
Structural Integrity ◽  
Turbine Blades ◽  
External Diameter ◽  
Impulse Turbine ◽  
Micro Gas Turbine ◽  
Steady State Operation

This paper presents the design and experimental results of a new micro gas turbine architecture exploiting counterflow within a single supersonic rotor. This new architecture, called the supersonic rim-rotor gas turbine (SRGT), uses a single rotating assembly incorporating a central hub, a supersonic turbine rotor, a supersonic compressor rotor, and a rim-rotor. This SRGT architecture can potentially increase engine power density while significantly reducing manufacturing costs. The paper presents the preliminary design of a 5 kW SRGT prototype having an external diameter of 72.5 mm and rotational speed of 125,000 rpm. The proposed aerodynamic design comprises a single stage supersonic axial compressor, with a normal shock in the stator, and a supersonic impulse turbine. A pressure ratio of 2.75 with a mass flow rate of 130 g/s is predicted using a 1D aerodynamic model in steady state. The proposed combustion chamber uses an annular reverse-flow configuration, using hydrogen as fuel. The analytical design of the combustion chamber is based on a 0D model with three zones (primary, secondary, and dilution), and computational fluid dynamics (CFD) simulations are used to validate the analytical model. The proposed structural design incorporates a unidirectional carbon-fiber-reinforced polymer rim-rotor, and titanium alloy is used for the other rotating components. An analytical structural model and numerical validation predict structural integrity of the engine at steady-state operation up to 1000 K for the turbine blades. Experimentation has resulted in the overall engine performance evaluation. Experimentation also demonstrated a stable hydrogen flame in the combustion chamber and structural integrity of the engine for at least 30 s of steady-state operation at 1000 K.

scholarly journals A swirler stabilized combustion chamber for a micro-gas turbine fuelled with natural gas

2012 ◽  
Vol 34 (4) ◽  
pp. 441-449 ◽  
Author(s):  
Guenther C. Krieger ◽  
André P. V. de Campos ◽  
Fernando L. Sacomano Filho ◽  
Rafael C. de Souza
Keyword(s):  
Natural Gas ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Micro Gas Turbine

High Performance and Cost Effective Recuperator for Micro-Gas Turbines

2002 ◽  
Author(s):  
Gunnar Lagerstro¨m ◽  
Max Xie
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
Electrical Power ◽  
Cost Effective ◽  
Piping System ◽  
Micro Gas Turbine ◽  
Air Inlet ◽  
Manufacturing Technologies ◽  
Air Cells

Rekuperator Svenska AB owned by VOLVO Technology Transfer Corporation and Avesta Polarit, has successfully developed a completely laser welded recuperator for micro-gas turbine applications. Tests have shown that the thermal performance is very competitive. The recuperator was installed in a 100 kW(e) micro-gas turbine power plant for combined electricity and heat generation by a customer. The recuperator is a primary surface counter flow heat exchanger with cross corrugated duct configuration. The primary heat transfer surface plate patterns are stamped and a pair of the plates are laser welded to form an air cell. The air cells are then stacked and laser welded together to form the recuperator core which is tied between two end beams. Manifolds for air inlet and outlet as well as piping system are welded to the core. Through varying the number of air cells the recuperator core can easily be adapted for micro-gas turbine applications with different output rates of electrical power. The key manufacturing technologies are stamping of the air cell plates and laser welding of the air cells. These processes can be fully automated for mass production at low costs.

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