Volume 3A: Combustion, Fuels, and Emissions最新文献

{"title":"Scale Resolving CFD Investigations of Aerothermal Field and Emissions of a Lean Burn Aeroengine Combustor","authors":"Simone Paccati, L. Mazzei, A. Andreini, S. Patil, S. Shrivastava, D. Bessette, C. Arguinzoni, Rakesh Yadav","doi":"10.1115/gt2021-59387","DOIUrl":"https://doi.org/10.1115/gt2021-59387","url":null,"abstract":"\u0000 Due to the increasingly stringent international limitations in terms of NOx emissions, the development of new combustor concepts has become extremely important in order for aircraft engines to comply with these regulations. In this framework, lean-burn technology represents a promising solution and several studies and emission data from production engines have proven that it is more promising in reducing NOx emissions than rich-burn technology.\u0000 Considering the drawbacks of this combustion strategy (flame stabilization, flashback or blowout or the occurrence of large pressure fluctuations causing thermo-acoustics phenomena) as well as the difficulties and the high costs related to experimental campaigns at relevant operating conditions, Computational Fluid Dynamics (CFD) plays a key role in deepening understanding of the complex phenomena that are involved in such reactive conditions.\u0000 During last years, large research efforts have been devoted to develop new advanced numerical strategies for high-fidelity predictions in simulating reactive flows that feature strong unsteadiness and high levels of turbulence intensity with affordable computational resources. In this sense, hybrid RANS-LES models represent a good compromise between accurate prediction of flame behaviour and computational cost with respect to fully-LES approaches. Stress-Blended Eddy Simulation (SBES) is a new global hybrid RANS-LES methodology which ensures an improved shielding of RANS boundary layers and a more rapid RANS-LES “transition” compared to other hybrid RANS-LES formulations.\u0000 In the present work, a full annular aeronautical lean-burn combustor operated at real conditions is investigated from a numerical point of view employing the new SBES approach using poly-hexcore mesh topology, which allows to adopt an isotropic grid for more accurate scale-resolving calculations by means of fully regular hexahedral elements in the main stream. The results are compared to experimental data and to previous reference numerical results obtained with Scale Adaptive Simulation formulation on a tetrahedral mesh grid in order to underline the improvements achieved with the new advanced numerical setup.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125589226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Atmospheric Testing of a High Hydrogen FlameSheet™ Combustor for the OP16 Gas Turbine","authors":"Thijs Bouten, J.A.M. Withag, L. Axelsson, Joris Koomen, D. Jansen, P. Stuttaford","doi":"10.1115/gt2021-59236","DOIUrl":"https://doi.org/10.1115/gt2021-59236","url":null,"abstract":"\u0000 Gas turbines with a combustion system for hydrogen operation offer a low carbon solution to support the stability of the energy grid. This provides a solution capturing the needs for energy storage, in the form of hydrogen, and flexible power generation. Fuel flexibility is a key requirement to reduce the operational risks in case hydrogen is not available, whereby hydrogen can be combined with other conventional or alternative fuels. A key issue to achieve 100% hydrogen combustion with low emissions is to prevent flashback. To address the challenges, a project consortium was set-up consisting of gas turbine equipment manufacturers, academia and end-users. The major objective is to develop a cost-effective, ultra-low emissions (sub 9 ppm NOx and CO) combustion system for gas turbines in the 1–300 MW output range, including the 1.85 MWe OPRA OP16 gas turbine.\u0000 At the center of this innovative high-technology project is the patented and novel aerodynamic trapped vortex FlameSheet™ combustion technology platform. Burner concepts based on an aerodynamically trapped vortex flame stabilization have a higher resistance towards flame blowout than conventional swirl stabilized burners. This paper will present the results of the first phase of the project, whereby atmospheric testing of the upgraded FlameSheet™ combustor has been performed operating on natural gas, hydrogen and mixtures thereof. The optimized combustor configurations demonstrated a wide load range on 100% hydrogen, and these results will be presented.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130162852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Validation of a Novel Test-Rig for RQL Flame Dynamics Studies","authors":"Martin March, Julian Renner, C. Hirsch, T. Sattelmayer","doi":"10.1115/gt2021-58602","DOIUrl":"https://doi.org/10.1115/gt2021-58602","url":null,"abstract":"\u0000 In this paper a novel test-rig for the investigation of low-frequency thermoacoustic instabilities in aero-engines with air-staging RQL (rich-quench-lean) is presented. The new approach is to separate the rich primary zone from the lean secondary zone to allow for an isolated thermoacoustic characterization of each combustion zone. In addition the test-rig offers the possibility to combine both zones to judge the transferability of the findings from the separated to the compact configuration. The high modularity of the test-rig is already considered in the design-phase and allows a cost and time efficient manufacturing. Heat losses in the primary zone and the transition duct between the two zones play a crucial role for the functionality of the facility and are estimated during design to guarantee a stable re-ignition in the secondary zone. The main design steps in the secondary zone for achieving complete burn-out of the hot primary combustion gases are described. The realization of the acoustic excitation via loudspeakers is described and damping measures to improve combustor stability are explained. The operation of both zones, their acoustic behavior and the operational limits of the test-rig are demonstrated experimentally. They include first thermoacoustic measurement data of naturally occurring instabilities, the corresponding eigenfrequencies and the validation of the test-rig design. Finally an outlook on the future work in the research project concludes this paper.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"38 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120889507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Study of Thermal Performance and NOx Emission for An Ammonia-Fuelled Micro-Combustor With Ring-Shaped Ribs in Lean Combustion","authors":"Siliang Ni, Dan Zhao","doi":"10.1115/gt2021-59226","DOIUrl":"https://doi.org/10.1115/gt2021-59226","url":null,"abstract":"\u0000 As a renewable energy source, ammonia is regarded as one of the ideal gases that can replace fossil fuels and has been extensively studied in large-scale combustion. However, studies on energy conversion efficiency and NOx emission in microscale are still inadequate. In this work, ammonia/oxygen premixed cylindrical micro-combustors with inner ribs under condition of lean combustion is numerically investigated. The key geometrical parameters of the ribs and the ammonia/oxygen equivalence ratio are evaluated based on thermal performance and NOx emission performance. Finally, the sensitivity analysis of NO and related reaction pathways are analyzed under different equivalence ratios. The results show that increasing the height of the rib and decreasing the distance between the first rib and the inlet can effectively inhibit the generation of NO. Among all cases, the combustor with U-shaped ribs is observed the minimum mole fraction of NO at the outlet under the same working condition, which is 16% less comparing to the rectangular-shaped one. Besides, the mean wall temperature shows a weak correlation with NO emission. Increasing the equivalence ratio can help gain higher mean wall temperature, but at the same time promotes NOx production. This study is helpful to the design and improvement of micro-combustors fuelled by ammonia.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"144 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127218809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermoacoustic Stability Analysis of a Full-Annular Lean Combustor for Heavy-Duty Applications","authors":"D. Pampaloni, A. Andreini, A. Marini, G. Riccio, G. Ceccherini","doi":"10.1115/gt2021-59267","DOIUrl":"https://doi.org/10.1115/gt2021-59267","url":null,"abstract":"Thermoacoustic characterization of gas turbine combustion systems is of primary importance for successful development of gas turbine technology, to meet the stringent targets on pollutant emissions. In this context, it becomes more and more necessary to develop reliable tools to be used in the industrial design process. The dynamics of a lean-premixed full-annular combustor for heavy-duty applications has been numerically studied in this work. The well-established CFD-SI method has been used to investigate the flame response varying operational parameters such as the flame temperature (global equivalence ratio) and the fuel split between premixed and pilot fuel injections: such a wide range experimental characterization represents an opportunity to validate the employed numerical methods and to give a deeper insight into the flame dynamics. URANS simulations have been performed, due to their affordable computational costs from the industrial perspective, after validating their accuracy through the comparison against LES results. Furthermore, an approach where the pilot and the premixed flame responses are analyzed separately is proposed, exploiting the independence of their evolution. The calculated FTFs have been implemented in a 3D FEM model of the chamber, in order to perform linear stability analysis and to validate the numerical approach. A boundary condition for rotational periodicity based on Bloch-Wave theory has been implemented into the Helmholtz solver and validated against full-annular chamber simulations, allowing a significant reduction in computational time. The reliability of the numerical procedure has been assessed through the comparison against full-annular experimental results.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133661987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and Numerical Investigation on the Effect of Pressure On Micromix Hydrogen Combustion","authors":"D. Kroniger, Atsushi Horikawa, H. Funke, Franziska Pfaeffle, Tsuyoshi Kishimoto, Koichi Okada","doi":"10.1115/gt2021-58926","DOIUrl":"https://doi.org/10.1115/gt2021-58926","url":null,"abstract":"\u0000 The micromix (MMX) combustion concept is a DLN gas turbine combustion technology designed for high hydrogen content fuels. Multiple non-premixed miniaturized flames based on jet in cross-flow (JICF) are inherently safe against flashback and ensure a stable operation in various operative conditions.\u0000 The objective of this paper is to investigate the influence of pressure on the micromix flame with focus on the flame initiation point and the NOx emissions. A numerical model based on a steady RANS approach and the Complex Chemistry model with relevant reactions of the GRI 3.0 mechanism is used to predict the reactive flow and NOx emissions at various pressure conditions. Regarding the turbulence-chemical interaction, the Laminar Flame Concept (LFC) and the Eddy Dissipation Concept (EDC) are compared. The numerical results are validated against experimental results that have been acquired at a high pressure test facility for industrial can-type gas turbine combustors with regard to flame initiation and NOx emissions.\u0000 The numerical approach is adequate to predict the flame initiation point and NOx emission trends. Interestingly, the flame shifts its initiation point during the pressure increase in upstream direction, whereby the flame attachment shifts from anchoring behind a downstream located bluff body towards anchoring directly at the hydrogen jet. The LFC predicts this change and the NOx emissions more accurately than the EDC. The resulting NOx correlation regarding the pressure is similar to a non-premixed type combustion configuration.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130403866","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Computationally Efficient Method That Predicts Light-Around for Both Gas- and Liquid-Fueled Combustion","authors":"E. Meeks, C. Naik, G. Litrico, S. Rida","doi":"10.1115/gt2021-58770","DOIUrl":"https://doi.org/10.1115/gt2021-58770","url":null,"abstract":"\u0000 Controlling light-around and re-light presents design challenges for gas-turbine manufacturers. Researchers have studied the detailed phenomena in laboratory experiments to elucidate controlling factors and modes of behavior. Several groups have reported high-fidelity simulations of the fluid dynamics, turbulent mixing and light-around phenomena using large eddy simulations (LES) on highly refined computational meshes. While such simulations can reproduce experimental observations, they are computationally expensive and tend to be impractical for routine design analyses. In this work, we present a less computationally intensive CFD approach, which has been tested against laboratory experiments using both gaseous-fuel injections and liquid-fuel injections. Results show that a consistent practice of mesh and model settings can be used for all the test cases considered. The simulations generate light-around sequences and total-ignition times that agree well with experimental measurements. Observed trends are predicted when varying burner spacing as well as the fuel and injection method.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"205 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116219343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Investigation of the Confinement Effects in Radial-Radial Swirlers","authors":"Firat Kiyici, M. Perçin","doi":"10.1115/gt2021-58653","DOIUrl":"https://doi.org/10.1115/gt2021-58653","url":null,"abstract":"\u0000 This experimental study investigates the effect of confinement ratio (CR) on the flow field of a counter-rotating radial-radial swirler. Two-dimensional two-component (2D2C) particle image velocimetry (PIV) measurements are performed at the mid-plane of the jet. Four different confinement ratios (i.e., 10.4, 23.4, 41.6 and unconfined) are considered at a swirl number of 1.2. The results reveal the presence of a central toroidal recirculation zone (CTRZ) in all cases extending inside the jet which indicates the existence of an adverse pressure gradient. For the unconfined swirling jet, the recirculation zone is small in size and exists at the exit of the jet. For the CR = 41.6 case, on the other hand, there exist two separate recirculation zones with the first one being similar to the unconfined case in terms of size and axial position, while the second one being larger in size and positioned at a more downstream location. Variation of the axial velocity along the centerline of the jet for this case indicates the presence of an adverse pressure gradient only in the close-jet region correlated with the first recirculation zone. For the smaller CR values, a single massive CTRZ emerges. This leads to increase in the expansion angle of the swirling jet as the CR decreases. Correspondingly, the radial velocity at the jet exit increases. For the confined cases with a single recirculation zone, the length and the width to cross-section ratio increase with the CR. On the other hand, the ratio of the reverse flow rate to total mass flow rate decreases with increasing CR values.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114350318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"LES Based CFD Investigation of the Ignition Process in Lean Spray Burner","authors":"A. Andreini, M. Amerighi, L. Palanti, B. Facchini","doi":"10.1115/gt2021-59380","DOIUrl":"https://doi.org/10.1115/gt2021-59380","url":null,"abstract":"\u0000 During the last decades several new technologies were investigated in order to reduce the pollutant emissions and increase the overall engine efficiency. Unluckily, some of them including the lean direct injection spray combustion hinder the ignition performances of the combustor. Moreover, several expensive tests under very challenging operating conditions must be carried out to obtain the required certifications and assess the combustor behaviour with respect to the ignition process. Therefore, a deeper knowledge of the phenomena involved in the flame onset is mandatory to shorten the design process and achieve the required performances from the very beginning. In the last years, CFD simulations established as valid alternative to the experiments to investigate the complex phenomena involved in the ignition process. In fact, several examples are available in scientific literature about the use of simulations to predict the development of the flame starting from an initial kernel. In particular, LES proved to be a reliable tool to uncover new mechanisms of ignition and flame stabilization in gas turbines. In this work, two reactive LES of the ignition process were attempted using ANSYS Fluent 2019R1, with the aim of testing the Thickened Flame Model already implemented in the solver. In fact, compared to the previous versions, a new formulation for the efficiency function based on the pioneering work of Colin was made available. Such promising tool was validated against some detailed experimental results of a lean swirled flame, known as KIAI-CORIA spray flame. At first, a non-reactive and reactive LES were carried out to validate the cold field and the stabilized flame structure respectively. Finally, two ignition simulations were performed, from initial spark deposition up to flame stabilization or kernel quenching. All the obtained results have been extensively compared against the available experimental data showing that the employed simulation setup is fairly capable of describing the phenomena involved in the rig ignition.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129584343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Characterization of the Combustion in Fuel Flexible Humid Power Cycles","authors":"Simeon Dybe, F. Güthe, M. Bartlett, P. Stathopoulos, C. Paschereit","doi":"10.1115/gt2021-58675","DOIUrl":"https://doi.org/10.1115/gt2021-58675","url":null,"abstract":"\u0000 Modified humid power cycles provide the necessary boundary condition for combustion to operate on a wide fuel spectrum in a steam-rich atmosphere comprising hydrogen and syngas from gasification besides natural gas as fuels. Thus, these cycles with their high efficiency and flexibility fit in a carbon-free energy market dominated by renewable electricity generation, providing dispatchable heat and electric power.\u0000 To realize their full potential, the combustor utilized in such power cycles must fulfill the emission limits as well as demands of stable combustion over a wide range of fuel and steam ratios. The operation is limited by the risk of lean blowout for highly diluted syngas with low reactivity, and flashback for highly reactive hydrogen. Further, the gasification product gas can contain unwanted pollutants such as tars and nitrogen containing species like ammonia (NH3). Tars carry a considerable portion of the feedstock’s energy but are associated with detrimental operational behavior. The presence of ammonia in the combustion increases the risk of high NOx-emission at already small ammonia concentrations in the fuel.\u0000 In this work, humid hydrogen flames are analyzed for their stability and emissions. Stable hydrogen flames were produced over a wide equivalence ratio and steam ratio range at negligible NOx-emissions.\u0000 Further, natural gas, and a fuel blend substituting bio-syngas, was doped with ammonia. The combustion is analyzed with a focus on emissions and flame position and stability. The addition of ammonia causes high NOx-formation from fuel bound nitrogen (FBN), which highly increases NOx-emissions. The latter decrease with increasing NH3 content and increasing equivalence ratio.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134124357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}