Michael van de Noort, Peter T. Ireland, Janendra C. Telisinghe
Abstract As aeroengine designers seek to raise Turbine Entry Temperatures for greater thermal efficiencies, novel cooling schemes are required to ensure that components can survive in increasingly hotter environments. By utilising a combination of impingement cooling, pin-fin cooling and effusion cooling, Double-Wall Effusion Cooling is well equipped to achieve the high metal cooling effectiveness required for such challenges whilst keeping coolant consumption at an acceptably low level. However, this high performance can drop-off within the variability of common manufacturing tolerances, which can also expose cooling schemes to issues such as hot gas ingestion. This paper uses an experimentally validated Low Order Flow Network Model (LOM) to assess the cooling performance of a Double Wall Effusion Cooling scheme employed in a High Pressure Turbine Nozzle Guide Vane, subject to the variability of geometric parameters set by their manufacturing tolerances. The relative significance of each geometric parameter is examined by varying it individually and comparing the effects on the cooling performance. A Monte Carlo analysis is then conducted to assess the likelihood of performance variation for a baseline design. Finally, multiple optimisation studies are conducted for the cooling scheme, with the simultaneous objectives of reducing coolant usage and maximising the design tolerances to reduce manufacturing cost, all whilst maintaining acceptable metal cooling effectiveness and backflow margins.
{"title":"Effects of Manufacturing Tolerances on Double Wall Effusion Cooling","authors":"Michael van de Noort, Peter T. Ireland, Janendra C. Telisinghe","doi":"10.1115/1.4063731","DOIUrl":"https://doi.org/10.1115/1.4063731","url":null,"abstract":"Abstract As aeroengine designers seek to raise Turbine Entry Temperatures for greater thermal efficiencies, novel cooling schemes are required to ensure that components can survive in increasingly hotter environments. By utilising a combination of impingement cooling, pin-fin cooling and effusion cooling, Double-Wall Effusion Cooling is well equipped to achieve the high metal cooling effectiveness required for such challenges whilst keeping coolant consumption at an acceptably low level. However, this high performance can drop-off within the variability of common manufacturing tolerances, which can also expose cooling schemes to issues such as hot gas ingestion. This paper uses an experimentally validated Low Order Flow Network Model (LOM) to assess the cooling performance of a Double Wall Effusion Cooling scheme employed in a High Pressure Turbine Nozzle Guide Vane, subject to the variability of geometric parameters set by their manufacturing tolerances. The relative significance of each geometric parameter is examined by varying it individually and comparing the effects on the cooling performance. A Monte Carlo analysis is then conducted to assess the likelihood of performance variation for a baseline design. Finally, multiple optimisation studies are conducted for the cooling scheme, with the simultaneous objectives of reducing coolant usage and maximising the design tolerances to reduce manufacturing cost, all whilst maintaining acceptable metal cooling effectiveness and backflow margins.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136296292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Particle image velocimetry (PIV) measurements in the blade-to-blade (B2B) plane and cascade outlet plane (COP) of a high-speed low-pressure turbine (LPT) cascade were performed at engine-representative outlet Mach number (0.70-0.95), and Reynolds number (70k-120k) under steady flow conditions. The freestream turbulence characteristics were imposed by means of a passive turbulence grid. The PIV results on the B2B plane were compared against five-hole probe (5HP) and Reynolds-averaged Navier-Stokes (RANS) computations to assess the validity of measurement and simulation techniques in the engine-relevant LPT cascade flows. The PIV captured the wake depth and width measured by the 5HP whereas the RANS displayed an overprediction of the wake Mach number deficit. The 5HP was found to impose sinewave fluctuations of the measured flow angle downstream, around three times higher than PIV. Additionally, PIV estimated turbulence intensity (TI) in the cascade, showing TI decay along a streamline. At the highest Mach number, a peak TI occurred past a shock wave. Measurements of the outlet flow field highlighted a high TI in the secondary flow region whereas high degree of anisotropy (DA) was registered in the boundary of the secondary flow and freestream regions. The contribution of the streamwise fluctuation component was found to be less than the crosswise and radial components in the freestream region. Increasing the cascade outlet Mach number, the contribution of streamwise fluctuation to the DA was observed to decrease.
{"title":"PIV MEASUREMENTS IN A HIGH-SPEED LOW-REYNOLDS LOW-PRESSURE TURBINE CASCADE","authors":"Mizuki Okada, Loris Simonasis, Gustavo Lopes, Sergio Lavagnoli","doi":"10.1115/1.4063674","DOIUrl":"https://doi.org/10.1115/1.4063674","url":null,"abstract":"Abstract Particle image velocimetry (PIV) measurements in the blade-to-blade (B2B) plane and cascade outlet plane (COP) of a high-speed low-pressure turbine (LPT) cascade were performed at engine-representative outlet Mach number (0.70-0.95), and Reynolds number (70k-120k) under steady flow conditions. The freestream turbulence characteristics were imposed by means of a passive turbulence grid. The PIV results on the B2B plane were compared against five-hole probe (5HP) and Reynolds-averaged Navier-Stokes (RANS) computations to assess the validity of measurement and simulation techniques in the engine-relevant LPT cascade flows. The PIV captured the wake depth and width measured by the 5HP whereas the RANS displayed an overprediction of the wake Mach number deficit. The 5HP was found to impose sinewave fluctuations of the measured flow angle downstream, around three times higher than PIV. Additionally, PIV estimated turbulence intensity (TI) in the cascade, showing TI decay along a streamline. At the highest Mach number, a peak TI occurred past a shock wave. Measurements of the outlet flow field highlighted a high TI in the secondary flow region whereas high degree of anisotropy (DA) was registered in the boundary of the secondary flow and freestream regions. The contribution of the streamwise fluctuation component was found to be less than the crosswise and radial components in the freestream region. Increasing the cascade outlet Mach number, the contribution of streamwise fluctuation to the DA was observed to decrease.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135481008","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nathanael Wendel, Noah Subasic, Andrew Mizer, Jeffrey Bons
Abstract In this paper the role of mineral composition was assessed for Air Force Research Laboratory test dust (AFRL), for deposition in a realistic gas turbine engine environment. Experiments were performed on an effusion cooling test article with a coolant flow temperature of 894K and surface temperature of 1144K. Aerosolized dust with a 0-10 μm particle size distribution was delivered to the test article. The mineral recipe of AFRL was altered such that the presence of each of the five components ranged from 0% to 100%, and capture efficiency, hole capture efficiency, blockage per gram, and normalized deposit height were reported. Results are compared to a previous study of the inter-mineral synergies in an impingement cooling jet at the same temperature conditions. Despite differences in experimental facility flow geometry, overall agreement was found between the trends in deposition behavior of the dust blends. The strong deposition effects that were observed were shown to be related to adhesion forces of particles, mechanical properties, and chemical properties of the dust minerals. Supplemental testing was performed in a high-temperature (1425–1650 K) impinging jet (200–260 m/s) to evaluate mineral effects at hot gas path conditions. Capture efficiency and morphology of dust deposits are reported. The capture efficiency in this regime was shown to correlate well with temperature, with secondary chemical effects. An attempt was made to predict capture efficiency using chemical assessments such as ratio of bases to acids, Ca:Si ratio, and optical basicity with only modest success.
{"title":"MINERAL COMPOSITION EFFECTS ON DUST DEPOSITION AT REALISTIC ENGINE CONDITIONS","authors":"Nathanael Wendel, Noah Subasic, Andrew Mizer, Jeffrey Bons","doi":"10.1115/1.4063675","DOIUrl":"https://doi.org/10.1115/1.4063675","url":null,"abstract":"Abstract In this paper the role of mineral composition was assessed for Air Force Research Laboratory test dust (AFRL), for deposition in a realistic gas turbine engine environment. Experiments were performed on an effusion cooling test article with a coolant flow temperature of 894K and surface temperature of 1144K. Aerosolized dust with a 0-10 μm particle size distribution was delivered to the test article. The mineral recipe of AFRL was altered such that the presence of each of the five components ranged from 0% to 100%, and capture efficiency, hole capture efficiency, blockage per gram, and normalized deposit height were reported. Results are compared to a previous study of the inter-mineral synergies in an impingement cooling jet at the same temperature conditions. Despite differences in experimental facility flow geometry, overall agreement was found between the trends in deposition behavior of the dust blends. The strong deposition effects that were observed were shown to be related to adhesion forces of particles, mechanical properties, and chemical properties of the dust minerals. Supplemental testing was performed in a high-temperature (1425–1650 K) impinging jet (200–260 m/s) to evaluate mineral effects at hot gas path conditions. Capture efficiency and morphology of dust deposits are reported. The capture efficiency in this regime was shown to correlate well with temperature, with secondary chemical effects. An attempt was made to predict capture efficiency using chemical assessments such as ratio of bases to acids, Ca:Si ratio, and optical basicity with only modest success.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134976055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Increasing turbine inlet temperature is beneficial to enhance turbine performance. However, this also results in stringent cooling requirements. Unlike turbines in air cycle machines, the partial admission axial impulse turbines for underwater vehicles can utilize the abundant seawater as the cooling medium. In addition, the short blades cannot accommodate the complex cooling channels used in aero-engines, and the alternative way is jet impingement liquid cooling. This paper proposes a fluid–thermal–structural coupling method to investigate the performance of partial admission axial impulse turbines with water-cooling on the rotating wheel front surface. The volume of fluid multiphase model is employed to study the transient gas–liquid interaction, while the Lee model is chosen to model the heat and mass transfer during phase change. Also, a two-way weakly coupling method among fluid, thermal, and structure is utilized to account for fluid–structure interaction. The results show that the temperature distribution at the turbine wheel drops significantly with the jet impingement liquid cooling. The turbine efficiency is also reduced by 3.38% due to the mixing of cooling medium and gas. From stress analysis, the use of water-cooling can minimize turbine damage and ensure stable turbine operation. This study provides insight into the cooling method for partial admission axial impulse turbines for the underwater vehicle.
{"title":"Fluid-thermal-structural Analysis of Partial Admission Axial Impulse Turbines with Liquid Jet Impingement Cooling","authors":"Hanwei Wang, Kai Luo, Ruoyang Zhi, Kan Qin","doi":"10.1115/1.4063410","DOIUrl":"https://doi.org/10.1115/1.4063410","url":null,"abstract":"Abstract Increasing turbine inlet temperature is beneficial to enhance turbine performance. However, this also results in stringent cooling requirements. Unlike turbines in air cycle machines, the partial admission axial impulse turbines for underwater vehicles can utilize the abundant seawater as the cooling medium. In addition, the short blades cannot accommodate the complex cooling channels used in aero-engines, and the alternative way is jet impingement liquid cooling. This paper proposes a fluid–thermal–structural coupling method to investigate the performance of partial admission axial impulse turbines with water-cooling on the rotating wheel front surface. The volume of fluid multiphase model is employed to study the transient gas–liquid interaction, while the Lee model is chosen to model the heat and mass transfer during phase change. Also, a two-way weakly coupling method among fluid, thermal, and structure is utilized to account for fluid–structure interaction. The results show that the temperature distribution at the turbine wheel drops significantly with the jet impingement liquid cooling. The turbine efficiency is also reduced by 3.38% due to the mixing of cooling medium and gas. From stress analysis, the use of water-cooling can minimize turbine damage and ensure stable turbine operation. This study provides insight into the cooling method for partial admission axial impulse turbines for the underwater vehicle.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135547280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Herringbone grooved journal bearings (HGJBs) are widely used in micro-turbocompressor applications due to their high load-carrying capacity, low friction, and oil-free solution. However, the performance of these bearings is sensitive to manufacturing deviations, which can lead to significant variations in their performance and stability. In this study, design guidelines for robust design against manufacturing deviations of HGJB supported micro-turbocompressors are proposed. These guidelines are based on surrogate model-assisted multi-objective optimization using ensembles of artificial neural networks trained on a large dataset of rotor and bearing designs as well as operating conditions. The developed framework is then applied to a series of case studies representative of heat-pump and fuel-cell micro-turbomachines. To highlight the importance of rotor geometry and bearing aspect ratio in the robustness of HGJBs, two types of optimizations are performed: one focusing on optimizing the bearing geometry, and the other focusing on both the bearing and rotor geometries. The analysis of the Pareto fronts and Pareto optima of each type of optimization and case study allows for the derivation of design guidelines for the robust design of HGJB supported rotors. Results suggest that by following these guidelines, it is possible to significantly improve the robustness of herringbone grooved journal bearings against manufacturing deviations, resulting in stable operation. The best design achieved ±8 μm tolerance on the bearing clearance, and designs optimized for both rotor and bearing geometry outperformed those optimized for bearing geometry alone. This work successfully identifies guidelines for the robust design of herringbone grooved journal bearings in micro-turbocompressor applications, demonstrating the strength of surrogate model-assisted multi-objective optimization. It provides a valuable tool for engineers seeking to optimize the performance and reliability of these bearings.
{"title":"ROBUST DESIGN OF HERRINGBONE GROOVED JOURNAL BEARINGS USING MULTI-OBJECTIVE OPTIMIZATION WITH ARTIFICIAL NEURAL NETWORKS","authors":"Soheyl Massoudi, Jurg Schiffmann","doi":"10.1115/1.4063392","DOIUrl":"https://doi.org/10.1115/1.4063392","url":null,"abstract":"Abstract Herringbone grooved journal bearings (HGJBs) are widely used in micro-turbocompressor applications due to their high load-carrying capacity, low friction, and oil-free solution. However, the performance of these bearings is sensitive to manufacturing deviations, which can lead to significant variations in their performance and stability. In this study, design guidelines for robust design against manufacturing deviations of HGJB supported micro-turbocompressors are proposed. These guidelines are based on surrogate model-assisted multi-objective optimization using ensembles of artificial neural networks trained on a large dataset of rotor and bearing designs as well as operating conditions. The developed framework is then applied to a series of case studies representative of heat-pump and fuel-cell micro-turbomachines. To highlight the importance of rotor geometry and bearing aspect ratio in the robustness of HGJBs, two types of optimizations are performed: one focusing on optimizing the bearing geometry, and the other focusing on both the bearing and rotor geometries. The analysis of the Pareto fronts and Pareto optima of each type of optimization and case study allows for the derivation of design guidelines for the robust design of HGJB supported rotors. Results suggest that by following these guidelines, it is possible to significantly improve the robustness of herringbone grooved journal bearings against manufacturing deviations, resulting in stable operation. The best design achieved ±8 μm tolerance on the bearing clearance, and designs optimized for both rotor and bearing geometry outperformed those optimized for bearing geometry alone. This work successfully identifies guidelines for the robust design of herringbone grooved journal bearings in micro-turbocompressor applications, demonstrating the strength of surrogate model-assisted multi-objective optimization. It provides a valuable tool for engineers seeking to optimize the performance and reliability of these bearings.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135547410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhihui Li, Francesco Montomoli, Nicola Casari, Michele Pinelli
Abstract In this work, a new multifidelity (MF) uncertainty quantification (UQ) framework is presented and applied to the LS89 nozzle modified by fouling. Geometrical uncertainties significantly influence the aerodynamic performance of gas turbines. One representative example is given by the airfoil shape modified by fouling deposition, as in turbine nozzle vanes, which generates high-dimensional input uncertainties. However, the traditional UQ approaches suffer from the curse of dimensionality phenomenon in predicting the influence of high-dimensional uncertainties. Thus, a new approach based on multifidelity deep neural networks (MF-DNN) was proposed in this paper to solve the high-dimensional UQ problem. The basic idea of MF-DNN is to ensure the approximation capability of neural networks based on abundant low-fidelity (LF) data and few high-fidelity (HF) data. The prediction accuracy of MF-DNN was first evaluated using a 15-dimensional benchmark function. An affordable turbomachinery UQ platform was then built based on key components including the MF-DNN model, the sampling module, the parameterization module and the statistical processing module. The impact of fouling deposition on LS89 nozzle vane flow was investigated using the proposed UQ framework. In detail, the MF-DNN was fine-tuned based on bi-level numerical simulation results: the 2D Euler flow field as low-fidelity data and the 3D Reynolds-averaged Navier–Stokes (RANS) flow field as high-fidelity data. The UQ results show that the total pressure loss of LS89 vane is increased by at most 17.1% or reduced by at most 4.3%, while the mean value of the loss is increased by 3.4% compared to the baseline. The main reason for relative changes in turbine nozzle performance is that the geometric uncertainties induced by fouling deposition significantly alter the intensity of shock waves near the throat area and trailing edge. The developed UQ platform could provide a useful tool in the design and optimization of advanced turbomachinery considering high-dimensional input uncertainties.
{"title":"HIGH-DIMENSIONAL UNCERTAINTY QUANTIFICATION OF HIGH-PRESSURE TURBINE VANE BASED ON MULTI-FIDELITY DEEP NEURAL NETWORKS","authors":"Zhihui Li, Francesco Montomoli, Nicola Casari, Michele Pinelli","doi":"10.1115/1.4063391","DOIUrl":"https://doi.org/10.1115/1.4063391","url":null,"abstract":"Abstract In this work, a new multifidelity (MF) uncertainty quantification (UQ) framework is presented and applied to the LS89 nozzle modified by fouling. Geometrical uncertainties significantly influence the aerodynamic performance of gas turbines. One representative example is given by the airfoil shape modified by fouling deposition, as in turbine nozzle vanes, which generates high-dimensional input uncertainties. However, the traditional UQ approaches suffer from the curse of dimensionality phenomenon in predicting the influence of high-dimensional uncertainties. Thus, a new approach based on multifidelity deep neural networks (MF-DNN) was proposed in this paper to solve the high-dimensional UQ problem. The basic idea of MF-DNN is to ensure the approximation capability of neural networks based on abundant low-fidelity (LF) data and few high-fidelity (HF) data. The prediction accuracy of MF-DNN was first evaluated using a 15-dimensional benchmark function. An affordable turbomachinery UQ platform was then built based on key components including the MF-DNN model, the sampling module, the parameterization module and the statistical processing module. The impact of fouling deposition on LS89 nozzle vane flow was investigated using the proposed UQ framework. In detail, the MF-DNN was fine-tuned based on bi-level numerical simulation results: the 2D Euler flow field as low-fidelity data and the 3D Reynolds-averaged Navier–Stokes (RANS) flow field as high-fidelity data. The UQ results show that the total pressure loss of LS89 vane is increased by at most 17.1% or reduced by at most 4.3%, while the mean value of the loss is increased by 3.4% compared to the baseline. The main reason for relative changes in turbine nozzle performance is that the geometric uncertainties induced by fouling deposition significantly alter the intensity of shock waves near the throat area and trailing edge. The developed UQ platform could provide a useful tool in the design and optimization of advanced turbomachinery considering high-dimensional input uncertainties.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135547412","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Filtered Rayleigh scattering (FRS) is a non-intrusive, laser-based optical technique for measuring 3-component velocity, static temperature, and static density with high spatial resolution and low uncertainty. FRS can be used to derive total values as well as turbomachinery efficiencies. The Virginia Tech team has been developing this seedless technique for simultaneous planar (or line) measurements to overcome the limitations associated with seed-based laser measurement techniques such as laser Doppler velocimetry (LDV), particle image velocimetry (PIV), and Doppler global velocimetry (DGV) as well as limitations with physical probe rakes such as blockage and wake production. This technique is especially attractive in flow cases or environments where the aforementioned seed-based laser measurement techniques are limited or not possible. A combination of specially designed boundary layer total pressure probe rake measurements, FRS optical rake measurements, and computational fluid dynamics (CFD) results in the inlet of a Honeywell TFE731-2 turbofan are presented. Results show that all three techniques (FRS, probe, and CFD) match within approximately 2% root-mean-square error (RMSE). Inlet efficiency was derived and found to be within 2.3% difference for all three techniques.
{"title":"VALIDATION OF FILTERED RAYLEIGH SCATTERING OPTICAL RAKE MEASUREMENT TECHNIQUES IN TURBOMACHINERY APPLICATIONS AND BOUNDARY LAYERS","authors":"Sean Powers, Gwibo Byun, K. Todd Lowe","doi":"10.1115/1.4063562","DOIUrl":"https://doi.org/10.1115/1.4063562","url":null,"abstract":"Abstract Filtered Rayleigh scattering (FRS) is a non-intrusive, laser-based optical technique for measuring 3-component velocity, static temperature, and static density with high spatial resolution and low uncertainty. FRS can be used to derive total values as well as turbomachinery efficiencies. The Virginia Tech team has been developing this seedless technique for simultaneous planar (or line) measurements to overcome the limitations associated with seed-based laser measurement techniques such as laser Doppler velocimetry (LDV), particle image velocimetry (PIV), and Doppler global velocimetry (DGV) as well as limitations with physical probe rakes such as blockage and wake production. This technique is especially attractive in flow cases or environments where the aforementioned seed-based laser measurement techniques are limited or not possible. A combination of specially designed boundary layer total pressure probe rake measurements, FRS optical rake measurements, and computational fluid dynamics (CFD) results in the inlet of a Honeywell TFE731-2 turbofan are presented. Results show that all three techniques (FRS, probe, and CFD) match within approximately 2% root-mean-square error (RMSE). Inlet efficiency was derived and found to be within 2.3% difference for all three techniques.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135344959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jared Kerestes, Christopher Marks, John Clark, J. Mitch Wolff, Ron-Ho (Bob) Ni, Nathan Fletcher
Abstract Over the years, computational fluids dynamics (CFD) has matured to such a state so as to be indispensable in turbine design. In the past two decades, significant advances in turbine design have been made through the use of CFD—in particular, through the use of Reynolds-Averaged Navier-Stokes (RANS) simulations. Currently, turbine design is RANS-driven; however, significant gains in performance and efficiency are becoming more difficult to achieve using RANS. For this reason, the turbomachinery CFD community is moving toward Large-Eddy Simulations (LES). In the design of low-pressure turbine (LPT) blades, LES is particularly beneficial owing to its ability to capture accurately both transition and separation. In this paper, LES is used to characterize a new family of high-lift high-work LPT blades—designated the LXFHW-LS family—designed at the U.S. Air Force Research Laboratory (AFRL). LES simulations are conducted in accordance with the methodology outlined in Part I of this paper. The purpose of this paper is twofold: 1) to use LES to predict the performance of the LXFHW-LS family and compare to measurements in a low-speed linear cascade and, in doing so, 2) to illustrate how LES may be used in LPT design as it evolves from RANS-driven to LES-driven. For each blade in the family, the loading distribution and loss coefficient are computed for sixteen separate Reynolds numbers. Computational results are validated using detailed experimental measurements from a low-speed linear cascade wind tunnel.
多年来，计算流体动力学(CFD)已经成熟到涡轮设计中不可缺少的程度。在过去的二十年中，通过使用cfd，特别是通过使用reynolds - average Navier-Stokes (RANS)模拟，涡轮设计取得了重大进展。目前，涡轮设计是ranss驱动的;然而，性能和效率的显著提高越来越难以使用ran实现。因此，涡轮机械CFD界正在向大涡模拟(LES)方向发展。在低压涡轮(LPT)叶片的设计中，LES特别有用，因为它能够准确地捕获过渡和分离。在本文中，LES被用于表征由美国空军研究实验室(AFRL)设计的一种新的高升力高功LPT叶片系列——LXFHW-LS系列。LES模拟是根据本文第一部分概述的方法进行的。本文的目的有两个:1)使用LES来预测LXFHW-LS系列的性能，并与低速线性级联中的测量结果进行比较，在此过程中，2)说明LES如何在LPT设计中使用，因为它从rans驱动发展到LES驱动。对于该系列中的每个叶片，计算了16个独立雷诺数的载荷分布和损失系数。通过低速线性叶栅风洞的详细实验测量，验证了计算结果。
{"title":"LES MODELING OF HIGH-LIFT HIGH-WORK LPT BLADES: PART II—VALIDATION AND APPLICATION","authors":"Jared Kerestes, Christopher Marks, John Clark, J. Mitch Wolff, Ron-Ho (Bob) Ni, Nathan Fletcher","doi":"10.1115/1.4063509","DOIUrl":"https://doi.org/10.1115/1.4063509","url":null,"abstract":"Abstract Over the years, computational fluids dynamics (CFD) has matured to such a state so as to be indispensable in turbine design. In the past two decades, significant advances in turbine design have been made through the use of CFD—in particular, through the use of Reynolds-Averaged Navier-Stokes (RANS) simulations. Currently, turbine design is RANS-driven; however, significant gains in performance and efficiency are becoming more difficult to achieve using RANS. For this reason, the turbomachinery CFD community is moving toward Large-Eddy Simulations (LES). In the design of low-pressure turbine (LPT) blades, LES is particularly beneficial owing to its ability to capture accurately both transition and separation. In this paper, LES is used to characterize a new family of high-lift high-work LPT blades—designated the LXFHW-LS family—designed at the U.S. Air Force Research Laboratory (AFRL). LES simulations are conducted in accordance with the methodology outlined in Part I of this paper. The purpose of this paper is twofold: 1) to use LES to predict the performance of the LXFHW-LS family and compare to measurements in a low-speed linear cascade and, in doing so, 2) to illustrate how LES may be used in LPT design as it evolves from RANS-driven to LES-driven. For each blade in the family, the loading distribution and loss coefficient are computed for sixteen separate Reynolds numbers. Computational results are validated using detailed experimental measurements from a low-speed linear cascade wind tunnel.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135536455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thorsten Hansen, Erik Munktell, Georg Scheuerer, Qingyuan Zhuang, Kim Zwiener
Abstract Behr et al. [1] have experimentally investigated the unsteady-state flow and clocking effects in a 1.5-stage high-work turbine. Their test rig had a first stator row with 36 blades, a 54-bladed rotor at 2,700 rpm, and a second stator row with 36 blades. They studied four different stator-clocking positions. The present paper computationally investigates the unsteady-state flow through the 1.5-stage turbine by performing CFD simulations with the Simcenter STAR-CCM+ software. The mathematical model of the simulations consisted of the ensemble-averaged unsteady-state mass, momentum and energy equations complemented by the SST turbulence model. The authors applied a quality assessment procedure to the computational results before comparing them to the experimental data. They reported the numerical accuracy using the Grid Convergence Index (GCI). The results showed an increase in the calculated efficiencies of the unsteady-state over the steady-state results, bringing data and simulations closer. The total pressure contours at the rotor and second stator exit planes also agreed well with the experiments. Finally, the paper includes simulations of the effects of different stator-clocking positions. The results showed a similar response to the change in stator-clocking position as the experiments.
{"title":"CFD SIMULATIONS OF THE UNSTEADY-STATE FLOW THROUGH A 1.5-STAGE HIGH-WORK TURBINE","authors":"Thorsten Hansen, Erik Munktell, Georg Scheuerer, Qingyuan Zhuang, Kim Zwiener","doi":"10.1115/1.4063516","DOIUrl":"https://doi.org/10.1115/1.4063516","url":null,"abstract":"Abstract Behr et al. [1] have experimentally investigated the unsteady-state flow and clocking effects in a 1.5-stage high-work turbine. Their test rig had a first stator row with 36 blades, a 54-bladed rotor at 2,700 rpm, and a second stator row with 36 blades. They studied four different stator-clocking positions. The present paper computationally investigates the unsteady-state flow through the 1.5-stage turbine by performing CFD simulations with the Simcenter STAR-CCM+ software. The mathematical model of the simulations consisted of the ensemble-averaged unsteady-state mass, momentum and energy equations complemented by the SST turbulence model. The authors applied a quality assessment procedure to the computational results before comparing them to the experimental data. They reported the numerical accuracy using the Grid Convergence Index (GCI). The results showed an increase in the calculated efficiencies of the unsteady-state over the steady-state results, bringing data and simulations closer. The total pressure contours at the rotor and second stator exit planes also agreed well with the experiments. Finally, the paper includes simulations of the effects of different stator-clocking positions. The results showed a similar response to the change in stator-clocking position as the experiments.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135535237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An experimental study was performed on the discharge coefficients of laidback fan-shaped holes under different internal coolant crossflow orientations. The influence of the geometric and flow parameters on the discharge coefficient was investigated under flat plate conditions, where the pressure ratio ranged from 1–1.6. The results show that the film hole discharge coefficient is more sensitive to variations in the coolant crossflow under small pressure ratios. In comparison, the discharge coefficient is much less sensitive to the change of coolant crossflow under high pressure. Meanwhile, the length of the cylindrical section varied over the range of 1D–4D, and the length of the expansion section varied from 2D–6D, where D represents the diameter of the film hole. The results show that the discharge coefficient is much more sensitive to the length of the cylindrical section than to the length of the expansion section. To quantify the sensitivity of the internal crossflow effects on the discharge coefficient, a low-ordered reduced model is proposed for the discharge coefficient of laidback fan-shaped holes. Both the geometric and flow parameters are considered in the model and give prediction errors within 5%.
{"title":"Sensitivity of laidback fan-shaped hole discharge coefficient under internal coolant crossflow conditions","authors":"Haoyang Liu, Qiang Du, Qingzong Xu, Guangyao Xu, Hongye Li, Dawei Chen","doi":"10.1115/1.4063366","DOIUrl":"https://doi.org/10.1115/1.4063366","url":null,"abstract":"\u0000 An experimental study was performed on the discharge coefficients of laidback fan-shaped holes under different internal coolant crossflow orientations. The influence of the geometric and flow parameters on the discharge coefficient was investigated under flat plate conditions, where the pressure ratio ranged from 1–1.6. The results show that the film hole discharge coefficient is more sensitive to variations in the coolant crossflow under small pressure ratios. In comparison, the discharge coefficient is much less sensitive to the change of coolant crossflow under high pressure. Meanwhile, the length of the cylindrical section varied over the range of 1D–4D, and the length of the expansion section varied from 2D–6D, where D represents the diameter of the film hole. The results show that the discharge coefficient is much more sensitive to the length of the cylindrical section than to the length of the expansion section. To quantify the sensitivity of the internal crossflow effects on the discharge coefficient, a low-ordered reduced model is proposed for the discharge coefficient of laidback fan-shaped holes. Both the geometric and flow parameters are considered in the model and give prediction errors within 5%.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41963390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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