With increasing requirements for high-loading and high-efficiency turbomachines, blades become thinner and thinner and thus design optimizations considering both aerodynamic performances and aeroelastic stability become more and more necessary. In this study, a full viscosity discrete adjoint harmonic balance (HB) solver has been developed using algorithmic differentiation (AD), verified by a discrete linear solver based upon duality property, and then adopted to perform multi-disciplinary coupled design optimizations. To this end, a framework of multi-objective adjoint design optimizations has been developed to improve both aerodynamic performances and aeroelastic stability of turbomachinery blades. This framework is divided into two steps of the aeroelastic design initialization and aerodynamic Pareto front determination. First, the blade profiles are optimized to improve the aeroelastic stability only and constrain the variations of aerodynamic performances. Second, the optimized blade profiles in the first step are used as the initial ones and then further optimized with the objective function of aerodynamic parameters and the constraints of aeroelastic parameters. The effectiveness of the multi-objective design optimization method is demonstrated by comparing the optimization results with those from the single-objective aerodynamic and aeroelastic coupled design optimization method. The results from transonic NASA Rotor 67 subjected to a hypothetic vibration mode show that the multi-objective coupled design optimization method is capable of improving performances in both disciplines.
{"title":"Multi-objective aerodynamic and aeroelastic coupled design optimization using a full viscosity discrete adjoint harmonic balance method","authors":"Hangkong Wu, Dingxi Wang, Xiuquan Huang","doi":"10.1115/1.4062803","DOIUrl":"https://doi.org/10.1115/1.4062803","url":null,"abstract":"\u0000 With increasing requirements for high-loading and high-efficiency turbomachines, blades become thinner and thinner and thus design optimizations considering both aerodynamic performances and aeroelastic stability become more and more necessary. In this study, a full viscosity discrete adjoint harmonic balance (HB) solver has been developed using algorithmic differentiation (AD), verified by a discrete linear solver based upon duality property, and then adopted to perform multi-disciplinary coupled design optimizations. To this end, a framework of multi-objective adjoint design optimizations has been developed to improve both aerodynamic performances and aeroelastic stability of turbomachinery blades. This framework is divided into two steps of the aeroelastic design initialization and aerodynamic Pareto front determination. First, the blade profiles are optimized to improve the aeroelastic stability only and constrain the variations of aerodynamic performances. Second, the optimized blade profiles in the first step are used as the initial ones and then further optimized with the objective function of aerodynamic parameters and the constraints of aeroelastic parameters. The effectiveness of the multi-objective design optimization method is demonstrated by comparing the optimization results with those from the single-objective aerodynamic and aeroelastic coupled design optimization method. The results from transonic NASA Rotor 67 subjected to a hypothetic vibration mode show that the multi-objective coupled design optimization method is capable of improving performances in both disciplines.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49293532","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}
This paper investigated the film-cooling effectiveness of diffusion slot holes in a turbine nozzle guide vane. The pressure-sensitive paint measurement technique was employed to obtain the film-cooling effectiveness at a density ratio of DR = 1.5. The mainstream Reynolds number based on the axial chord length and the exit velocity was 60000. The mainstream turbulence intensity was approximately 3.7%. Three diffusion slot hole geometries with cross-sectional aspect ratios (ASs) of 2.3, 3.4, and 4.9 were tested and compared with a typical fan-shaped hole. The experiments were performed at three typical hole row locations on the pressure surface (PS) and suction surface (SS). The average blowing ratios varied from M = 0.5 to 2.5. The results showed that throughout the blowing ratio range, on the PS, a substantially higher film-cooling effectiveness than the fan-shaped hole is always obtained from the diffusion slot hole with a large AS (AS = 4.9); on the SS, the diffusion slot hole with a small AS (AS = 2.3). The influence of hole row positioning is inconsistent for diffusion slot holes with different ASs. The diffusion slot hole is less affected by the PS when the AS is moderate and less affected by the SS when the AS is large. The film-cooling effectiveness of the diffusion slot holes is basically the lowest where the PS has a maximum concave curvature and the highest where the SS has a large favorable pressure gradient.
{"title":"Film Cooling Effectiveness on Pressure Surface and Suction Surface of Turbine Guide Vane with Diffusion Slot Holes","authors":"Jia‐miao Hu, B. An","doi":"10.1115/1.4062805","DOIUrl":"https://doi.org/10.1115/1.4062805","url":null,"abstract":"\u0000 This paper investigated the film-cooling effectiveness of diffusion slot holes in a turbine nozzle guide vane. The pressure-sensitive paint measurement technique was employed to obtain the film-cooling effectiveness at a density ratio of DR = 1.5. The mainstream Reynolds number based on the axial chord length and the exit velocity was 60000. The mainstream turbulence intensity was approximately 3.7%. Three diffusion slot hole geometries with cross-sectional aspect ratios (ASs) of 2.3, 3.4, and 4.9 were tested and compared with a typical fan-shaped hole. The experiments were performed at three typical hole row locations on the pressure surface (PS) and suction surface (SS). The average blowing ratios varied from M = 0.5 to 2.5. The results showed that throughout the blowing ratio range, on the PS, a substantially higher film-cooling effectiveness than the fan-shaped hole is always obtained from the diffusion slot hole with a large AS (AS = 4.9); on the SS, the diffusion slot hole with a small AS (AS = 2.3). The influence of hole row positioning is inconsistent for diffusion slot holes with different ASs. The diffusion slot hole is less affected by the PS when the AS is moderate and less affected by the SS when the AS is large. The film-cooling effectiveness of the diffusion slot holes is basically the lowest where the PS has a maximum concave curvature and the highest where the SS has a large favorable pressure gradient.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41993688","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 Film cooling is used to protect turbine components from the extreme temperatures by ejecting coolant through arrays of holes to create an air buffer from the hot combustion gases. Limitations in traditional machining meant film cooling holes universally have sharp inlets, which create separation regions at the hole entrance. The present study uses experimental and computational data to show that these inlet separation are a major cause of performance variation in crossflow fed film cooling holes. Three-hole designs were experimentally tested by independently varying the coolant velocity ratio (VR) and the coolant channel velocity ratio (VRc) to isolate the effects of crossflow on hole performance. Leveraging additive manufacturing (AM) technologies, the addition of a 0.25D radius fillet to the inlet of a 7-7-7 shaped hole is shown to significantly improve diffuser usage and significantly reduce variation in performance with VRc. A second AM design used a very large radius of curvature inlet to reduce biasing caused by the inlet crossflow. Experiments showed that this “swept” hole design did minimize biasing of the coolant flow to one side of the shaped hole, and it significantly reduced variations due to varying VRc. RANS simulations at six VR and three VRc conditions were made for each geometry to better understand how the new geometries changed the velocity field within the hole. The sharp and rounded inlets were seen to have very similar tangential velocity fields and jet biasing. Both AM inlets created more uniform, slower velocity fields entering the diffuser. The results of this article indicate that large improvements in film cooling performance can be found by leveraging AM technology.
{"title":"Experimental and Computational Investigation of Shaped Film Cooling Holes Designed to Minimize Inlet Separation","authors":"Fraser Jones, Dale W Fox, David G. Bogard","doi":"10.1115/1.4062460","DOIUrl":"https://doi.org/10.1115/1.4062460","url":null,"abstract":"Abstract Film cooling is used to protect turbine components from the extreme temperatures by ejecting coolant through arrays of holes to create an air buffer from the hot combustion gases. Limitations in traditional machining meant film cooling holes universally have sharp inlets, which create separation regions at the hole entrance. The present study uses experimental and computational data to show that these inlet separation are a major cause of performance variation in crossflow fed film cooling holes. Three-hole designs were experimentally tested by independently varying the coolant velocity ratio (VR) and the coolant channel velocity ratio (VRc) to isolate the effects of crossflow on hole performance. Leveraging additive manufacturing (AM) technologies, the addition of a 0.25D radius fillet to the inlet of a 7-7-7 shaped hole is shown to significantly improve diffuser usage and significantly reduce variation in performance with VRc. A second AM design used a very large radius of curvature inlet to reduce biasing caused by the inlet crossflow. Experiments showed that this “swept” hole design did minimize biasing of the coolant flow to one side of the shaped hole, and it significantly reduced variations due to varying VRc. RANS simulations at six VR and three VRc conditions were made for each geometry to better understand how the new geometries changed the velocity field within the hole. The sharp and rounded inlets were seen to have very similar tangential velocity fields and jet biasing. Both AM inlets created more uniform, slower velocity fields entering the diffuser. The results of this article indicate that large improvements in film cooling performance can be found by leveraging AM technology.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135050892","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}
N. Maroldt, Stefanie Lohse, J. Seume, Matthias Kalla, B. Ponick
To date, design processes for electrically powered compressor are mainly based on separate processes for each individual component. Whereas the blading is often designed by an integrated aerodynamic and mechanical design optimization, additional components such as the electrical machine are usually not included. These approaches neglect the interactions of the individual components, which can influence the system performance. This paper demonstrates a multidisciplinary design approach, combining an optimization approach for a compressor stage and an electrical machine. The automated optimization process is based on an evolutionary algorithm, evaluating each individual of a population in terms of aerodynamic performance, structural integrity and performance of the electrical machine. This approach is applied to the design of a mixed-flow compressor for active high-lift applications in aircraft. The results suggest that the overall system efficiency is mainly influenced by the compressor stage, whereas the system mass is dominated by the electrical components which highlights the need to combine both optimization approaches. Key design parameters of high power-density electrical-machine designs are identified. A comparison between a previous compressor-only optimization and a new design based on the new multidisciplinary optimization confirms the improvements the latter optimization approach yields.
{"title":"Multidisciplinary Design of an Electrically Powered High-Lift System","authors":"N. Maroldt, Stefanie Lohse, J. Seume, Matthias Kalla, B. Ponick","doi":"10.1115/1.4062677","DOIUrl":"https://doi.org/10.1115/1.4062677","url":null,"abstract":"\u0000 To date, design processes for electrically powered compressor are mainly based on separate processes for each individual component. Whereas the blading is often designed by an integrated aerodynamic and mechanical design optimization, additional components such as the electrical machine are usually not included. These approaches neglect the interactions of the individual components, which can influence the system performance. This paper demonstrates a multidisciplinary design approach, combining an optimization approach for a compressor stage and an electrical machine. The automated optimization process is based on an evolutionary algorithm, evaluating each individual of a population in terms of aerodynamic performance, structural integrity and performance of the electrical machine. This approach is applied to the design of a mixed-flow compressor for active high-lift applications in aircraft. The results suggest that the overall system efficiency is mainly influenced by the compressor stage, whereas the system mass is dominated by the electrical components which highlights the need to combine both optimization approaches. Key design parameters of high power-density electrical-machine designs are identified. A comparison between a previous compressor-only optimization and a new design based on the new multidisciplinary optimization confirms the improvements the latter optimization approach yields.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46214665","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}
Additive manufacturing (AM), particularly laser powder bed fusion, is growing the ability to rapidly develop advanced cooling schemes for turbomachinery applications. However, to fully utilize the design and development opportunities offered through AM, impacts of the build considerations and processing parameters are needed. Prior literature has shown that specific build considerations such as laser incidence angle and wall thickness influence the surface roughness of additively made components. The objective of this technical brief is to highlight the effects of both laser incidence angle and wall thickness on the surface roughness and cooling performance in micro-sized cooling passages. Results indicate that for any given laser incidence angle, surface roughness begins to increase when wall thickness is less than 1 mm for the cooling channels evaluated. As the laser incidence angle becomes further away from 90° the surface roughness increases in a parabolic form. Laser incidence angle and wall thickness significantly impacts friction factor, while there is less of an influence on Nusselt number for additively manufactured microchannels.
{"title":"INFLUENCES OF LASER INCIDENCE ANGLE AND WALL THICKNESS ON ADDITIVE COMPONENTS","authors":"Alexander Wildgoose, K. Thole","doi":"10.1115/1.4062678","DOIUrl":"https://doi.org/10.1115/1.4062678","url":null,"abstract":"\u0000 Additive manufacturing (AM), particularly laser powder bed fusion, is growing the ability to rapidly develop advanced cooling schemes for turbomachinery applications. However, to fully utilize the design and development opportunities offered through AM, impacts of the build considerations and processing parameters are needed. Prior literature has shown that specific build considerations such as laser incidence angle and wall thickness influence the surface roughness of additively made components. The objective of this technical brief is to highlight the effects of both laser incidence angle and wall thickness on the surface roughness and cooling performance in micro-sized cooling passages. Results indicate that for any given laser incidence angle, surface roughness begins to increase when wall thickness is less than 1 mm for the cooling channels evaluated. As the laser incidence angle becomes further away from 90° the surface roughness increases in a parabolic form. Laser incidence angle and wall thickness significantly impacts friction factor, while there is less of an influence on Nusselt number for additively manufactured microchannels.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45543825","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 Modern civil jet engines arrange components on spools with different rotational speeds in order to improve compressor stall margin, overall engine performance, etc. The unsteady interactions among these components can be significant and should be considered at an early design stage if possible. Unsteady Reynolds-averaged Navier–Stokes (URANS) is a common approach to simulate these unsteady effects, but the disparity in time scales in a multispool simulation can lead to expensive URANS simulations. Harmonic methods are effective and efficient approaches to simulate unsteady interactions among turbomachinery components, but their applications to multispool simulations remain a challenge. The objective of this paper is to address this challenge. This paper extends the Favre-averaged non-linear harmonic method to simulate multispool turbomachinery components using a unified bladerow interface which transfers disturbances through bladerows with arbitrary blade counts at any rotational speed. The regularization of non-reflective boundary condition is described for certain circumferential wave number of the zero-frequency mode. The capability of the proposed approach is demonstrated by simulating the transfer of hot streaks through full 3D high- and intermediate-pressure turbines in a three-shaft engine. The temperature distributions from the harmonic method show good agreement with direct unsteady simulation in terms of the mean flow and the instantaneous flow. The radial migration of the hot streaks towards the hub are captured very well by the proposed harmonic method. The required wall-clock time of the harmonic method is roughly 240 times smaller than the whole annulus URANS simulation. This demonstrates that the proposed method can be an efficient design tool to trace hot streaks in multispool turbines at the early design stage.
{"title":"Harmonic Method for Simulating Unsteady Multispool Interactions","authors":"Feng Wang, Luca di Mare","doi":"10.1115/1.4062242","DOIUrl":"https://doi.org/10.1115/1.4062242","url":null,"abstract":"Abstract Modern civil jet engines arrange components on spools with different rotational speeds in order to improve compressor stall margin, overall engine performance, etc. The unsteady interactions among these components can be significant and should be considered at an early design stage if possible. Unsteady Reynolds-averaged Navier–Stokes (URANS) is a common approach to simulate these unsteady effects, but the disparity in time scales in a multispool simulation can lead to expensive URANS simulations. Harmonic methods are effective and efficient approaches to simulate unsteady interactions among turbomachinery components, but their applications to multispool simulations remain a challenge. The objective of this paper is to address this challenge. This paper extends the Favre-averaged non-linear harmonic method to simulate multispool turbomachinery components using a unified bladerow interface which transfers disturbances through bladerows with arbitrary blade counts at any rotational speed. The regularization of non-reflective boundary condition is described for certain circumferential wave number of the zero-frequency mode. The capability of the proposed approach is demonstrated by simulating the transfer of hot streaks through full 3D high- and intermediate-pressure turbines in a three-shaft engine. The temperature distributions from the harmonic method show good agreement with direct unsteady simulation in terms of the mean flow and the instantaneous flow. The radial migration of the hot streaks towards the hub are captured very well by the proposed harmonic method. The required wall-clock time of the harmonic method is roughly 240 times smaller than the whole annulus URANS simulation. This demonstrates that the proposed method can be an efficient design tool to trace hot streaks in multispool turbines at the early design stage.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135478557","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}
Wenwu Zhou, Hongyi Shao, Xu Zhang, D. Peng, Yingzheng Liu, Yang Li, Weihua Yang, Xiaofeng Zhao
Practical strategy for the thermal evaluation of film-cooled blade is of great importance to the gas turbine community. Due to the physical or methodology limitations, it is difficult to evaluate the blade's thermal performance at simulated engine conditions. The present study proposed novel focal-sweep-based phosphor thermometry for blade cooling inspection. While Mg4FGeO6:Mn (MFG) served as the temperature sensor to quantify the blade temperatures as well as simulated the TBC effect, the focal sweep method was adopted to overcome the optical constraints in cascade testing. The obtained MFG results of microstructures, jet impingement, and anti-erosion test demonstrated that the MFG phosphor is robust enough to simulate the thermal insulation effect of TBC and can withstand high-speed flow erosion. Furthermore, the proposed strategy clearly captured the blade temperature distributions (mainstream at T_(0,8)=~850 K) with high spatial resolution, which was then successfully remapped onto the three-dimensional twisted blade. Additional comparisons with the thermocouples demonstrated that the simulated-TBC has a thermal insulation effect of about 68K. This study addressed the common problems of phosphor thermometry in blade cooling evaluation, offering a practical strategy for future thermal diagnostics of the gas turbine.
{"title":"Novel strategy for thermal evaluation of film-cooled blades using thermographic phosphors at simulated engine conditions","authors":"Wenwu Zhou, Hongyi Shao, Xu Zhang, D. Peng, Yingzheng Liu, Yang Li, Weihua Yang, Xiaofeng Zhao","doi":"10.1115/1.4062611","DOIUrl":"https://doi.org/10.1115/1.4062611","url":null,"abstract":"\u0000 Practical strategy for the thermal evaluation of film-cooled blade is of great importance to the gas turbine community. Due to the physical or methodology limitations, it is difficult to evaluate the blade's thermal performance at simulated engine conditions. The present study proposed novel focal-sweep-based phosphor thermometry for blade cooling inspection. While Mg4FGeO6:Mn (MFG) served as the temperature sensor to quantify the blade temperatures as well as simulated the TBC effect, the focal sweep method was adopted to overcome the optical constraints in cascade testing. The obtained MFG results of microstructures, jet impingement, and anti-erosion test demonstrated that the MFG phosphor is robust enough to simulate the thermal insulation effect of TBC and can withstand high-speed flow erosion. Furthermore, the proposed strategy clearly captured the blade temperature distributions (mainstream at T_(0,8)=~850 K) with high spatial resolution, which was then successfully remapped onto the three-dimensional twisted blade. Additional comparisons with the thermocouples demonstrated that the simulated-TBC has a thermal insulation effect of about 68K. This study addressed the common problems of phosphor thermometry in blade cooling evaluation, offering a practical strategy for future thermal diagnostics of the gas turbine.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45506030","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}
Despite the extensive application of three-dimensional Reynolds-averaged Navier-Stokes equation (RANS) in axial compressor numerical simulations, body-force model (BFM) also plays its own role profiting from its low computation cost. However, the computation accuracy highly depends on the modeling of blade force, which usually involves several parameter constants. In this work, data assimilation based on Ensemble Kalman Filter (EnKF) was employed to optimize these model constants in BFM. Previous work associated with data assimilation mainly focus on employing only one data source. Considering the various measurement quantities in engineering practice, disparate data were incorporated in assimilation method to improve the prediction. The test case of a low-speed axial compressor was provided. Only one single data source, i.e., total pressure ratio, was first employed as the observation data in EnKF. And to reveal the superiority of the disparate data assimilation, total pressure ratio and isentropic efficiency were then incorporated to improve the performance prediction. The converged results reveal the robustness of disparate data assimilation based on EnKF. At last, the optimized constants were adopted to predict the performance of the axial compressor at another rotational speed for further verification and application. The results showed that errors comparing with the experimental data are nearly within 2.5%.
{"title":"Assimilation of Disparate Data for Improving the Performance Prediction of Body-Force Model","authors":"Xuegao Wang, Jun Hu, Shuai Ma","doi":"10.1115/1.4062610","DOIUrl":"https://doi.org/10.1115/1.4062610","url":null,"abstract":"\u0000 Despite the extensive application of three-dimensional Reynolds-averaged Navier-Stokes equation (RANS) in axial compressor numerical simulations, body-force model (BFM) also plays its own role profiting from its low computation cost. However, the computation accuracy highly depends on the modeling of blade force, which usually involves several parameter constants. In this work, data assimilation based on Ensemble Kalman Filter (EnKF) was employed to optimize these model constants in BFM. Previous work associated with data assimilation mainly focus on employing only one data source. Considering the various measurement quantities in engineering practice, disparate data were incorporated in assimilation method to improve the prediction. The test case of a low-speed axial compressor was provided. Only one single data source, i.e., total pressure ratio, was first employed as the observation data in EnKF. And to reveal the superiority of the disparate data assimilation, total pressure ratio and isentropic efficiency were then incorporated to improve the performance prediction. The converged results reveal the robustness of disparate data assimilation based on EnKF. At last, the optimized constants were adopted to predict the performance of the axial compressor at another rotational speed for further verification and application. The results showed that errors comparing with the experimental data are nearly within 2.5%.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2023-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44437250","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 In the last decade, progresses in additive manufacturing (AM) have paved the way for optimized heat exchangers whose disruptive design will heavily rely on predictive numerical simulations. However, due to typical roughness induced by AM, current wall models used in steady and unsteady 3D Navier–Stokes simulations do not take into account such characteristics. For the development and assessment of novel wall models for AM, a high-fidelity roughness-resolved large-eddy simulation (RRLES) database is built. This article describes the numerical setup and the methodology used for conducting RRLES, from surface generation to postprocessing. In addition, three different cases representing two printing directions plus a streamwise and spanwise isotropic case are investigated. While the roughness distributions are the same in the three cases, the effective slope (ES) is very different, and the impact of this parameter on turbulence and heat transfer is analyzed at different Reynolds numbers.
{"title":"Roughness-Resolved Large-Eddy Simulation of Additive Manufacturing-Like Channel Flows","authors":"Serge Meynet, Alexis Barge, Vincent Moureau, Guillaume Balarac, Ghislain Lartigue, Abdellah Hadjadj","doi":"10.1115/1.4062245","DOIUrl":"https://doi.org/10.1115/1.4062245","url":null,"abstract":"Abstract In the last decade, progresses in additive manufacturing (AM) have paved the way for optimized heat exchangers whose disruptive design will heavily rely on predictive numerical simulations. However, due to typical roughness induced by AM, current wall models used in steady and unsteady 3D Navier–Stokes simulations do not take into account such characteristics. For the development and assessment of novel wall models for AM, a high-fidelity roughness-resolved large-eddy simulation (RRLES) database is built. This article describes the numerical setup and the methodology used for conducting RRLES, from surface generation to postprocessing. In addition, three different cases representing two printing directions plus a streamwise and spanwise isotropic case are investigated. While the roughness distributions are the same in the three cases, the effective slope (ES) is very different, and the impact of this parameter on turbulence and heat transfer is analyzed at different Reynolds numbers.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135335626","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 This article presents an integral validation of a synthetic turbulence broadband noise prediction methodology for fan/outlet-guide-vane (OGV) interaction. The test vehicle is the ACAT1 fan, a modern scaled-down fan, experimentally analyzed in 2018 within the TurboNoiseBB project. Three operating points, namely, Approach, Cutback, and Sideline, and two different rig configurations in terms of the axial gap between the fan and OGV are examined within this work. The methodology consists of using a Reynolds-averaged Navier–Stokes (RANS) solver to model the fan wake and the use of two-dimensional frequency domain linearized Navier–Stokes simulations to resolve the acoustics, including quasi-3D corrections to obtain representative results. The RANS results with no ad hoc tuning are compared in detail against hotwire data to determine the degree of uncertainty incurred by this kind of approach. The predicted broadband noise spectra and noise azimuthal decompositions are compared against the experimental data. The spectral levels are well predicted despite an average underprediction of around 3dB. The noise azimuthal decompositions feature a remarkable agreement with the experiment, denoting accurate modeling of the main physics governing the problem. The impact of increasing the fan/OGV axial gap is quantified numerically for the first time. It is concluded that increasing the gap is detrimental for the broadband noise footprint, unlike intuitively could be expected. Overall, the presented broadband noise methodology yields robust broadband noise predictions at an industrially feasible cost and enables a deeper understanding of the problem.
{"title":"Validation of Broadband Noise Prediction Methodology Based on Linearized Navier–Stokes Analyses","authors":"Ricardo Blázquez-Navarro, Roque Corral","doi":"10.1115/1.4062398","DOIUrl":"https://doi.org/10.1115/1.4062398","url":null,"abstract":"Abstract This article presents an integral validation of a synthetic turbulence broadband noise prediction methodology for fan/outlet-guide-vane (OGV) interaction. The test vehicle is the ACAT1 fan, a modern scaled-down fan, experimentally analyzed in 2018 within the TurboNoiseBB project. Three operating points, namely, Approach, Cutback, and Sideline, and two different rig configurations in terms of the axial gap between the fan and OGV are examined within this work. The methodology consists of using a Reynolds-averaged Navier–Stokes (RANS) solver to model the fan wake and the use of two-dimensional frequency domain linearized Navier–Stokes simulations to resolve the acoustics, including quasi-3D corrections to obtain representative results. The RANS results with no ad hoc tuning are compared in detail against hotwire data to determine the degree of uncertainty incurred by this kind of approach. The predicted broadband noise spectra and noise azimuthal decompositions are compared against the experimental data. The spectral levels are well predicted despite an average underprediction of around 3dB. The noise azimuthal decompositions feature a remarkable agreement with the experiment, denoting accurate modeling of the main physics governing the problem. The impact of increasing the fan/OGV axial gap is quantified numerically for the first time. It is concluded that increasing the gap is detrimental for the broadband noise footprint, unlike intuitively could be expected. Overall, the presented broadband noise methodology yields robust broadband noise predictions at an industrially feasible cost and enables a deeper understanding of the problem.","PeriodicalId":49966,"journal":{"name":"Journal of Turbomachinery-Transactions of the Asme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135287984","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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