Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions最新文献

{"title":"Crosswind Aerodynamic Analysis Using Quasi 3D Ducts","authors":"S. Sarvankar, Adrin Issai Arasu, N. R. Vadlamani","doi":"10.1115/gt2022-82964","DOIUrl":"https://doi.org/10.1115/gt2022-82964","url":null,"abstract":"\u0000 In this paper, we address the aerodynamics of the nacelle subjected to severe crosswinds. A series of numerical simulations are carried out on a Quasi 3D duct which has been extracted from a 3D axisymmetric nacelle. The operating characteristics of the Q3D duct, total pressure profiles at fan-face and isentropic Mach number distributions over the intake lip, are demonstrated to be in encouraging agreement with the experiments. Some of the strategies to predict two different types of hysteresis which are either observed at low mass flow rates or at lower operating pressures within the duct (and hence at low Reynolds numbers) are discussed. Contrasting trends in the turbulent kinetic energy predictions of k-ω and γ-Reθ models at low system pressures are observed, which indicate that the boundary layers on the windward side of the intake lip are transitional. Finally, we discuss the possibilities of improving the off-design nacelle performance using active plasma flow control. While a low-speed separation can be eliminated using plasma actuator, controlling high speed separation remains a challenging task.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131250208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of 3D Inverse Design Method on a Transonic Compressor Stage","authors":"Luying Zhang, S. Ray, M. Zangeneh","doi":"10.1115/gt2022-82519","DOIUrl":"https://doi.org/10.1115/gt2022-82519","url":null,"abstract":"\u0000 In this paper, a three-dimensional viscous inverse design method is presented. The blade geometry is parameterized by aerodynamic variables such as blade loading, which allows direct control of the aerodynamic flow field. With a specified stacking axis and thickness distribution, the algorithm solves the flow field and blade geometry iteratively until the prescribed blade loading is matched. Meanwhile, the fast turn-around time of the inverse design method enables a substantial reduction of time and computational resources, which is particularly advantageous when the product development period is limited. The method is demonstrated through the redesign of an axial transonic compressor (Darmstadt Transonic Compressor), which has been extensively studied by experimental research and numerical simulations. The interaction between the shock wave, the tip clearance flow, and the boundary layer flow in the tip region is crucial for the compressor performance and operational stability. The redesigned compressor reduces the shock strength and the induced flow loss in the tip region through blade loading control. The performance improvement is verified by computational fluid dynamics (CFD) simulations for a stage configuration. A detailed flow field is obtained and compared to the baseline design. The loss reduction mechanism is analyzed by using entropy production rate to better understand the design impact.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132759808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Physics-Informed Neural Networks Based Solution Techniques for Internal Flows","authors":"Pascal Post, Benjamin Winhart, Francesca di Mare","doi":"10.1115/gt2022-80960","DOIUrl":"https://doi.org/10.1115/gt2022-80960","url":null,"abstract":"\u0000 In this work, we explore for the first time the possibility and potentials of employing the emerging PINNs approach in internal flow configurations, solving the steady state Euler equations in two dimensions for forward and inverse problems. In addition to a simple bump test case, the PINNs results of a highly loaded transonic linear turbine guide vane cascade are presented. For forward problems, we investigate different formulations of the transport equations and boundary conditions. Overall, PINNs approximate the solution with acceptable accuracy; however, conventional CFD methods are far superior in forward settings. Finally, we demonstrate the capabilities and the tremendous potentials of PINNs regarding hidden fluid mechanics in two distinct inverse settings, intractable for conventional CFD methods. Firstly, we infer complete flow fields based on partial, possible noisy, solution data, e.g., partial surface pressure and velocity field data; even approximating the exit condition of the cascade using only the measured blade pressure distribution is possible. Secondly, we also infer an unknown parameter of the governing equations.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130764829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Investigation of an Aggressive S-Shaped Intermediate Compressor Duct","authors":"A. Kasper, T. Dygutsch, S. Grund, M. Beversdorff, S. Håkansson, E. Nicke, M. Lejon","doi":"10.1115/gt2022-82449","DOIUrl":"https://doi.org/10.1115/gt2022-82449","url":null,"abstract":"\u0000 Reducing the fuel consumption of airplanes is one of the main research topics of the aero industry. Due to this, the bypass ratio in modern aero engines is increasing and the radial offset between the low pressure compressor (LPC) and the high pressure compressor (HPC) is getting larger. Motivated by shortening the length of the duct between the LPC and HPC, called the intermediate compressor duct (ICD), a workgroup from DLR Institute of Propulsion Technology, MTU Aero Engines AG and GKN Aerospace set up a measurement series in the new DLR ring cascade wind tunnel, that simulates a shorter and therefore aero-dynamically more aggressive s-shaped ICD. The setup consists of a full annulus channel. It provides 60 swirler blades which simulate the last rotor of the LPC, 120 LPC outlet guide vanes (OGV), 10 struts and 30 HPC inlet guide vanes (IGV). The airfoil counts are generic counts proposed for validation. Behind the OGV, there is a bleed air outlet which can be varied between 3% and 35% of the mass flow. This paper describes the highly instrumented test rig and its measurement techniques. We are able to analyze the specific flow behavior as well as determine the main ICD-performance parameter. Seven different measurement planes are located between the mentioned blade rows. The total state and the velocity (absolute value and directions) are among others measured in the plane. For each task and measurement location the best suited measurement method is selected. These are mainly multi hole probes in the main measurements planes, L2F in narrow places. The tests are conducted at eight different operating points, varying in Mach number, Reynolds number, bleed rate, stagger angle of swirler and HPC IGV. The high number of measurements leads to a profound understanding of the behavior of the ICD. The resulting conclusion is that in spite of the reduced axial length the flow through the aggressive s-shape of the ICD no separation occurs and therefore the desired performance is achieved.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121095120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Microscale-Based Methodology to Predict the Performance Degradation in Turbomachinery due to Particle Deposition","authors":"R. Friso, N. Zanini, A. Suman, N. Casari, M. Pinelli","doi":"10.1115/gt2022-82425","DOIUrl":"https://doi.org/10.1115/gt2022-82425","url":null,"abstract":"\u0000 Solid particle ingestion is one of the main causes of gas turbine compressors degradation for both heavy-duty and aero-propulsion applications. Particles that enter the engine can stick to the internal surfaces and then form deposits. These, in turn, involve a change in the surface roughness and then performance deterioration. In the literature, several strategies have been proposed in order to account for the deposits effects on compressor numerical simulations. Among the others, the most used is the mesh-morphing strategy, which consists of the modification of the computational grid according to the particle deposition. Even though it is well suited for turbine fouling, the large computational costs and complexity of this strategy are not acceptable for compressor simulations. In this work, an innovative microscale-based approach has been proposed. An axial compressor deposition experiment from the literature has been considered as the reference case to test the reliability of the presented strategy. The main advantage of this approach consists of reducing both computational costs and numerical instability since it does not need the modification of the mesh. The deposition has been modelled by means of the OSU model and the roughness influence on the fluid flow has been accounted for by using the well-known sand-grain-roughness height (ks). Efforts have been made to find the ks correlation that best represents a fouled surface. The presented strategy enables the prediction of the fouling effects on axial flow compressors, and the prediction of the performance losses during the operation.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123164989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigations of the Unsteady Aerodynamic Characteristics for Intakes at Crosswind","authors":"Tommaso Piovesan, Zhang Wenqiang, M. Vahdati, P. Zachos","doi":"10.1115/gt2022-82149","DOIUrl":"https://doi.org/10.1115/gt2022-82149","url":null,"abstract":"\u0000 The ground vortex generated in front of an intake operating near the ground and subjected to crosswind is investigated using CFD and compared to the experiments. The flow field of a scale-model intake is numerically simulated with both steady and unsteady approach, with the aim of predicting ground vortex effects and to characterize the vortex unsteady behaviour. The experimental results showed that for an intake near the ground under crosswind the ground vortex that forms under the intake and the in-duct separation, when present, exhibit unsteady behaviour that becomes stronger as the crosswind velocity is increased. The simulations indicate that a steady-state approach only partially reproduces the time-averaged ground vortex characteristics and in-duct distortion losses, while an unsteady approach shows a lower level of unsteadiness compared to the experimental observations. The consequences of the unsteady flow in the intake on the fan aerodynamic and aeroelastic stability are finally discussed to reinforce that these can result in significant non-synchronous vibration (NSV) and loss of stall margin which cannot be adequately assessed if no unsteady component of the inlet distortions is taken into account.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126153731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aerodynamic Assessment of Turbine Center Frames and Turbine Vane Frames Under the Influence of Purge Flows","authors":"F. Merli, Asim Hafizovic, Nicolas Krajnc, Malte Schien, A. Peters, F. Heitmeir, E. Göttlich","doi":"10.1115/gt2022-82502","DOIUrl":"https://doi.org/10.1115/gt2022-82502","url":null,"abstract":"\u0000 This paper investigates and compares the aerodynamics of two state-of-the-art configurations for the intermediate turbine duct (ITD) in a turbofan engine: the turbine center frame (TCF), which is typical of conventional dual-spool engines and features symmetric aerodynamic strut fairings, and the turbine vane frame (TVF), which integrates a set of turning struts and splitters directly in the duct, thus enabling length and weight benefits at engine system level.\u0000 The measurement data utilized for the analysis are a product of almost ten years of research at Graz University of Technology, involving multiple test campaigns with either TCF or TVF setups at consistent inlet conditions. The experimental tests are carried out in the Transonic Test Turbine Facility at the Institute of Thermal Turbomachinery and Machine Dynamics (Graz University of Technology). All test vehicles include not only the ITD (TCF or TVF), but also the last High-Pressure Turbine (HPT) stage and the first Low-Pressure Turbine (LPT) vane or blade row, in order to ensure engine-representative conditions at the duct inlet and outlet sections. For the same purpose, the test facility supplies all the stator-rotor cavities with purge air, with independent control of temperature and mass flows for each cavity.\u0000 The measurements are performed with pneumatic probes (five-hole probes, Kiel-head rakes) at the inlet and outlet of the ITDs, for three different HPT purge flow rates. The aerodynamic comparison between TCF and TVF setups is based on three key topics: duct inlet and outlet flow fields, duct total pressure losses and duct aerodynamic excitation on the LPT rotor blades. For each one of them, the sensitivity to HPT purge variation in both configurations is evaluated.\u0000 Due to the presence of turning struts and splitters inside the ITD, the TVF shows a more complex outlet flow field than the TCF, characterized by the interaction of HPT and TVF secondary phenomena. The TVF total pressure loss is less sensitive to purge variation compared to an advanced TCF design with high casing slope. While the weaker TVF loss derivative to HPT purge may provide off-design operating point benefits relative to a TCF-based engine, the increased level of flow nonuniformity at the TVF exit, distributed over a wider range of engine orders, represents a design challenge for the first-stage LPT rotor.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"151 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121260825","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Objective Development of Machine-Learnt Closures for Fully Integrated Transition and Wake Mixing Predictions in Low Pressure Turbines","authors":"Harshal D. Akolekar, F. Waschkowski, R. Pacciani, Yaomin Zhao, R. Sandberg","doi":"10.1115/gt2022-81091","DOIUrl":"https://doi.org/10.1115/gt2022-81091","url":null,"abstract":"\u0000 In low pressure turbines (LPT), due to the low Reynolds number a large part of the blade boundary layer remains laminar and transition may occur due to flow separation. The boundary layer details at the blade trailing edge can change substantially depending on the transition region topology and can strongly influence the wake mixing occurring downstream. Accurately predicting these flow phenomena still poses a challenge for Reynolds averaged Navier-Stokes (RANS) and unsteady RANS methods. In this work a recently developed computational fluid dynamics (CFD) driven machine learning framework featuring multi-expression, multi-objective optimization is exploited for the first time to simultaneously develop transition models and turbulence closures in a fully coupled way, aimed at improving both transition and wake mixing predictions in LPTs. The T106A blade cascade with an isentropic Reynolds number of 100,000 is adopted as a training case. The baseline transition model is based on a laminar kinetic energy transport approach, and the machine learning approach is used to reformulate the source terms as functions of suitably defined non-dimensional ratios. Additionally, machine learning based explicit algebraic Reynolds stress models are used to improve wake mixing predictions, making use of a specifically and newly developed wake sensing function based strategy that allows an automated zonal application of the developed models. It is shown that both on-blade performance and wake mixing can be predicted accurately with data-driven transition and turbulence models that have benefited from CFD feedback in their development, ensuring that their mutual interactions are captured.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124099778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low Mach Preconditioning for Turbomachinery Flow Simulations With Cavities and Variable Gas Compositions","authors":"P. Sivel, C. Frey, E. Kügeler, Markus Keil","doi":"10.1115/gt2022-79369","DOIUrl":"https://doi.org/10.1115/gt2022-79369","url":null,"abstract":"\u0000 The optimization of turbomachines increasingly relies on highly accurate numerical performance predictions. Loss predictions require the cavities of the machine to be included in numerical simulations. Commonly, in cavities, the velocity of the simulated fluid is small. For density-based solvers, this results in slow convergence and inaccurate computations. Further, the fluid in cavities is often composed of several gases. This paper presents the low Mach preconditioning method for multi-component thermally perfect gas of DLR’s inhouse solver TRACE.\u0000 Two low Mach academic test cases, a lid driven cavity and an air and exhaust gas mixing layer, are computed to validate the preconditioner. Both test cases show an accelarated convergence and an improved accuracy, when preconditioning is used.\u0000 A 1.5 stage low-pressure turbine rig with a labyrinth seal is computed with thermally perfect air. The result shows a good agreement with the experimental reference. The fluid is then changed to exhaust gas, and two air inflows are added in the labyrinth seal, to analyze the effect of low Mach preconditioning on the mixing of the two gases. The preconditioned computation shows an improved convergence in the cavity. Moreover, the wall temperature and the gas distribution in the cavity differ, when preconditioning is applied.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132776688","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Cavity Leakage Effects on Coupled Non-Axisymmetric Endwall-Airfoil Optimization in a Low-Speed Compressor Tandem Stator","authors":"Mattia Straccia, Samuele Giannini, V. Gümmer","doi":"10.1115/gt2022-82418","DOIUrl":"https://doi.org/10.1115/gt2022-82418","url":null,"abstract":"\u0000 This paper aims at describing the effects of the hub leakage flow on non-axisymmetric endwall contouring and airfoil optimization in a highly-loaded tandem vane, in order to give a better understanding of the potential of the approach, independently of the seal leakage. Since its first applications on highly-loaded compressor stages, it has been highlighted how the non-axisymmetric contouring can be effective in manipulating the secondary flow behavior close to the endwalls. Many cases have proven its positive influence on the flow field behavior for single and tandem vanes, drawing general guidelines for the preliminary design phase, thanks to the usage of optimization tools. An interesting question still to be addressed in a general sense is at which specific conditions designers should rely on endwall contouring and when they should not, considering the obvious additional manufacturing expenses associated. First studies on this subject, assumed the interchangeability of non-axisymmetric endwall contouring with radial stacking laws. Nowadays, fully 3D optimized airfoil geometries being state of the art, it appears evident that new general guidelines are needed. In this context, the influence of the hub leakage flow on the definition and effectiveness of the endwall contouring is investigated, isolating its beneficial influences, which will be described independently of the topology of the low momentum fluid present close to the endwalls. Therefore, the reference geometry is varied in mass leakage flow by varying the geometry of the cavity of the shrouded tandem stator arrangement. Then, the new configuration is optimized via non-axisymmetric endwall contouring and hub airfoil profile optimization, carried out by means of a meta-heuristic approach. The investigation based on total pressure losses and static polytropic efficiency will show the break-even point of the beneficial influence of the non-axisymmetric contour with respect to the reducing leakage mass flow. Moreover, the change of design strategies adopted by the optimizer among the different flow field configurations shall serve as a reference guide for every future design choice incorporating non-axisymmetric endwall contouring.","PeriodicalId":191970,"journal":{"name":"Volume 10C: Turbomachinery — Design Methods and CFD Modeling for Turbomachinery; Ducts, Noise, and Component Interactions","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132958510","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}