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

{"title":"Impact of Central Piloting on the Static and Dynamic Stability of Swirl-Stabilized Flames","authors":"Daniel G. Doleiden, Ashwini Karmarkar, J. O’Connor, J. Blust","doi":"10.1115/gt2022-80226","DOIUrl":"https://doi.org/10.1115/gt2022-80226","url":null,"abstract":"\u0000 One of the key challenges of lean, low-emissions combustor operation is flame stabilization, including both static and dynamic stabilization. Static flame stability encompasses a range of issues like flame holding, flashback, and blow-off. Dynamic flame stability refers to thermoacoustic combustion oscillations, which are driven by a coupling between combustor acoustics and flame heat release rate oscillations. Pilot flames are used as a passive means of achieving both static and dynamic stability in a number of gas turbine combustor technologies, likely by acting as a source of heat and radical species at the base of the main flame. Previous work used high-speed CH* chemiluminescence imaging to characterize the effect of a central pilot flame on the macrostructure and dynamic stability of a swirled lean-premixed natural gas-air main flame. In this study, the static and dynamic stability of the main flame are controlled by modifying the equivalence ratios of the main and pilot flames to better understand the mechanisms by which pilot flames enhance both static and dynamic stability. High-speed OH planar laser-induced fluorescence (OH-PLIF) is used to capture local instantaneous dynamics of the main and pilot flames across a range of operating conditions and stability outcomes, building upon the line-of-sight chemiluminescence analysis of the previous work. We find that the presence of the pilot flame controls anchoring of a relatively lean main flame. When the pilot flame is added to an unpiloted main flame, the main flame can rapidly change stabilization location, anchoring to the centerbody of the fuel injector. When a piloted main flame has the pilot removed, the flame lingers on the centerbody for a longer duration, likely due to the high-temperature boundary condition at the centerbody anchoring point. Further, the pilot flame mitigates combustion instability for a relatively broad range of operating conditions. Analysis of high-speed OH-PLIF shows that the main and pilot flames do not directly interact, and therefore the stabilizing mechanism of the pilot flame is indirect, as previously suggested.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"45 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":"127738230","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":"Improvement of the Primary Atomization Model for Jet Into Subsonic Crossflow","authors":"Hongyu Ju, J. Suo, Yue Li, L. Zheng","doi":"10.1115/gt2022-81654","DOIUrl":"https://doi.org/10.1115/gt2022-81654","url":null,"abstract":"\u0000 An improved primary atomization model for the jet-in-crossflow (JICF) atomization has been suggested and incorporated into the solver SprayFoam of OpenFOAM. The assumption of replacing jets with blobs, the maximum growth rate of the Kelvin-Helmholtz (K-H) wave, and its corresponding wavelength in the WAVE model are inherited. The present model assumes that the blobs move uniformly in the jet direction and accelerate uniformly in the crossflow direction to simulate the jet trajectory. It considers the Rayleigh-Taylor (R-T) wave on the liquid surface and assumes that the growth rate determines the R-T wave and K-H wave competition. The frequency, position, and mass of liquid surface breakup, the velocity, and the size of stripping drops are given in detail. Results of the present model have been compared with the experimental data in other literature under varying momentum flux ratios, Mach number, and air Weber number. The agreement between calculated results and the measured value is generally good, and a quantitative assessment of the model performance has been conducted.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"23 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":"126340737","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 I","authors":"A. Briones, B. Rankin","doi":"10.1115/gt2022-78581","DOIUrl":"https://doi.org/10.1115/gt2022-78581","url":null,"abstract":"\u0000 This work presents an open-source autonomous CFD meta-modeling environment (OpenACME) for small-scale combustor design optimization in a deterministic and continuous design space. OpenACME couples several object-oriented programming open-source codes for conjugate-heat transfer, steady-state, multiphase incompressible RANS CFD-assisted engineering design meta-modeling. There are fifteen design variables. Non-parametric rank regression (NPRR), global sensitivity analyses (GSA), and single-objective (SOO) optimization strategies are evaluated. The Euclidean distance (single-objective criterion) between a design point and the utopic point is based on the multi-objective criteria: combustion efficiency (η) maximization and pattern factor (PF), critical liner area factor (Acriticol), and total pressure loss (TPL) minimization. The SOO approach conducts Latin Hypercube Sampling for reacting flow CFD for subsequent local constraint optimization by linear interpolation. The local optimization successfully improves the initial design condition. The SOO approach is useful for guiding the design and development of future gas turbine combustors. NPRR and GSA indicate that there are no leading-order design variables controlling η, PF, Acritical, and TPL. Therefore, interactions between design variables control these output metrics because the output design space is inherently non-smooth and nonlinear. In summary, OpenACME is developed and demonstrated to be a viable tool for combustor design meta-modeling and optimization studies.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"30 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":"132556446","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":"Study on the Influence of Fuel Supply and Distribution on the Performance of Concentric Staged High Temperature Rise Combustor","authors":"Bo Sun, Wenya Song, J. Li","doi":"10.1115/gt2022-81692","DOIUrl":"https://doi.org/10.1115/gt2022-81692","url":null,"abstract":"\u0000 Based on the increasing demand for high thrust-to-weight ratio and high temperature rise of military aero-engines, a design scheme of combustor with concentric staged combustion organization is proposed. The main combustion stage of the swirler is a combination of swirling and non-swirling air intake. The verified one-dimensional calculation method is used to calculate and evaluate the performance of the combustion chamber. Based on the verification of three-dimensional numerical method and grid independence, the effects of fuel supply and distribution on combustor performance are studied. The studies show that the combustion efficiency and outlet temperature distribution could be improved when the axial position of the pilot nozzle is located at the outlet of vane channel. However, it will cause the problem that the high temperature flame is too close to the outlet of swirler. With the increase of the main nozzle angle, the combustion efficiency increases, and the overall temperature distribution factor (OTDF) decreases gradually. The fuel distribution ratio of main stage has a great impact on the field of temperature. The increase of fuel distribution ratio is contributed to improve the combustion efficiency and reduce the OTDF, while the total pressure loss coefficient increases slightly within a certain range. However, when the fuel distribution ratio exceeds 80%, the temperature near the baffle plate of dome is overheated, and the improvement effect of combustion efficiency is no longer obvious.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"202 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":"122028747","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":"Acoustic Flame Transfer Function Measurements in a Liquid Fueled High Pressure Aero-Engine Combustor","authors":"Krishna Venkatesan, Arin Cross, Fei Han","doi":"10.1115/gt2022-81769","DOIUrl":"https://doi.org/10.1115/gt2022-81769","url":null,"abstract":"\u0000 This paper describes an experimental approach and study of thermo-acoustic flame transfer functions in a high-pressure liquid-fueled rich burn combustor. The presence of high background flame luminosity in high-pressure sooty flame combustors precludes the application of any direct optical flame transfer function method. Instead, an acoustic method based on multiple microphones was employed to characterize the combustor acoustic pressure and velocity responses to acoustic forcing. A high-pressure siren device was employed to acoustically excite the combustor air flow over a broad range of frequencies from 150–1000Hz and modulate the combustor inlet dynamic pressure amplitudes. The acoustic pressures measured from the microphones located upstream and downstream of the flame were processed to obtain swirler impedances and flame transfer functions. Nonlinear behavior of the liquid fuel flame transfer function was studied by systematically varying the siren excitation pressure amplitudes. A parametric study of varying inlet air pressure, inlet air temperature, and thermal power was performed to study the impact of operating conditions on the measured liquid flame transfer function.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"21 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":"129613155","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 Prediction of a Lean Blow-Out Event of a Lab-Scale, Swirl-Stabilized Spray Flame","authors":"S. Ruoff, G. Eckel, P. Le Clercq, M. Aigner","doi":"10.1115/gt2022-81339","DOIUrl":"https://doi.org/10.1115/gt2022-81339","url":null,"abstract":"\u0000 Alternative jet fuels have a high potential to reduce emissions in aviation and to increase the independence from mineral oil. However, as a safe operation must be guaranteed, new fuels have to pass elaborate and expensive tests to be finally certified. To reduce the costs and time of the certification process, numerical simulations can be used to assess the impact of a new fuel on combustion. Further, the detailed simulations provide an insight into the fuel sensitive sub-processes. The lean blowout (LBO), i.e. the lower stability limit of a gas turbine combustor, is of primary concern for safe operation and the approval of alternative jet fuels. The paper at hand focuses on the formulation of a calculation protocol for the numerical representation of a lab-scale LBO experiment. The test case is a swirl-stabilized spray flame, which mimics several key features of aero-engine combustors. The LBO-limits are determined by a stepwise reduction of the fuel mass flow starting from a stable operation point above the measured blowout limit. Towards extinction, the heat release rate in the combustor drops. Furthermore, fuel is still evaporating, but less fuel is burned, leading to an accumulation of fuel in the combustion chamber. The blow-out is defined by a steep drop in heat release combined with a large increase of the gaseous fuel mass fraction in the computational domain. The semi-automated calculation protocol is able to successfully capture a blowout event at an equivalence ratio of ϕ = 0.32 and can thus be applied to evaluate alternative jet fuels in the future. In addition, a reignition event is observed for equivalence ratios slightly above ϕLBO.","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":"123971792","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 Computational Investigation of Wall-Film Formation by an Impinging Liquid Jet in Crossflow","authors":"G. Magnotti, Brandon A. Sforzo, C. Powell","doi":"10.1115/gt2022-80993","DOIUrl":"https://doi.org/10.1115/gt2022-80993","url":null,"abstract":"\u0000 Accurate fuel injection modeling remains of critical importance to the simulation of gas turbine engines as the predicted spray structure dictates fuel-air mixing, combustion, and emissions in the combustor. The prefilming airblast atomizer relies on the formation of a thin conical sheet of fuel, which breaks up due to its interaction with the counter-swirling airstreams. Recent x-ray imaging performed at Argonne National Laboratory’s Advanced Photon Source of a prefilming airblast atomizer revealed the formation of a frothy film, which is comprised of both liquid and bubbles. This finding challenges the inherent assumption for existing spray models, which assume that the film is only comprised of liquid fuel, and motivates the detailed investigation of the film formation process. To investigate the physics governing the impingement of a liquid jet in crossflow on a plate, a computational study was carried out. Large Eddy Simulations (LES) coupled with an algebraic volume-of-fluid (VOF) approach were performed to model a liquid water jet interacting with a subsonic crossflow and subsequently impinging on an aluminum plate. For the condition studied, a grid convergence study revealed that a minimum cell size of 25 μm was sufficient to adequately resolve the jet-wall interaction and film formation process, with good agreement with the x-ray measurements. These simulations also predicted the formation of bubbles within the film due to the entrainment of air. The influence of adhesion on the film characteristics and bubble distribution was explored using two different contact angles representing water on polished and unpolished aluminum plates. Although an increase in contact angle was not observed to affect the average film thickness, the lower interfacial tension reduced the number of bubbles that were formed, but increased the average size.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"46 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":"123795336","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":"Simultaneous Ultra-Small-Angle X-Ray Scattering and X-Ray Transmission Measurements of a Liquid Jet in Crossflow With Film Atomization","authors":"Brandon A. Sforzo, J. Ilavsky, C. Powell","doi":"10.1115/gt2022-82020","DOIUrl":"https://doi.org/10.1115/gt2022-82020","url":null,"abstract":"\u0000 Aircraft atomizers generally rely on multiple physical phenomena to introduce, distribute, and mix liquid fuel with the continuous air flow. Many such devices use plain jets for high liquid flow rates and film shear atomization to encourage droplet formation. To further characterize the near-field of processes, experiments were conducted to examine multiphase development of a liquid jet issuing into a subsonic crossflow. The jet impinged on a wall and the liquid subsequently filmed and convected downstream until reaching the end of the splitter plate, where it broke up by shear forces. X-ray diagnostics were used to interrogate different regions of the flow at the Advance Photon Source at Argonne National Laboratory 9-ID beamline. The projected liquid mass distribution was measured through x-ray absorption correlations using the collimated beam. The light was conditioned for Ultra-Small-Angle-X-ray-Scattering measurements, which were collected simultaneously with the transmission signal. These transmission and scattering signals were used to compute the projected mass and path-specific surface area of the spray, which were combined to calculate Satuer mean diameter. Though the transmission is typically collected using focused beam with a finer spatial resolution during a separate experimental campaign, the near-simultaneous acquisition allowed for more accurate registration between the signals and control of the operating condition. The transmission mapping confirmed the liquid path length of the unbroken liquid jet issuing into the domain and the interaction point with the wall. The spreading and flowing of the liquid down the plate and shedding from the trailing edge of the plate revealed an order of magnitude greater liquid path length, indicating the spreading of the film. X-ray scattering results indicate surface wave formation on the liquid jet and the initial stripping of droplets from the column. Furthermore, the scattering was enhanced for droplets rebounding due to splashing from the plate. The combined signals were used to calculate the droplet diameters in the shear breakup region trailing the splitter plate. These combined measurements provide detailed breakup information to inform inputs required to initialize Lagrangian spray calculations, as well as validate high-fidelity atomization simulations.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"20 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":"121074820","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":"Parameter Optimization of Combustor Dump Diffuser Based on RSM","authors":"Yue Yan, J. Suo, Yanhui Wu","doi":"10.1115/gt2022-80872","DOIUrl":"https://doi.org/10.1115/gt2022-80872","url":null,"abstract":"\u0000 At present, dump diffuser is basically adopted in the combustion chamber of aeroengine. The total pressure loss in it may account for 30% or even higher in the combustion chamber. So it is necessary to optimize various geometric parameters in dump diffuser. In order to solve the problem of increasing experimental cost due to multi-parameter optimization, response surface method (RSM) was used to study the performance of dump diffuser’s three geometric parameters at three inlet Mach numbers (Ma = 0.27, 0.20 and 0.10), namely pre-diffuser expansion angle, dump gap ratio and side wall expansion angle. The ratio of static pressure recovery coefficient to total pressure loss coefficient was used to compare the performance of the diffuser. Also the distribution of entropy production rate was used to obtain the pressure loss in the diffuser and analyze the causes. Then the response model was established and the response equation was solved to obtain the combined parameters corresponding to the optimal solution. Finally, the optimization results were predicted and verified. We can see that the influence of three geometric parameters on the diffuser performance is the prediffuser expansion angle, dump gap ratio and the side wall expansion angle in descending order. Compared with the initial average performance, the optimized results under three working conditions are improved by 47.93%, 48.70% and 69.49%, and the relative errors are all less than 6.5%, showing high accuracy.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"72 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":"114431727","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 Investigation on the Effect of Fuel Injection Location in a Multi-Swirl Lean Direct Injection Burner","authors":"Perikathra Sarath, Raparti Jogesh Aditya, T. Muruganandam","doi":"10.1115/gt2022-80762","DOIUrl":"https://doi.org/10.1115/gt2022-80762","url":null,"abstract":"\u0000 The lean direct injection (LDI) concept can potentially replace the existing combustion systems for future aircraft engines because of its low NOx emissions without compromising other parameters. A novel multi-swirl LDI burner1 with distributed fuel injection surrounded by airflow through multiple hexagonal swirlers of vane angle 45° was developed. The flow dynamics and combustion characteristics of three different fuel injection LDI configurations were compared using a three-dimensional (3D) computational fluid dynamic (CFD) study. Realizable k-ε turbulence model with a scalable wall function was adopted to get the flow features, distribution of velocity, pressure, and turbulent kinetic energy in the swirl burner, and combustion was parameterized by using non-premixed steady diffusion flamelet model with a PDF approach. Results obtained in the numerical model for temperatures and mole fractions of CO2, O2, and mass fraction of NOx show a behavior similar to that of the experimental model. Four types of flow structures were present in the flow field, and interaction of these structures plays an essential role in rapid mixing and flame stabilization. The numerical results showed that the LDI-2A burner achieved better mixing and had a lower flame temperature than the other two burners, which would improve flame stability and reduce the NOx emission.","PeriodicalId":121836,"journal":{"name":"Volume 3A: Combustion, Fuels, and Emissions","volume":"44 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":"126544308","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}