The preliminary design of an aero-engine combustor is a multidisciplinary process that involves an extensive and systematic analysis of the design space. Simulation-driven approaches, in which several design configurations are numerically analyzed, may lead to heterogeneous models interacting with each other, sharing miscellaneous information within the process. Iterative and user-defined approaches, moreover, are inefficient when multiple and conflicting requirements are in place. To rely on integrated design methodologies has been demonstrated to be beneficial, especially if adopted in a structured approach to design optimization. In this paper, the application of the Combustor Design System Integration (DSI) to the definition of an optimal combustor preliminary configuration will be presented. Given a combustor baseline design, the multi-objective optimization problem has been defined by targeting an optimal distribution for temperature profiles and patterns at the combustor’s exit. Dilution port characteristics, such as hole number and dimension as well as the axial position of the row have been selected as design variables. To guarantee a water-tight design process while minimizing the user effort, the DSI tools were included in a dedicated framework for driving the optimization tasks. Here, a proper CFD domain for RANS, constituted by the flame tube region extended to the dilution port feeds, was adopted for imposing the air split designed for the combustor. Concerning a “complete” combustor sector, this allows a reduction in the computational effort while still being representative for its aero-thermal behavior. The optimization task was performed using a Response Surface Method (RSM), in which multiple, specific combustor configurations were simulated and the CFD result elaborated to build a meta-model of the combustor itself. Finally, the suitability of the resulting optimized configuration has been evaluated through an “a posteriori” analysis for thermal conditions and emission levels (NOx and CO). A lean combustion concept developed by Avio Aero with the aim of the homonymous EU research project, the NEWAC combustor, has been considered as test case.
{"title":"Multi-Objective Optimization of Aero Engine Combustor Adopting an Integrated Procedure for Aero-Thermal Preliminary Design","authors":"C. Elmi, I. Vitale, H. Reese, A. Andreini","doi":"10.1115/gt2021-58945","DOIUrl":"https://doi.org/10.1115/gt2021-58945","url":null,"abstract":"\u0000 The preliminary design of an aero-engine combustor is a multidisciplinary process that involves an extensive and systematic analysis of the design space. Simulation-driven approaches, in which several design configurations are numerically analyzed, may lead to heterogeneous models interacting with each other, sharing miscellaneous information within the process. Iterative and user-defined approaches, moreover, are inefficient when multiple and conflicting requirements are in place. To rely on integrated design methodologies has been demonstrated to be beneficial, especially if adopted in a structured approach to design optimization.\u0000 In this paper, the application of the Combustor Design System Integration (DSI) to the definition of an optimal combustor preliminary configuration will be presented. Given a combustor baseline design, the multi-objective optimization problem has been defined by targeting an optimal distribution for temperature profiles and patterns at the combustor’s exit. Dilution port characteristics, such as hole number and dimension as well as the axial position of the row have been selected as design variables. To guarantee a water-tight design process while minimizing the user effort, the DSI tools were included in a dedicated framework for driving the optimization tasks. Here, a proper CFD domain for RANS, constituted by the flame tube region extended to the dilution port feeds, was adopted for imposing the air split designed for the combustor. Concerning a “complete” combustor sector, this allows a reduction in the computational effort while still being representative for its aero-thermal behavior. The optimization task was performed using a Response Surface Method (RSM), in which multiple, specific combustor configurations were simulated and the CFD result elaborated to build a meta-model of the combustor itself. Finally, the suitability of the resulting optimized configuration has been evaluated through an “a posteriori” analysis for thermal conditions and emission levels (NOx and CO).\u0000 A lean combustion concept developed by Avio Aero with the aim of the homonymous EU research project, the NEWAC combustor, has been considered as test case.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"382 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123346728","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}
With an increasing instability and cost fluctuation in the world energy markets, it has become more important to increase the US Navy fleet’s overall fuel efficiency. The Navy’s Energy Program for Security and Independence sets forth goals to reduce its overall consumption of energy and decrease its reliance on petroleum. One way that helps accomplish these goals is through the use of hybrid electric drive systems to replace gas turbine engines to accomplish lower ship speeds. Although gas turbines are power dense and fairly efficient at full load, their fuel efficiency decreases drastically at the lower power levels used when slower speeds are required to accomplish the ship’s mission. It is in this lower speed range where operating gas turbine generators closer to their optimum efficiency levels and powering an electric motor saves a significant amount of fuel. This paper will discuss two in-service systems developed for various US Navy ships: the Hybrid Electric Drive (HED) system for DDG 103 and the Auxiliary Propulsion System (APS) for LHD 8 and LHA 7. It will describe each of the two configurations and their histories, how they are implemented and increase the capability of the ship, and the resulting fuel efficiencies that have been realized with their use.
{"title":"Hybrid Electric Drive Systems in the United States Navy","authors":"Gianfranco P. Buonamici","doi":"10.1115/gt2021-03523","DOIUrl":"https://doi.org/10.1115/gt2021-03523","url":null,"abstract":"\u0000 With an increasing instability and cost fluctuation in the world energy markets, it has become more important to increase the US Navy fleet’s overall fuel efficiency. The Navy’s Energy Program for Security and Independence sets forth goals to reduce its overall consumption of energy and decrease its reliance on petroleum. One way that helps accomplish these goals is through the use of hybrid electric drive systems to replace gas turbine engines to accomplish lower ship speeds. Although gas turbines are power dense and fairly efficient at full load, their fuel efficiency decreases drastically at the lower power levels used when slower speeds are required to accomplish the ship’s mission. It is in this lower speed range where operating gas turbine generators closer to their optimum efficiency levels and powering an electric motor saves a significant amount of fuel.\u0000 This paper will discuss two in-service systems developed for various US Navy ships: the Hybrid Electric Drive (HED) system for DDG 103 and the Auxiliary Propulsion System (APS) for LHD 8 and LHA 7. It will describe each of the two configurations and their histories, how they are implemented and increase the capability of the ship, and the resulting fuel efficiencies that have been realized with their use.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116390761","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}
As a renewable, unlimited and free resource, wind energy has been intensively deployed in the past to generate electricity. However, the maintenance of Wind Turbines (WTs) can be challengeable. On the one hand, most wind farms operate in remote areas and on the other hand, the dimension of WTs’ tip/hub/rotor are usually enormous. In order to prevent abrupt breakdowns of WTs, a number of Condition Monitoring (CM) methods have been proposed. Focusing on bearing diagnostics, Squared Envelope Spectrum is one of the most common techniques. Moreover in order to identify the optimum demodulation frequency band, fast Kurtogram, Infogram and Sparsogram are nowadays popular tools evaluating respectively the Kurtosis, the Negentropy and the Sparsity. The analysis of WTs usually requires high effort due to the complexity of the drivetrain and the varying operating conditions and therefore there is still need for research on effective and reliable CM techniques for WT monitoring. Thus the purpose of this paper is to investigate a blind and effective CM approach based on the Scattering Transform. Through the comparison with state of the art techniques, the proposed methodology is found more powerful to detect a fault on six validated WT datasets.
{"title":"Condition Monitoring of Wind Turbines Based on the Scattering Transform of Vibration Data","authors":"Junyu Qi, Alexandre Mauricio, K. Gryllias","doi":"10.1115/gt2021-60280","DOIUrl":"https://doi.org/10.1115/gt2021-60280","url":null,"abstract":"\u0000 As a renewable, unlimited and free resource, wind energy has been intensively deployed in the past to generate electricity. However, the maintenance of Wind Turbines (WTs) can be challengeable. On the one hand, most wind farms operate in remote areas and on the other hand, the dimension of WTs’ tip/hub/rotor are usually enormous. In order to prevent abrupt breakdowns of WTs, a number of Condition Monitoring (CM) methods have been proposed. Focusing on bearing diagnostics, Squared Envelope Spectrum is one of the most common techniques. Moreover in order to identify the optimum demodulation frequency band, fast Kurtogram, Infogram and Sparsogram are nowadays popular tools evaluating respectively the Kurtosis, the Negentropy and the Sparsity. The analysis of WTs usually requires high effort due to the complexity of the drivetrain and the varying operating conditions and therefore there is still need for research on effective and reliable CM techniques for WT monitoring. Thus the purpose of this paper is to investigate a blind and effective CM approach based on the Scattering Transform. Through the comparison with state of the art techniques, the proposed methodology is found more powerful to detect a fault on six validated WT datasets.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133874184","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}
Effects of yawed incoming flow on wind turbine blades forces and root bending moments (RBMs) are not fully understood. To advance our current understanding, numerical studies of a small-scale three-bladed horizontal axis wind turbine at TSR = 6.7 with yaw angles of zero and 45° have been carried out to examine the variations of blade and rotor loading due to the yawed incoming flow. An approach combining Large Eddy Simulation (LES) with Actuator Line Modelling (ALM) has been employed in the present study. The predicted phase-averaged blade forces reveal that the blade tangential force, in-plane RBM and power coefficient are much more sensitive to the upstream streamwise velocity variations and are much more strongly affected than the blade axial force, out-of-plane RBM and thrust coefficient. It also shows that for yawed incoming flows the blade axial force to the blade tangential force ratio fluctuates significantly during one rotor revolution, resulting in large variations of the blade elastic torsion and that the total blade force (magnitude and direction) undergoes a non-linear change in the circumferential and radial directions, which will likely lead to the reduction in the turbine operational life significantly, especially for long lightweight blades of large size wind turbines.
{"title":"Influence of Yawed Wind Flow on the Blade Forces/Bending Moments and Blade Elastic Torsion for an Axial-Flow Wind Turbine","authors":"M. Ahmadi, Zhiyin Yang","doi":"10.1115/gt2021-60237","DOIUrl":"https://doi.org/10.1115/gt2021-60237","url":null,"abstract":"\u0000 Effects of yawed incoming flow on wind turbine blades forces and root bending moments (RBMs) are not fully understood. To advance our current understanding, numerical studies of a small-scale three-bladed horizontal axis wind turbine at TSR = 6.7 with yaw angles of zero and 45° have been carried out to examine the variations of blade and rotor loading due to the yawed incoming flow. An approach combining Large Eddy Simulation (LES) with Actuator Line Modelling (ALM) has been employed in the present study. The predicted phase-averaged blade forces reveal that the blade tangential force, in-plane RBM and power coefficient are much more sensitive to the upstream streamwise velocity variations and are much more strongly affected than the blade axial force, out-of-plane RBM and thrust coefficient. It also shows that for yawed incoming flows the blade axial force to the blade tangential force ratio fluctuates significantly during one rotor revolution, resulting in large variations of the blade elastic torsion and that the total blade force (magnitude and direction) undergoes a non-linear change in the circumferential and radial directions, which will likely lead to the reduction in the turbine operational life significantly, especially for long lightweight blades of large size wind turbines.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115231629","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}
J. Patterson, Kevin D. Fauvell, Dennis M. Russom, Willie A. Durosseau, Phyllis Petronello, J. Moralez
The United States Navy (USN) 501-K Series Radiological Controls (RADCON) Program was launched in late 2011, in response to the extensive damage caused by participation in Operation Tomodachi. The purpose of this operation was to provide humanitarian relief aid to Japan following a 9.0 magnitude earthquake that struck 231 miles northeast of Tokyo, on the afternoon of March 11, 2011. The earthquake caused a tsunami with 30 foot waves that damaged several nuclear reactors in the area. It was the fourth largest earthquake on record (since 1900) and the largest to hit Japan. On March 12, 2011, the United States Government launched Operation Tomodachi. In all, a total of 24,000 troops, 189 aircraft, 24 naval ships, supported this relief effort, at a cost in excess of $90.0 million. The U.S. Navy provided material support, personnel movement, search and rescue missions and damage surveys. During the operation, 11 gas turbine powered U.S. warships operated within the radioactive plume. As a result, numerous gas turbine engines ingested radiological contaminants and needed to be decontaminated, cleaned, repaired and returned to the Fleet. During the past eight years, the USN has been very proactive and vigilant with their RADCON efforts, and as of the end of calendar year 2019, have successfully completed the 501-K Series portion of the RADCON program. This paper will update an earlier ASME paper that was written on this subject (GT2015-42057) and will summarize the U.S. Navy’s 501-K Series RADCON effort. Included in this discussion will be a summary of the background of Operation Tomodachi, including a discussion of the affected hulls and related gas turbine equipment. In addition, a discussion of the radiological contamination caused by the disaster will be covered and the resultant effect to and the response by the Marine Gas Turbine Program. Furthermore, the authors will discuss what the USN did to remediate the RADCON situation, what means were employed to select a vendor and to set up a RADCON cleaning facility in the United States. And finally, the authors will discuss the dispensation of the 501-K Series RADCON assets that were not returned to service, which include the 501-K17 gas turbine engine, as well as the 250-KS4 gas turbine engine starter. The paper will conclude with a discussion of the results and lessons learned of the program and discuss how the USN was able to process all of their 501-K34 RADCON affected gas turbine engines and return them back to the Fleet in a timely manner.
{"title":"Case Closed: The Completion of the United States Navy 501-K34 Gas Turbine Engine RADCON Program (2011 - 2019)","authors":"J. Patterson, Kevin D. Fauvell, Dennis M. Russom, Willie A. Durosseau, Phyllis Petronello, J. Moralez","doi":"10.1115/gt2021-00379","DOIUrl":"https://doi.org/10.1115/gt2021-00379","url":null,"abstract":"\u0000 The United States Navy (USN) 501-K Series Radiological Controls (RADCON) Program was launched in late 2011, in response to the extensive damage caused by participation in Operation Tomodachi. The purpose of this operation was to provide humanitarian relief aid to Japan following a 9.0 magnitude earthquake that struck 231 miles northeast of Tokyo, on the afternoon of March 11, 2011. The earthquake caused a tsunami with 30 foot waves that damaged several nuclear reactors in the area. It was the fourth largest earthquake on record (since 1900) and the largest to hit Japan. On March 12, 2011, the United States Government launched Operation Tomodachi. In all, a total of 24,000 troops, 189 aircraft, 24 naval ships, supported this relief effort, at a cost in excess of $90.0 million. The U.S. Navy provided material support, personnel movement, search and rescue missions and damage surveys. During the operation, 11 gas turbine powered U.S. warships operated within the radioactive plume. As a result, numerous gas turbine engines ingested radiological contaminants and needed to be decontaminated, cleaned, repaired and returned to the Fleet. During the past eight years, the USN has been very proactive and vigilant with their RADCON efforts, and as of the end of calendar year 2019, have successfully completed the 501-K Series portion of the RADCON program. This paper will update an earlier ASME paper that was written on this subject (GT2015-42057) and will summarize the U.S. Navy’s 501-K Series RADCON effort. Included in this discussion will be a summary of the background of Operation Tomodachi, including a discussion of the affected hulls and related gas turbine equipment. In addition, a discussion of the radiological contamination caused by the disaster will be covered and the resultant effect to and the response by the Marine Gas Turbine Program. Furthermore, the authors will discuss what the USN did to remediate the RADCON situation, what means were employed to select a vendor and to set up a RADCON cleaning facility in the United States. And finally, the authors will discuss the dispensation of the 501-K Series RADCON assets that were not returned to service, which include the 501-K17 gas turbine engine, as well as the 250-KS4 gas turbine engine starter. The paper will conclude with a discussion of the results and lessons learned of the program and discuss how the USN was able to process all of their 501-K34 RADCON affected gas turbine engines and return them back to the Fleet in a timely manner.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131152936","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}
J. Salomon, J. Göing, S. Lück, M. Broggi, J. Friedrichs, M. Beer
In this work the impact of combined module variances on the overall performance of a high-bypass aircraft engine is investigated. Therefore, a comprehensive sensitivity analysis on the example of a turbofan engine performance model is provided by means of Kucherenko indices. Direct influences of selected model inputs on key model outputs as well as influences due to interaction effects between these input variables are identified. The selected input variables of the performance model are partly subject to considerable dependencies that are taken into account by the Kucherenko indices. The results confirm known direct influences of deterioration effects on the key performance parameters of the aircraft engine on the one hand, and provide profound insights into complex interaction effects between the components and their impact on the V2500-A1 aircraft engine performance on the other.
{"title":"Sensitivity Analysis of an Aircraft Engine Model Under Consideration of Dependent Variables","authors":"J. Salomon, J. Göing, S. Lück, M. Broggi, J. Friedrichs, M. Beer","doi":"10.1115/gt2021-58905","DOIUrl":"https://doi.org/10.1115/gt2021-58905","url":null,"abstract":"\u0000 In this work the impact of combined module variances on the overall performance of a high-bypass aircraft engine is investigated. Therefore, a comprehensive sensitivity analysis on the example of a turbofan engine performance model is provided by means of Kucherenko indices. Direct influences of selected model inputs on key model outputs as well as influences due to interaction effects between these input variables are identified. The selected input variables of the performance model are partly subject to considerable dependencies that are taken into account by the Kucherenko indices.\u0000 The results confirm known direct influences of deterioration effects on the key performance parameters of the aircraft engine on the one hand, and provide profound insights into complex interaction effects between the components and their impact on the V2500-A1 aircraft engine performance on the other.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"180 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126746413","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}
A. Castorrini, P. Venturini, Fabrizio Gerboni, A. Corsini, F. Rispoli
Rain erosion of wind turbine blades represents an interesting topic of study due to its non-negligible impact on annual energy production of the wind farms installed in rainy sites. A considerable amount of recent research works has been oriented to this subject, proposing rain erosion modelling, performance losses prediction, structural issues studies, etc. This work aims to present a new method to predict the damage on a wind turbine blade. The method is applied here to study the effect of different rain conditions and blade coating materials, on the damage produced by the rain over a representative section of a reference 5MW turbine blade operating in normal turbulence wind conditions.
{"title":"Machine Learning Aided Prediction of Rain Erosion Damage on Wind Turbine Blade Sections","authors":"A. Castorrini, P. Venturini, Fabrizio Gerboni, A. Corsini, F. Rispoli","doi":"10.1115/gt2021-59156","DOIUrl":"https://doi.org/10.1115/gt2021-59156","url":null,"abstract":"\u0000 Rain erosion of wind turbine blades represents an interesting topic of study due to its non-negligible impact on annual energy production of the wind farms installed in rainy sites. A considerable amount of recent research works has been oriented to this subject, proposing rain erosion modelling, performance losses prediction, structural issues studies, etc. This work aims to present a new method to predict the damage on a wind turbine blade. The method is applied here to study the effect of different rain conditions and blade coating materials, on the damage produced by the rain over a representative section of a reference 5MW turbine blade operating in normal turbulence wind conditions.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"220 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122853042","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}
Commonly encountered thermal management challenges of today’s rapidly changing power density, raised-floor hot/cold aisle data centers include typically uncontrollable tile flow non-uniformity along the above-floor cold aisle. For example, the operational cooling provision intensity near the Computer Room Airflow Conditioner (CRAC) unit can be far less than that on the other side (far away from the CRAC unit). This undesired trend leads to an unbalanced aisle-level air cooling and subsequent inefficient power consumption. In this study, the CRAC turbofan blower flow boundary conditions were thoroughly investigated. Computational Fluid Dynamics (CFD) based simulations were employed to describe and evaluate the differently configured CRAC turbofan blower flow conditions (i.e., normal, angled, and sheared CRAC flow patterns) as well as their impacts upon the air cooling performance. This work indicates that the considered turbofan blower boundary condition, together with their underlying transportation mechanism within the plenum, might contribute an essential influence to the flow structure adjacent to the tile perforations. In particular, it was found that the sheared CRAC turbofan blower airflow pattern is capable of giving rise to favorable tile flow straightening manners. This finding further promotes an improvement of the consequently obtained aisle-level air cooling effectiveness and efficiencies, contributing to more advanced data center thermal management in the future.
{"title":"Study of CFD-Based Raised-Floor Data Center Cooling With Parametric CRAC Turbofan Blower Airflow Patterns","authors":"Zhihang Song, Wan Chen","doi":"10.1115/gt2021-58728","DOIUrl":"https://doi.org/10.1115/gt2021-58728","url":null,"abstract":"\u0000 Commonly encountered thermal management challenges of today’s rapidly changing power density, raised-floor hot/cold aisle data centers include typically uncontrollable tile flow non-uniformity along the above-floor cold aisle. For example, the operational cooling provision intensity near the Computer Room Airflow Conditioner (CRAC) unit can be far less than that on the other side (far away from the CRAC unit). This undesired trend leads to an unbalanced aisle-level air cooling and subsequent inefficient power consumption. In this study, the CRAC turbofan blower flow boundary conditions were thoroughly investigated. Computational Fluid Dynamics (CFD) based simulations were employed to describe and evaluate the differently configured CRAC turbofan blower flow conditions (i.e., normal, angled, and sheared CRAC flow patterns) as well as their impacts upon the air cooling performance. This work indicates that the considered turbofan blower boundary condition, together with their underlying transportation mechanism within the plenum, might contribute an essential influence to the flow structure adjacent to the tile perforations. In particular, it was found that the sheared CRAC turbofan blower airflow pattern is capable of giving rise to favorable tile flow straightening manners. This finding further promotes an improvement of the consequently obtained aisle-level air cooling effectiveness and efficiencies, contributing to more advanced data center thermal management in the future.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126528587","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}
D. K. Hall, E. Greitzer, A. Uranga, M. Drela, S. Pandya
This paper presents first-of-a-kind measurements, and complementary computations, of the flow through the propulsion system of a boundary layer ingesting, twin-engine advanced civil transport aircraft configuration. The experiments were carried out in the NASA Langley 14- by 22-foot Subsonic Tunnel, using a 1:11 scale model of the D8 “double-bubble” aircraft with electric ducted fans providing propulsive power. Overall force and moment measurements and flow field surveys at the inlet and nozzle exit planes were obtained. The computations were carried out with the NASA OVERFLOW code. The measurements and computations were conducted for a range of aircraft angles of attack and propulsor powers representing operating points during the aircraft mission. Velocity and pressure distributions at the propulsor inlet and exit, and integral inlet distortion metrics, are presented to quantify the flow non-uniformity due to boundary layer ingestion. The distorted inflow exhibits qualitative and quantitative changes over the mission, from a unidirectional stratified stagnation pressure at cruise to a streamwise vortex structure at climb conditions. The computations capture these flow features and reveal the interactions between airframe and propulsor that create these three-dimensional flow variations.
{"title":"Inlet Flow Distortion in an Advanced Civil Transport Boundary Layer Ingesting Engine Installation","authors":"D. K. Hall, E. Greitzer, A. Uranga, M. Drela, S. Pandya","doi":"10.1115/gt2021-59079","DOIUrl":"https://doi.org/10.1115/gt2021-59079","url":null,"abstract":"\u0000 This paper presents first-of-a-kind measurements, and complementary computations, of the flow through the propulsion system of a boundary layer ingesting, twin-engine advanced civil transport aircraft configuration. The experiments were carried out in the NASA Langley 14- by 22-foot Subsonic Tunnel, using a 1:11 scale model of the D8 “double-bubble” aircraft with electric ducted fans providing propulsive power. Overall force and moment measurements and flow field surveys at the inlet and nozzle exit planes were obtained. The computations were carried out with the NASA OVERFLOW code. The measurements and computations were conducted for a range of aircraft angles of attack and propulsor powers representing operating points during the aircraft mission. Velocity and pressure distributions at the propulsor inlet and exit, and integral inlet distortion metrics, are presented to quantify the flow non-uniformity due to boundary layer ingestion. The distorted inflow exhibits qualitative and quantitative changes over the mission, from a unidirectional stratified stagnation pressure at cruise to a streamwise vortex structure at climb conditions. The computations capture these flow features and reveal the interactions between airframe and propulsor that create these three-dimensional flow variations.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133989949","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}
Courtney Rider, Asad Asghar, W. Allan, G. Ingram, R. Stowe, R. Pimentel
This paper reports the investigation of a flow control strategy for an S-duct diffusers. The method incorporates stream-wise tubercles, and aims to enhance the performance of S-duct inlets by reducing the size and intensity of separated flow. These devices, bioinspired from humpback whale flippers’ leading edge protuberances, have been shown to be effective in increasing post-stall coefficients of lift of airfoils. In S-duct diffusers, the presence of convex curvature next to the separated region provides an ideal location for the installation of a tubercle-like device. The flow control effectiveness was evaluated by test-rig measurements and computational fluid dynamics (CFD) simulations of the flow in an S-duct at high subsonic flow conditions (Ma = 0.80). The S-ducts were rapid prototyped in plastic using 3D printing. Static surface pressure along the length and total pressure at the exit revealed pressure recovery, total pressure loss, swirl, and the nature of flow distortion at the S-duct exit. CFD simulations used ANSYS FLUENT with a RANS solver closed with the RKE turbulence model. The CFD simulation compared well with the test-rig data and provided useful information on flow mechanism and for understanding flow features. The performance of the baseline and variant with the flow control device was compared and flow control strategy was evaluated.
{"title":"Investigation of a Passive Flow Control Device in an S-Duct Inlet at High Subsonic Flow","authors":"Courtney Rider, Asad Asghar, W. Allan, G. Ingram, R. Stowe, R. Pimentel","doi":"10.1115/gt2021-60230","DOIUrl":"https://doi.org/10.1115/gt2021-60230","url":null,"abstract":"\u0000 This paper reports the investigation of a flow control strategy for an S-duct diffusers. The method incorporates stream-wise tubercles, and aims to enhance the performance of S-duct inlets by reducing the size and intensity of separated flow. These devices, bioinspired from humpback whale flippers’ leading edge protuberances, have been shown to be effective in increasing post-stall coefficients of lift of airfoils. In S-duct diffusers, the presence of convex curvature next to the separated region provides an ideal location for the installation of a tubercle-like device. The flow control effectiveness was evaluated by test-rig measurements and computational fluid dynamics (CFD) simulations of the flow in an S-duct at high subsonic flow conditions (Ma = 0.80). The S-ducts were rapid prototyped in plastic using 3D printing. Static surface pressure along the length and total pressure at the exit revealed pressure recovery, total pressure loss, swirl, and the nature of flow distortion at the S-duct exit. CFD simulations used ANSYS FLUENT with a RANS solver closed with the RKE turbulence model. The CFD simulation compared well with the test-rig data and provided useful information on flow mechanism and for understanding flow features. The performance of the baseline and variant with the flow control device was compared and flow control strategy was evaluated.","PeriodicalId":166333,"journal":{"name":"Volume 1: Aircraft Engine; Fans and Blowers; Marine; Wind Energy; Scholar Lecture","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114118553","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：