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

{"title":"Study on the Non-Reacting Flowfield Characteristics of Lean Premixed Injector Modules With the Convergent Outlet","authors":"Fujun Sun, J. Suo, Luhua Guo","doi":"10.1115/gt2022-81682","DOIUrl":"https://doi.org/10.1115/gt2022-81682","url":null,"abstract":"\u0000 To form lifting flame and prevent auto-ignition and flashback, this paper proposed an original lean premixed injector with a convergent outlet. The influence of key structures (swirler-vanes angles, swirler-vanes profiles and premixing section lengths) on flowfield characteristics of lean premixed injector was investigated by the combination of laser diagnostic experiments and numerical simulations. The results show that there is a stable and sizeable detached central recirculation zone (CTRZ) downstream of the all six injectors and the detached distance from the convergent outlet decreases with the increase of the swirl number (SN) of the injector. With the increase of the swirler-vanes angle or the premixing section length, the SN of the injector increases, resulting in the CTRZ closer to the convergent outlet. Compared with the straight swirler-vanes, the SN of the curved swirler-vanes with the same angle is smaller, and the size of the its CTRZ is smaller and more backward. In addition, The peak value of the reflux ratio, which is also an important parameter to measure the flowfield characteristics, increases with the increase of the SN of the injectors.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122503499","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":"Operating Characteristics of a Flameless Combustor Obtained By Experiments Informed Modelling","authors":"Rishikesh Sampat, Niek Goselink, F. Schrijer, A. Gangoli Rao","doi":"10.1115/gt2022-81808","DOIUrl":"https://doi.org/10.1115/gt2022-81808","url":null,"abstract":"\u0000 Flameless Combustion is an interesting low NOx combustion technology for gas turbine engines. In order to design systems for stringent performance standards, it is important to understand emission formation in this regime. To this end, the characteristics of a combustor capable of operating in the Flameless regime are studied. Particle Image Velocimetry and thermocouple measurements were performed to obtain the velocity field and gas temperatures respectively, in the combustor under reacting conditions. Results from experiments were used to generate an “informed” chemical reactor network (CRN) model from which, temperature and species distributions were obtained. As such, this paper presents measured data and a methodology to combine it with CRN modelling to obtain gas composition and temperature. The temperature, NOx, CO and O2 mole fractions obtained at three different operating conditions shall be validated with gas composition measurements in the future.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128209333","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 Study on the Combustion Performance of Concentric Staged Lean Direct Injection Combustor With Two Different Swirler Angles of the Pilot Stage","authors":"P. Zhu, J. Suo","doi":"10.1115/gt2022-81895","DOIUrl":"https://doi.org/10.1115/gt2022-81895","url":null,"abstract":"\u0000 With the civil aviation engine now developing towards lower pollutant, and the lean direct injection (LDI) combustion proves excellent potential in reducing NOx emission, a concentric staged LDI combustor, both the main and pilot stages are based on LDI combustion concept, is proposed in this paper. It has great potential for an aero engine for a more straightforward structure and smaller size than the Multi-Point Lean Direct Injection (MPLDI) low emission combustor. Experimental research on the combustion and emission characteristics of the concentric staged LDI single-tube combustor with two swirl angles of the pilot stage (Case A: 35°, Case B: 45°) was carried out. The ignition performance was carried out at atmospheric pressure while the total pressure drop was 0.01–0.06, and the combustion and emission characteristics were carried out at different inlet conditions, fuel-air ratios (FAR), and fuel ratios of the main stage. The results indicate that the lowest ignition FAR of both two cases presents the trend of first decreasing and then increasing with the pressure drop, and Case B is lower than Case A at all conditions. The lean blowout FAR of Case B is 0.008, which is reduced by 11.11% than Case A. At the low condition, the inlet temperature is 540K, the NOx emission of the exit presents the trend of increasing with the increase of the FAR while the pilot stage works only. At the condition of the inlet temperature with 653K, both the main and pilot stages work together, and the fuel ratio has a distinct effect on the NOx emission of the combustor. However, when the inlet temperature is 737K, the EINOx of the combustor is almost the same at different fuel ratios. It is identical for both Case A and B. At all conditions, the EINOx of case B is lower than case A, and it is the same for the combustion efficiency. Overall consideration, though the combustion efficiency of Case B is lower than Case A, it is still not less than 99.9% when the main and pilot stages work simultaneously, 90% when the pilot stage works only. All the ignition, lean blowout, and NOx emission performances of Case B are better than A. Case B is better than Case A for a civil aviation engine.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"279 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124249370","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 Flow Characteristics of a Central-Staged Swirl Combustor","authors":"Xiangzhou Feng, J. Suo, P. Zhu, Yue Li, Qiandong Li","doi":"10.1115/gt2022-81552","DOIUrl":"https://doi.org/10.1115/gt2022-81552","url":null,"abstract":"\u0000 The two-combustion-zone design approach is adopted in order to achieve good idle LBO in a central-staged swirl combustor. The flow characteristics of the combustor are investigated through large eddy simulation (LES). The numerical method is validated by comparing the numerical results of time-average velocity profiles with PIV results at various axial locations. The grid scale is analyzed through Pope’s criterion to guarantee that most turbulent kinetic energy can be resolved by the present mesh. The coherent structures are isolated from turbulence flow by proper orthogonal decomposition (POD) method. Multiple monitor probs are set up in swirling flow and shear layers. The fast Fourier transform (FFT) is used to obtain frequency characteristic of time-domain signal. The difference between time-average velocity field and instantaneous velocity field is first explained. The recirculation zones are sorted by the locations and formation mechanism. The precessing vortex core (PVC) is found to be the crucial coherent structure of central-staged combustor. The spatial structure and temporal evolution of PVC are captured. Both single-helix and double-helix modes are discovered through POD method. By using phase-averaged method, the interaction between PVC and axial velocity field is investigated.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114748383","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 CH4-Humid Air Flame Characteristic of a Novel Micromix Concept Model Burner","authors":"Ce Liu, Weiwei Shao, Zhedian Zhang","doi":"10.1115/gt2022-81919","DOIUrl":"https://doi.org/10.1115/gt2022-81919","url":null,"abstract":"\u0000 The temperature and humidity of the combustion chamber inlet air under the humid air turbine cycle (HAT) vary dramatically, with the highest air temperature of approximately 900 K and high humidity of about 0.3 kg/kg. Compared with conventional lean premixed combustion, which may cause risks such as flashback and autoignition under high-temperature conditions, micromix combustion has the characteristics of small mixing scale, compact flame, flashback resistance, and low emissions, and has been implemented in HAT cycle combustion chambers. In this work, a 9-nozzle micromix model burner with a 3 × 3 array arrangement was designed based on the flow field organization of multiple micromix round jets. The effects of heat load (30∼55 kW), air temperature (300∼630 K), and steam ratio (0∼0.143 kg/kg) variation on the combustion and pollutant emission characteristics of methane-humid air micromix flame at atmospheric pressure conditions were experimentally investigated. Intensified Charge-Coupled Device (ICCD) is adopted to detect OH* chemiluminescence distribution thus investigating the turbulence-reaction interactions and the characteristics of the reaction field. And the effect of humidity on NOx emission was qualitatively analyzed by combining it with a reactor network model. Results indicated that compact flames were achieved for different cases with flame heights of about 85∼185 mm. The steam ratio has a significant influence on the flame structure and NOx emission. Compared with the dry air condition, the flame length increased by nearly 50% while the steam ratio reached 0.143 kg/kg, and the NOx emission was kept at a relatively low level of about 5 ppm (@15% O2) under the designed operating condition. The in-depth understanding of humid air micromix combustion technology is a significant step toward the design of future stability combustors for the HAT cycle.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"354 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124476849","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":"Lean Stability Limits and Exhaust Emissions of Ammonia-Methane-Air Swirl Flames at Micro Gas Turbine Relevant Pressure","authors":"C. Ávila, Guoqing Wang, Xuren Zhu, E. Es-sebbar, Marwan Abdullah, M. Younes, A. Jamal, T. Guiberti, W. Roberts","doi":"10.1115/gt2022-78304","DOIUrl":"https://doi.org/10.1115/gt2022-78304","url":null,"abstract":"\u0000 This study reports on the lean stability limits and exhaust emissions of ammonia-methane-air swirl flames with varied ammonia fuel fractions. A reduced-scale burner was manufactured, inspired by Ansaldo’s micro gas turbine AE-T100 burner, and it was installed inside a high-pressure combustion duct to operate at 4.5 bar. This pressure corresponds to that found at full-load in the actual micro gas turbine’s combustion chamber. The lean stability limits were measured by igniting the flame at an equivalence ratio of ϕ = 0.85 and then progressively decreasing the equivalence ratio until lean blowout. Emissions of CO2, NO, and N2O were recorded for different equivalence ratios and ammonia fractions. Rich flames at an equivalence ratio of ϕ = 1.20 were also considered. Results show that the equivalence ratio at lean blowout increases when the ammonia fraction increases and that all the ammonia fractions tested lead to flames more prone to lean blowout than the pure methane reference flame. The CO2 emissions are monotonically reduced by increasing the ammonia fraction, both for lean and rich flames. The NO emissions exceed many regulations limit regardless of the ammonia fraction for all lean equivalence ratios. N2O emissions are almost negligible, except for very lean equivalence ratios where the N2O mole fraction in the exhaust reaches unacceptably high values. Only rich ammonia-methane-air flames show good NO and N2O performance. Therefore, FTIR analysis was carried out to quantify the amount of the unburnt NH3 in the exhaust for these flames. Results show that unburnt NH3 concentration is invariant, around 200 ppmv, between 0.70 ≤ XNH3 ≤ 0.95. Data reported in this study provide insights for future work on combustors and after-treatment systems towards zero-emissions micro gas turbines.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128939042","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":"Ignition Chemistry of Syngas Highly Diluted in CO2","authors":"S. Cooper, O. Mathieu, D. J. Mohr, E. Petersen","doi":"10.1115/gt2022-81134","DOIUrl":"https://doi.org/10.1115/gt2022-81134","url":null,"abstract":"\u0000 Syngas is a desirable, high-hydrogen fuel source for combustors utilizing the Allam-Fetvedt cycle involving supercritical-CO2 (sCO2). Minimal data are available with high concentrations of CO2, with much of the available data being few in number and reported over very narrow temperature ranges. Considerable model disagreements have been shown at intermediate pressures (10–100 atm), while good agreement is seen for higher pressures (> 100 atm). Further examination of literature data highlights that the ignition delay time (IDT) characteristics of syngas at these pressures show little dependence on pressure, mixture composition, and equivalence ratio. To verify these observations, literature experiments were replicated using a high-pressure shock tube facility. Ignition delay time data were collected for syngas mixtures for pressures of 20 and 40 atm with 85% CO2 mixtures at stoichiometric conditions and H2:CO fuel ratios of 1:1 and 1:4. Literature results are limited to IDTs less than 500 μs, and data presented herein expand these data to considerably longer IDTs over a wider temperature range. Some disagreement with literature data is seen, and sources of discrepancy from the literature results are discussed. However, similar trends are seen for syngas ignition delay time characteristics and chemical kinetic models do not replicate this behavior. In particular, AramcoMech 2.0 replicates IDT near 40 atm for a H2:CO fuel ratio of 1:1, but is significantly under reactive for the 1:4 fuel ratio. To this end, a detailed sensitivity analysis using the AramcoMech 2.0 chemical kinetics mechanism highlights important chemical reactions. Of these reactions, significant model improvements are shown using the reaction rate suggested by Tsang and Hampson for CO+HO2 ⇌ CO2+OH.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127432845","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":"Validation of Hydrogen Boundary Layer Flashback Model on Gas Turbine Geometries and Conditions","authors":"S. Klein, Christos K. Sarakatsanis","doi":"10.1115/gt2022-79816","DOIUrl":"https://doi.org/10.1115/gt2022-79816","url":null,"abstract":"\u0000 Hydrogen is considered as a promising zero carbon battery fuel to deliver balancing power for the future electricity system with an increasing share of variable renewable power generation. Flame flashback is one of the main challenges for the application of hydrogen in gas turbines. Lean premixed hydrogen combustion is more prone to flashback than natural gas combustion due to higher flame speed and Lewis number effect.\u0000 The TU Delft developed a boundary layer flashback model based on a previous work by TU Munich. The TU Delft model includes amongst others the effect of the laminar flame speed, boundary layer profile, Lewis number and adverse pressure gradient of the mean flow. The model was successfully validated on academic experiments from TU Munich.\u0000 In the present paper the turbulent flame speed closure in the TU Delft flashback model is updated for gas turbine like conditions using experimental data from the University of California, Irvine (UCI). This updated model is validated against data from the Paul Scherrer Institute (PSI) and back tested on the original academic experiments from TU Munich.\u0000 The updated TU Delft boundary layer flashback model and the flashback model from the Paul Scherrer Institute (PSI) have been applied to a scaled version of the Flamesheet™ combustor. The outcome of the PSI flashback model correlates very well with test results from the TU Delft laboratory, the TU Delft flashback model only with the original flame speed correlation.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132480351","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 of an Open-Source Autonomous CFD Meta-Modeling Environment for Small-Scale Combustor Optimization – Part II","authors":"A. Briones, B. Rankin","doi":"10.1115/gt2022-78586","DOIUrl":"https://doi.org/10.1115/gt2022-78586","url":null,"abstract":"\u0000 This work presents an improved open-source autonomous CFD meta-modeling environment (OpenACME) for small-scale combustor design optimization. OpenACME couples several object-oriented programming open-source codes for CFD-assisted engineering design meta-modeling. OpenACME is fully automated and can be used in PC workstations or HPC clusters. OpenACME uses a global metaheuristic optimization algorithm based on multiple-objective evolutionary algorithm (i.e., NSGA-II). An initial design population is first computed with Latin Hypercube Sampling and subsequent iterations generate offspring based on tournament mating, uniform crossover, and polynomial mutation. OpenACME is capable of computing multiple parallel CFD design points concurrently, speeding up the meta-simulations. The CFD are based on steady-state, incompressible, three-dimensional simulations with multi-phase k-ω SST RANS and “frozen” flamelet progress variable (FFPV) combustion model. There are fifteen design variables. There are three meta-simulations. The meta-simulations report Pareto Frontier from which optimum designs can be selected based on thermodynamic cycle requirements. Conjugate heat transfer provides the most realistic liner temperature and combustor performance. Acritical is still recommended as a cost function when liner durability is a concern. OpenACME demonstrated to be a viable tool for combustor design optimization.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"177 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122435831","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":"Stress Blended Eddy Simulations for Hydrogen-Air Rotating Detonation Engine With Wall Heat Transfer","authors":"H. Elasrag, T. Gallagher, B. Rankin, S. Schumaker","doi":"10.1115/gt2022-81152","DOIUrl":"https://doi.org/10.1115/gt2022-81152","url":null,"abstract":"Hybrid stress blended eddy simulations (SBESs) are performed for the AFRL rotating detonation engine burner with detailed finite rate chemistry. The near wall boundary layer flow is modeled using URANS k-ω-SST model and the turbulent internal flow is modeled using Large Eddy Simulation (LES) dynamic Smagorinsky model. Using one-dimensional (1D) detonation tubes, the chemical mechanism and the chemistry integration algorithm are validated against the Chapman Jouguet (CJ) conditions and the Zel’dovich-von Neumann-DÖring (ZND) calculations with reasonably good accuracy. The impact of spatial and temporal resolutions on the wave propagation speed (WPS) and the von Neumann (VN) peak is studied using 1D detonation tube simulations. Using second order (SO) spatial accuracy, the SO temporal scheme over-predicts the VN peak with numerical dispersion near the pressure’s peak, while the first order (FO) temporal scheme is found to add the correct numerical dissipation. The SO and FO profiles show identical wave structure at different resolutions in the expansion region downstream of the compression shock’s peak. With FO temporal scheme, the VN peak was found to vary within 2%–6% band within a spatial resolution range of 0.5–0.001 mm and within 2%–20% band within a temporal resolution range of 1E−7 s – 1E−8 s. The spatial and temporal resolutions, however, are found to have a smaller impact on the WPS (varies within 2%–5%). For three-dimensional (3D) simulations the SO and FO comparisons with data were overall comparable. The results show very good agreement with the measurements mean static pressure data, WPS, specific thrust and specific impulse. The SO temporal scheme predicted a WPS with a mean error of approximately 11%–10% while the FO temporal scheme mean error is 6%. Back-flow due to the detonation wave in the air and fuel plenums are quantified to be 10% and 15%, respectively. The impact of wall heat transfer modeling on the detonation wave is studied. As the wall temperature increases more deflagration burning in the refill zone occurs ahead of the detonation wave. The fraction of heat released by deflagration and detonation is quantified for each case using cut-off values of 5 atm and 10 atm. Although the impact of wall heat transfer on WPS is found to be small, the fraction of heat released by deflagration increased by 10% for 600 K isothermal wall temperature compared to the 300 K isothermal wall temperature. For local static temperatures > 300 K, the fraction of heat released in the deflagration mode was 75%, 53%, and 40%, for the adiabatic walls, 600 K, and 300 K isothermal walls, respectively. The current numerical study shows that accurate wall heat transfer modeling is important for rotating detonation engine (RDE) numerical simulations.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128079140","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}