Combustor Of Micro Gas Turbine Research Articles

Cooling characteristics of dilution holes in can-type combustor of micro gas turbine

For the purpose of studying the effect of structural changes in the dilution zone on the main performance evaluation parameters of the combustor, a can-type combustor of a micro gas turbine containing 16 dilution holes was used as the original structure. Seven optimization cases were designed by adjusting the number of dilution holes and the area of single hole in the range of hole numbers from 8 to 28 while keeping the total area of dilution holes. The main conclusions obtained by the numerical simulation study are as follows. The total flow of the dilution zone decreases with the number of holes reduce but due to the increase of single hole flow with the area, the airflow rigidity is significantly enhanced, so the entire airflow is disturbed more strongly and the dilution effect is strengthened. In general, the total pressure loss of the combustor presented an increasing trend with the decrease in the number of holes, and the pressure loss reaches a minimum value of 3400 Pa when the number of holes is 14. The combustion efficiency decreased as the number of holes increased, when the hole numbers increased to 20, the combustion efficiency dropped abruptly below 95%. The variation tendency of outlet temperature distribution factor (OTDF) is generally consistent with the combustion efficiency, and the minimum OTDF is 0.29 for the number of holes of 28. In summary, compared with the original structure with 16 holes, the OTDF decreases by 7.69%, the NOx concentration decreases by 16.67%, and the combustion efficiency increases by 3.1% when the number of holes is 8. Although the total pressure loss is increased by 8%, it is still within a reasonable range. Therefore the combustor with 8 holes can be considered a better optimized case.

Aerothermal Performance and Soot Emissions of Reacting Flow in a Micro-Gas Turbine Combustor

Micro-gas turbines are used for power generation and propulsion in unmanned aerial vehicles. Despite the growing demand for electric engines in a world striving for a net zero carbon footprint, combustion gas turbines will continue to play a critical role. Hence, there is a need for improved micro-gas turbines that can meet stringent environmental regulations. This paper is the first part of a comprehensive study focused on understanding the fundamental performance and emission characteristics of a micro-gas turbine model, with the aim of finding ways to enhance its operation. The study used a multidisciplinary CFD model to simulate the reacting flow in the combustion chamber and validated the results against experimental data and throughflow simulations. The present work is one of the few work that attempts to address both the aerothermal performance and emissions of the gas turbine. The findings highlight that parameters such as non-uniform outlet pressure, fuel-to-air ratio, and fuel injection velocity can greatly influence the performance and emissions of the micro-gas turbine. These parameters can affect the combustion efficiency, the formation of hot spots at the combustor–turbine interface, and the soot emissions. The results provide valuable insights for optimizing the performance and reducing the emissions of micro-gas turbines and serve as a foundation for further research into the interaction between the combustor and the turbine.

Numerical and Experimental Study on Combustion Characteristics of Micro-Gas Turbine Biogas Combustor

The use of biogas in land-based gas turbines for power generation is a promising approach to reducing greenhouse gases and our dependence on fossil fuels. The focus of this research was to investigate the fuel/air mixing and combustion performance in an DLE (dry low emission) type can combustor designed for a micro-gas turbine. The fuel and air mixing uniformity was studied considering the air flow characteristic and fuel injection performance through the numerical simulation. The influence of the fuel/air mixing characteristics on the combustion characteristics was studied by numerical simulation and experimental tests. The combustion characteristics studied included the temperature field in the combustor, the pattern factor at the combustor outlet, combustion efficiency, and pollutant emission characteristics. The results show the position of the fuel nozzle has little effect on the mixing uniformity due to the limited mixing space for the micro-gas turbine combustor, while there are optimal fuel nozzle diameters to generate the suitable fuel jet momentum for the mixing process. The fuel/air mixing characteristics had an obvious influence on the combustion performance for the studied DLE combustor. The increase in the fuel air mixing uniformity can decrease the NOx emissions and generate a better temperature distribution at the combustor outlet. The increased mixing uniformity may decrease the combustion efficiency and increase the CO emissions of the micro-gas turbine combustor.

Numerical prediction of operating characteristics of micro-gas turbine combustor with on-board reformed EGR system using co-simulation model and 1D reduced model

In this study, an on-board reforming gas turbine system was proposed to expend the combustion stability and operating points of as gas turbine combustor aiming for fuel lean condition. On-board reforming does not store the syngas unlike the existing conventional reforming device, but formed syngas as the operating load changes and participates in combustion. In previous research conducted for this study, a concept single nozzle combustor was designed that satisfies the thermal output of 150 kW and the turbine inlet temperature of 1200 K. In addition, by designing a non-catalytic partial oxidation-based concept reformer, syngas formation was confirmed in various operation points. In previous research, closed-loop analysis was performed to analyze the independent effects of combustor and reformer. However, in this study, open-loop analysis that simulates the combustor and reformer simultaneously was performed to analyze the effect of the combined system at various operating points. As a result, improved combustion was confirmed by the generation of OH radicals when the oxidizing agent was diluted with increasing hydrogen content. This is similar to the lean OH radical distribution in a low-oxidizing environment, which is the basic characteristics of moderate or intense low-oxygen dilution combustion. The reformer analyzed the reaction by changing the reformate fuel inlet velocity. Through this, it was confirmed that the mixedness inside the reformer improved as the reformate fuel inlet velocity. Finally, to calculate the efficiency of the hydrogen addition operating points under various conditions, suitable operating points were derived by comparison with conventional partial oxidation reforming. The operating range of moderate or intense low oxygen dilution combustion in an on-board reforming gas turbine system was numerically predicted. This is expected to greatly contribute to the study to improve the stability of moderate or intensive low oxygen dilution combustion in the future.

Study on the Fuel Flexibility of a Microgas Turbine Combustor Burning Different Mixtures of H2, CH4, and CO2

Abstract The aim of this work is to analyze the behavior of the fuel flexible Ansaldo ARI100 T2 microgas turbine (MGT) combustor operated with mixtures having different H2, CH4, and CO2 concentrations. This combustor is going to be installed on an in-house modified Turbec T100 P MGT, which is originally equipped with a methane fired combustor. In a previous study, the combustor was simulated with a H2 enriched syngas, whose Wobbe index was within the limits imposed by the syngas supply system of an Ansaldo test bench. In this study, this constraint has been removed to gain a deeper understanding on how the fuel mixture properties (composition, heating value, and laminar flame speed) affect combustor performance. To this end, a series of Reynolds-averaged Navier–Stokes (RANS) computational fluid dynamics (CFD) simulations have been carried out on the full-scale 3D geometry of the combustion chamber, at full and partial load (50%), evaluating for each case combustion efficiency as well as NOx and CO emissions.

Effect of carbon dioxide content in biogas on turbulent combustion in the combustor of micro gas turbine

China has huge potential on biogas resources and the distributed energy system (DES) based on micro gas turbine provides an effective way for biogas utilization. In this work, turbulent combustion characteristics in the combustor of micro gas turbine for DES were numerically and experimentally studied, and the effect of carbon dioxide content in biogas on the turbulent flame was mainly analyzed. Turbulent flames structures of natural gas and three kinds of biogas under various equivalence ratios were measured by three-dimensional (3D) combustion diagnostic technique based on computed tomography of chemiluminescence (CTC). The results show that the carbon dioxide content in the fuel has a great influence on flame structure of turbulent combustion. The increase of carbon dioxide content in the fuel not only reduces turbulent combustion rate, but also makes the combustion stability worse. With the decrease of equivalence ratio, the effect becomes greater. With the increase of carbon dioxide volume fraction, combustion flame is gradually away from the outlet of the nozzle. When volume fraction of carbon dioxide is 50%, the distance between the combustion flame and the nozzle outlet increases the 100 mm. Furthermore, carbon dioxide weakens the effect of excess air on the CH* distribution and turbulent flame.

Design and Numerical Simulation of a Micro-Gas Turbine Combustor

Design and Numerical Simulation of a Micro-Gas Turbine Combustor

Dependence of unburnt ammonia on combustor inlet temperature of ammonia combustor of micro gas turbine

Dependence of unburnt ammonia on combustor inlet temperature of ammonia combustor of micro gas turbine

CFD Study of a MGT Combustor Supplied with Syngas

Abstract The authors discuss in this paper the potential of a micro gas turbine (MGT) combustor when operated under unconventional conditions, in terms of variation in the fuel supplied. The authors’ expertise in the field of micro-combustor has addressed, in recent years, some topics of current interest, as the fuelling with gaseous and liquid biofuels and the NOx reduction through the optimization of the combustor. While the previous authors’ works were mainly referring to a tubular combustor of a 100kW MGT, the present proposal deals with an annular, reverse flow combustor of a 30kW MGT. In this case the particular location of both the injectors and of the secondary and diluting holes allows the combustor process to develop under nearly RQL conditions. This is of special interest when supplying the combustion chamber with low LHV fuels. In addition, recent authors’ papers have demonstrated that the integration of the MGT with a solar field leads the combustor to require a decreased fuel/air equivalence ratio because of the higher air entry temperature. Under these aspects, the existence of a Rich region within the combustor may be helpful for the early phases of the oxidation process. The pollutant formation rates should be effectively controlled by the secondary (Quick-mix) and diluting (Lean) air flows. The authors’ methodology relies on an advanced CFD approach that makes use of a reaction scheme coupled with an accurate study of the turbulent interaction of the reacting species. Extended kinetic mechanisms are also included in the combustion model. A preliminary set-up of the model will be based on the combustion analysis with boundary conditions provided by thermodynamic analysis of the micro-turbine. Several computational examples are discussed, namely: - The analysis of the combustor response with reduced equivalence ratios or changes in the inlet air conditions; - The comparison of combustion efficiency and pollutant production with different fuels.

E111 マイクロマシン・ガスタービン用液焚き燃焼器の基礎的研究(OS1 マイクロエネルギー変換)

Micro gas turbine systems have been developed as a portable power supply. In this study the utilization of kerosene spray with pre-vaporized system for the micro gas turbine combustor was tested. Characteristics of the model combustor of micro gas turbine were investigated experimentally. Twin fluid atomizer was used for the fuel spray formation. An extension tube was set at the exit of fuel injector for the enhancement of pre-vaporization. The effect of the extension tube on flame stability was discussed. As a result, the blow off limit became wider when the extension tube was set at fuel nozzle exit.

Computational study of a micro-turbine engine combustor using Large Eddy Simulation and Reynolds Averaged turbulence models

A computational study of the combustion process inside micro-turbine engines is presented. Different turbulence models are assessed and results are compared against experimental data. Results indicate that RANS models and LES with dynamic Smagorinsky sub-grid model fail to achieve convergence or accurate solutions at the meshes employed in this study. Less accurate results are obtained for the DES when compared with LES-WALE. In terms of the combustion, the outlet flow presents temperature gradients that are likely to affect the turbine performance. References M. D. Agrawal and S. Bharani. Performance Evaluation of a Reverse-flow Gas Turbine Combustor using Modified Hydraulic Analogy. The institute of Engineers India Journal MC, April 2004:34--44, 2004. http://www.ieindia.org/publish/mc/0404/apr04mc7.pdf HeonSeok Lee and JeongJung Yoon. The Study on Development of Low NOx Combustor with Lean Burn Characteristics for 20kW class Microturbine. 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Combustion Characteristics in a Micro-Gas Turbine Combustor with a Recirculation Zone Induced by an Upward Swirl

Combustion Characteristics in a Micro-Gas Turbine Combustor with a Recirculation Zone Induced by an Upward Swirl

加圧型MCFC/MGTハイブリッドシステムの開発(マイクロ・小型分散・発電プラントにおける燃料電池最新技術,マイクロ・小型分散・発電プラントにおける燃料電池最新技術)

A pressurized Molten Carbonate Fuel Cell (MCFC) / Micro Gas Turbine (MGT) hybrid system has been developing to demonstrate high efficiency and very low NOx and SOx emission. The 300kWe MCFC / MGT hybrid Co-generation system is in test at the TOYOTA Environmental Center. An inferred system efficiency has been nearly achieved, and this system has been possible to operate with no firing of MGT combustor in the range of 75% to 100% load. The developed MGT and control method of this system are focused in this paper.