Journal articles: 'Turbomachinery; CFD'

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Blech, R. A., E. J. Milner, A. Quealy, and S. E. Townsend. "Turbomachinery CFD on parallel computers." Computing Systems in Engineering 3, no. 6 (December 1992): 613–23. http://dx.doi.org/10.1016/0956-0521(92)90013-9.

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Denton, J. D., and W. N. Dawes. "Computational fluid dynamics for turbomachinery design." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 213, no. 2 (February 1, 1998): 107–24. http://dx.doi.org/10.1243/0954406991522211.

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Computational fluid dynamics (CFD) probably plays a greater part in the aerodynamic design of turbomachinery than it does in any other engineering application. For many years the design of a modern turbine or compressor has been unthinkable without the help of CFD and this dependence has increased as more of the flow becomes amenable to numerical prediction. The benefits of CFD range from shorter design cycles to better performance and reduced costs and weight. This paper presents a review of the main CFD methods in use, discusses their advantages and limitations and points out where further developments are required. The paper is concerned with the application of CFD and does not describe the numerical methods or turbulence modelling in any detail.

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Chew, John W., and Nicholas J. Hills. "Computational fluid dynamics for turbomachinery internal air systems." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 365, no. 1859 (May 22, 2007): 2587–611. http://dx.doi.org/10.1098/rsta.2007.2022.

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Considerable progress in development and application of computational fluid dynamics (CFD) for aeroengine internal flow systems has been made in recent years. CFD is regularly used in industry for assessment of air systems, and the performance of CFD for basic axisymmetric rotor/rotor and stator/rotor disc cavities with radial throughflow is largely understood and documented. Incorporation of three-dimensional geometrical features and calculation of unsteady flows are becoming commonplace. Automation of CFD, coupling with thermal models of the solid components, and extension of CFD models to include both air system and main gas path flows are current areas of development. CFD is also being used as a research tool to investigate a number of flow phenomena that are not yet fully understood. These include buoyancy-affected flows in rotating cavities, rim seal flows and mixed air/oil flows. Large eddy simulation has shown considerable promise for the buoyancy-driven flows and its use for air system flows is expected to expand in the future.

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Hills, N. "Achieving high parallel performance for an unstructured unsteady turbomachinery CFD code." Aeronautical Journal 111, no. 1117 (March 2007): 185–93. http://dx.doi.org/10.1017/s0001924000004449.

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This paper describes the work done to achieve high parallel performance for an unstructured, unsteady turbomachinery computational fluid dynamics (CFD) code. The aim of the work described here is to be able to scale problems to the thousands of processors that current and future machine architectures will provide. The CFD code is in design use in industry and is also used as a research tool at a number of universities. High parallel scalability has been achieved for a range of turbomachinery test cases, from steady-state hexahedral mesh cases to fully unsteady unstructured mesh cases. This has been achieved by a combination of code modification and consideration of the parallel partitioning strategy and resulting load balancing. A sliding plane option is necessary to run fully unsteady multistage turbomachinery test cases and this has been implemented within the CFD code. Sample CFD calculations of a full turbine including parts of the internal air system are presented.

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Adamczyk, John J. "Aerodynamic Analysis of Multistage Turbomachinery Flows in Support of Aerodynamic Design." Journal of Turbomachinery 122, no. 2 (February 1, 1999): 189–217. http://dx.doi.org/10.1115/1.555439.

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This paper summarizes the state of 3D CFD based models of the time-averaged flow field within axial flow multistage turbomachines. Emphasis is placed on models that are compatible with the industrial design environment and those models that offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models free of aerodynamic input from semiempirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures that can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines that help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time-averaged flow models. [S0889-504X(00)02002-X]

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Ishida, H., N. Yamasaki, and M. Aotsuka. "Linear Unsteady CFD of Vibrating Blades of Turbomachinery." Procedia Engineering 67 (2013): 197–206. http://dx.doi.org/10.1016/j.proeng.2013.12.019.

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Koptilin, R. M., and A. V. Gaynutdinov. "Market overview CAE solutions for hydro, fluid dynamics of turbomachines." Informacionno-technologicheskij vestnik 13, no. 3 (September 30, 2017): 94–105. http://dx.doi.org/10.21499/2409-1650-2017-3-94-105.

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In this article the review of the market of software complexes for solving the problems of hydro- and gas dynamics of turbomachines is given. In the course of the work, CAE systems were analyzed to solve problems in this area. In the course of the analysis, the main possibilities, physical models, methods of solving problems used in this software were considered. Comparison of the functional of CFD analysis systems was carried out, the same and distinctive properties of the modeling systems of processes occurring in turbomachinery were identified.

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Dawes, W. N. "Turbomachinery computational fluid dynamics: asymptotes and paradigm shifts." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 365, no. 1859 (May 22, 2007): 2553–85. http://dx.doi.org/10.1098/rsta.2007.2021.

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This paper reviews the development of computational fluid dynamics (CFD) specifically for turbomachinery simulations and with a particular focus on application to problems with complex geometry. The review is structured by considering this development as a series of paradigm shifts, followed by asymptotes. The original S1–S2 blade–blade-throughflow model is briefly described, followed by the development of two-dimensional then three-dimensional blade–blade analysis. This in turn evolved from inviscid to viscous analysis and then from steady to unsteady flow simulations. This development trajectory led over a surprisingly small number of years to an accepted approach—a ‘CFD orthodoxy’. A very important current area of intense interest and activity in turbomachinery simulation is in accounting for real geometry effects, not just in the secondary air and turbine cooling systems but also associated with the primary path. The requirements here are threefold: capturing and representing these geometries in a computer model; making rapid design changes to these complex geometries; and managing the very large associated computational models on PC clusters. Accordingly, the challenges in the application of the current CFD orthodoxy to complex geometries are described in some detail. The main aim of this paper is to argue that the current CFD orthodoxy is on a new asymptote and is not in fact suited for application to complex geometries and that a paradigm shift must be sought. In particular, the new paradigm must be geometry centric and inherently parallel without serial bottlenecks. The main contribution of this paper is to describe such a potential paradigm shift, inspired by the animation industry, based on a fundamental shift in perspective from explicit to implicit geometry and then illustrate this with a number of applications to turbomachinery.

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Chew, J. W. "Developments in turbomachinery internal air systems." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 1 (December 1, 2008): 189–234. http://dx.doi.org/10.1243/09544062jmes1140.

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Development of turbomachinery technology, including aircraft propulsion, has been an outstanding achievement of the last 50 years and, as illustrated by Ruffles in his paper ‘The future of aircraft propulsion’ (2000), further advances are expected in the future. Here, one particular aspect of turbomachinery technology, the internal air system is considered. An article by Dixon et al., published by the Institution of Mechanical Engineers in 2004, shows how computational modelling has become central to the design process and the importance of the internal air system in engine design. Bayley and Conway's 1964 paper, motivated by shortcomings in industrial design methods and understanding, was one of the first investigations of flow and heat transfer in rotating disc cavities typical of internal air systems. During the study, a theoretical or numerical treatment was considered intractable and so experiments were undertaken. These paved the way for an extensive research in this area. Today, the use of computational fluid dynamics (CFD) in industry for internal air flow prediction is commonplace. In this review, it is shown that the unshrouded disc cavity flow considered by Bayley and Conway is still challenging for modern CFD methods, and so the experimental data remain of interest to researchers in the field.

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Pujol, T., L. Montoro, M. Pelegrí, and J. R. González. "Learning hydraulic turbomachinery with computational fluid dynamics (CFD) codes." Computer Applications in Engineering Education 21, no. 4 (December 29, 2010): 684–90. http://dx.doi.org/10.1002/cae.20513.

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Han, Hai, and Yoichi Yokoyama. "Recent CFD Applications of the CFX Software to Turbomachinery." Proceedings of the Fluids engineering conference 2003 (2003): 62. http://dx.doi.org/10.1299/jsmefed.2003.62.

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Ferguson, T., and R. McGlynn. "Validation of Turbomachinery Computational Fluid Dynamic Models Using Laser Velocimetry." Journal of the IEST 42, no. 6 (November 17, 1999): 19–25. http://dx.doi.org/10.17764/jiet.42.6.y0162422x862g242.

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Computational fluid dynamic (CFD) codes are powerful tools for flow field modeling. The codes, however, must be calibrated with data from actual flows if the predictions of the analysis are to be applied with confidence. Laser velocimetry is one method whereby the predictions of the codes can be anchored with accurate, noninvasive flow-field data. This paper explores the process from initial CFD concerns to the application of the velocimeter in the test facility.

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Tucci, Francesco Aldo, Giovanni Delibra, and Alessandro Corsini. "Development of a data-driven model for turbulent heat transfer in turbomachinery." E3S Web of Conferences 197 (2020): 11006. http://dx.doi.org/10.1051/e3sconf/202019711006.

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Machine Learning (ML) algorithms have become popular in many fields, including applications related to turbomachinery and heat transfer. The key properties of ML are the capability to partially tackle the problem of slowing down of Moore’s law and to dig-out correlations within large datasets like those available on turbomachinery. Data come from experiments and simulations with different degree of accuracy, according to the test-rig or the CFD approach. When dealing with modelling of turbulent flows in turbomachinery there is a constant trade-off between accuracy and computational costs, but starting from the large amount of data on turbomachinery performance, with ML it is possible to train a learner to correct and improve CFD. The aim of this work is to investigate an innovative data-driven approach that could lead to a significant improvement in the analysis of heat transfer in turbulent flows. The effects of Reynolds number and wall temperature on heat transfer for a double forward-facing step with two squared obstacles were investigated by numerical simulations carried out in OpenFOAM. Then a machine-learnt model was derived using a regression algorithm. The results of regressor showed that a data-driven approach can effectively predict results of the RANS model.

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Rosa, Henrique Marcio Pereira, and Gabriela Pereira Toledo. "CFD tool application in predicting the behavior of a centrifugal fan designed by one-dimensional theory." Research, Society and Development 10, no. 12 (September 25, 2021): e412101219653. http://dx.doi.org/10.33448/rsd-v10i12.19653.

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Computational fluid dynamics (CFD) is the most current technology in the fluid flow study. Experimental methods for predicting the turbomachinery performance involve greater time consumption and financial resources compared to the CFD approach. The purpose of this article is to present the analysis of CFD simulation results in a centrifugal fan. The impeller was calculated using the one-dimensional theory and the volute the principle of constant angular momentum. The ANSYS-CFX software was used for the simulation. The turbulence model adopted was the SST. The simulation provided the characteristic curves, the pressure and velocity distribution, and the static and total pressure values at impeller and volute exit. An analysis of the behavior of the pressure plots, and the loss and recovery of pressure in the volute was performed. The results indicated the characteristic curves, the pressure and velocity distribution were consistent with the turbomachinery theory. The pressure values showed the static pressure at volute exit was smaller than impeller exit for some flow rate. It caused the pressure recovery coefficient negative. This work indicated to be possible design a centrifugal fan applying the one-dimensional theory and optimize it with the CFD tool.

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TANI, Naoki, Jun HIROMATSU, Masaharu Uchiumi, and Nobuhiro YAMANISHI. "J101021 Investigation on CFD methodology for turbomachinery with whirling motion." Proceedings of Mechanical Engineering Congress, Japan 2013 (2013): _J101021–1—_J101021–2. http://dx.doi.org/10.1299/jsmemecj.2013._j101021-1.

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Perreault, Maxime, Sina Hamzehlouia, and Kamran Behdinan. "Application of computational fluid dynamics for thermohydrodynamic analysis of high-speed squeeze-film dampers." Transactions of the Canadian Society for Mechanical Engineering 43, no. 3 (September 1, 2019): 306–21. http://dx.doi.org/10.1139/tcsme-2018-0060.

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In high-speed turbomachinery, the presence of rotor vibrations, which produce undesirable noise or shaft deflection and losses in performance, has brought up the need for the application of a proper mechanism to attenuate the vibration amplitudes. Squeeze-film dampers (SFDs) are a widely employed solution to the steady-state vibrations in high-speed turbomachinery. SFDs contain a thin film of lubricant that is susceptible to changes in temperature. For this reason, the analysis of thermohydrodynamic (THD) effects on the SFD damping properties is essential. This paper develops a computational fluid dynamics (CFD) model to analyze the THD effects in SFDs, and enabling the application of CFD analysis to be a base-line for validating the accuracy of analytical THD SFD models. Specifically, the CFD results are compared against numerical simulations at different operating conditions, including eccentricity ratios and journal whirl speeds. The comparisons demonstrate the effective application of CFD for THD analysis of SFDs. Additionally, the effect of the lubricant THDs on the viscosity, maximum and mass-averaged temperature, as well as heat generation rates inside the SFD lubricant are analyzed. The temperature of the lubricant is seen to rise with increasing whirl speed, eccentricity ratios, damper radial clearance, and shaft radii.

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Herrick, Gregory, and Jen-Ping Chen. "Methods for Computationally Efficient Structured CFD Simulations of Complex Turbomachinery Flows." International Journal for Computational Methods in Engineering Science and Mechanics 12, no. 4 (July 2011): 176–83. http://dx.doi.org/10.1080/15502287.2011.580829.

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Michaud, Mathias, Petro Jr Milan, and Huu Duc Vo. "Low-Cost Rotating Experimentation in Compressor Aerodynamics Using Rapid Prototyping." International Journal of Rotating Machinery 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/8518904.

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With the rapid evolution of additive manufacturing, 3D printed parts are no longer limited to display purposes but can also be used in structural applications. The objective of this paper is to show that 3D prototyping can be used to produce low-cost rotating turbomachinery rigs capable of carrying out detailed flow measurements that can be used, among other things, for computational fluid dynamics (CFD) code validation. A fully instrumented polymer two-stage axial-mixed flow compressor test rig was designed and fabricated with stereolithography (SLA) technology by a team of undergraduate students as part of a senior-year design course. Experiments were subsequently performed on this rig to obtain both the overall pressure rise characteristics of the compressor and the stagnation pressure distributions downstream of the blade rows for comparison with CFD simulations. In doing so, this work provides a first-of-a-kind assessment of the use of polymer additive technology for low-cost rotating turbomachinery experimentation with detailed measurements.

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Brozowski, L. A., T. V. Ferguson, and L. Rojas. "Impeller Flow Field Laser Velocimeter Measurements." International Journal of Rotating Machinery 2, no. 3 (1996): 149–59. http://dx.doi.org/10.1155/s1023621x96000024.

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Development of Computational Fluid Dynamics (CFD) computer codes for complex turbomachinery affords a complete three-dimensional (3-D) flow field description. While significant improvements in CFD have been made due to improvements in computers, numerical algorithms, and physical modeling, a limited experimental database for pump CFD code validation exists.Under contract (NAS8-38864) to the National Aeronautics and Space Administration (NASA) at Marshall Space Flight Center (MSFC) a test program was undertaken at Rocketdyne to obtain benchmark data for typical rocket engine pump geometry. Nonintrusive velocity data were obtained with a laser two-focus velocimeter. Extensive laser surveys at the inlet and discharge of a Rocketdyne-designed impeller were performed. Static pressures were measured at key locations to provide boundary conditions for CFD code validation.

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Cravero, C., and A. Satta. "Comparison of Semi-Empirical Correlations and a Navier-Stokes Method for the Overall Performance Assessment of Turbine Cascades." Journal of Fluids Engineering 125, no. 2 (March 1, 2003): 308–14. http://dx.doi.org/10.1115/1.1539869.

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Turbomachinery flows can nowadays be investigated using several numerical techniques to solve the full set of Navier-Stokes equations; nevertheless the accuracy in the computation of losses is still a challenging topic. The paper describes a time-marching method developed by the authors for the integration of the Reynolds averaged Navier-Stokes equations in turbomachinery cascades. The attention is focused on turbine sections and the computed aerodynamic performances (outlet flow angle, profile loss, etc.,) are compared to experimental data and/or correlations. The need for this kind of CFD analysis tools is stressed for the substitution of standard correlations when a new blade is designed.

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Kumar, Vikas, Keshar Patel, and Vikram P. Rathod. "Blade Stresses and CFD Analysis of Axial Gas Turbine." Applied Mechanics and Materials 592-594 (July 2014): 1011–14. http://dx.doi.org/10.4028/www.scientific.net/amm.592-594.1011.

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This work deals with study, investigation, design and analysis structure of 5 stages axial flow gas turbine with AxSTREAM software suite. AxSTREAM turbomachinery suite, with few boundary conditions generating solutions precisely and very fast in preliminary design with ideal point. For that point including losses design the streamline flow path and converging results of CFD analysis and visualization the thermodynamic parameters. Stress and FEM analysis of a single stage and study of von mises stresses distribution. Static and vibration analysis of turbine blade with difference frequency and temperature. Natural frequency, rotor speed study with operating speed and vibration mode with Campbell diagram.

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Corsini, Alessandro, Franco Rispoli, and Andrea Santoriello. "Quadratic Petrov‐Galerkin finite elements for advective‐reactive features in turbomachinery CFD." International Journal of Numerical Methods for Heat & Fluid Flow 15, no. 8 (December 2005): 894–925. http://dx.doi.org/10.1108/09615530510625147.

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Sawa, Yoshiyuki. "CFD Design and Optimization for Turbomachinery by FINE/Turbo and FINE/Design3D." Proceedings of the Fluids engineering conference 2003 (2003): 64. http://dx.doi.org/10.1299/jsmefed.2003.64.

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Camp, T. R., and H. W. Shin. "Turbulence Intensity and Length Scale Measurements in Multistage Compressors." Journal of Turbomachinery 117, no. 1 (January 1, 1995): 38–46. http://dx.doi.org/10.1115/1.2835642.

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This paper describes the measurement and processing of turbulence data from multistage low-speed compressors. Measurements were made at the same relative positions in three four-stage compressors, each having different levels of the design stage loading coefficient. A new method of data processing to calculate turbulence intensities and integral length scales is outlined. Using this method, integral length scales have been measured in turbomachinery flows for the first time. It is shown how the turbulence intensity and integral length scale vary with position in the blade passage, with changing flow coefficient and with the value of the design stage loading coefficient. The results have been used to specify representative inlet conditions for experimental rigs and to improve the application of CFD turbulence models to turbomachinery modeling.

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YAMADA, Kazutoyo, Ken-ichi FUNAZAKI, and Jun OGASAWARA. "211 Application of LBM to Separated Flow in Turbomachinery." Proceedings of the JSME annual meeting 2005.2 (2005): 107–8. http://dx.doi.org/10.1299/jsmemecjo.2005.2.0_107.

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Rose, M. G., and N. W. Harvey. "Turbomachinery Wakes: Differential Work and Mixing Losses." Journal of Turbomachinery 122, no. 1 (February 1, 1999): 68–77. http://dx.doi.org/10.1115/1.555429.

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In this paper the mixing of stator wakes in turbomachinery is considered. An extension is made to the existing model of Denton (1993, ASME J. Turbomach., 115, pp. 621–656) which addresses the effects of acceleration before mixing. Denton showed that if a total pressure wake was accelerated, mixing loss diminished, and vice versa. Here a total temperature wake is shown to exhibit a reverse trend. An attempt is also made to understand better the work transfer process between a stator wake and a rotor. The paper concentrates on axial turbines, but a brief look at compressors is included. It is argued that the free-stream work is not the same as the wake work, and the concept of “Differential Work” is introduced. A simple steady velocity triangle based model is proposed to give an estimate of the ratio of wake work to free-stream work (μ, see later). The model is compared to an unsteady CFD result to offer some verification of the assumptions. It is concluded that the rotodynamic work process tends to reduce total pressure wake depths in turbines and compressors and therefore mixing losses. The mixing loss due to total temperature wakes is less strongly affected by the differential work process. [S0889-504X(00)00801-1]

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Northall, John D. "The Influence of Variable Gas Properties on Turbomachinery Computational Fluid Dynamics." Journal of Turbomachinery 128, no. 4 (February 1, 2005): 632–38. http://dx.doi.org/10.1115/1.2221324.

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This paper describes the inclusion of variable gas properties within a Reynolds average Navier-Stokes solver for turbomachinery and its application to multistage turbines. Most current turbomachinery computational fluid dynamics (CFD) models the gas as perfect with constant specific heats. However, the specific heat at constant pressure CP can vary significantly. This is most marked in the turbine where large variations of temperature are combined with variations in the fuel air ratio. In the current model CP is computed as a function of the local temperature and fuel air ratio using polynomial curve fits to represent the real gas behavior. The importance of variable gas properties is assessed by analyzing a multistage turbine typical of the core stages of a modern aeroengine. This calculation includes large temperature variations due to radial profiles at inlet, the addition of cooling air, and work extraction through the machine. The calculation also includes local variations in fuel air ratio resulting from the inlet profile and the dilution of the mixture by the addition of coolant air. A range of gas models is evaluated. The addition of variable gas properties is shown to have no significant effect on the convergence of the algorithm, and the extra computational costs are modest. The models are compared with emphasis on the parameters of importance in turbine design, such as capacity, work, and efficiency. Overall the effect on turbine performance prediction of including variable gas properties in three-dimensional CFD is found to be small.

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Vicéns, José Luis, and Blas Zamora. "Using CFD as a support tool for the initial study of Hydraulic Turbomachinery." Modelling in Science Education and Learning 7 (March 30, 2014): 49. http://dx.doi.org/10.4995/msel.2014.2091.

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Ampellio, Enrico, Francesco Bertini, Andrea Ferrero, Francesco Larocca, and Luca Vassio. "Turbomachinery design by a swarm-based optimization method coupled with a CFD solver." Advances in aircraft and spacecraft science 3, no. 2 (April 25, 2016): 149–70. http://dx.doi.org/10.12989/aas.2016.3.2.149.

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Hall, K. C., R. Florea, and P. J. Lanzkron. "A Reduced Order Model of Unsteady Flows in Turbomachinery." Journal of Turbomachinery 117, no. 3 (July 1, 1995): 375–83. http://dx.doi.org/10.1115/1.2835672.

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A novel technique for computing unsteady flows about turbomachinery cascades is presented. Starting with a frequency domain CFD description of unsteady aerodynamic flows, we form a large, sparse, generalized, non-Hermitian eigenvalue problem that describes the natural modes and frequencies of fluid motion about the cascade. We compute the dominant left and right eigenmodes and corresponding eigenfrequencies using a Lanczos algorithm. Then, using just a few of the resulting eigenmodes, we construct a reduced order model of the unsteady flow field. With this model, one can rapidly and accurately predict the unsteady aerodynamic loads acting on the cascade over a wide range of reduced frequencies and arbitrary modes of vibration. Moreover, the eigenmode information provides insights into the physics of unsteady flows. Finally we note that the form of the reduced order model is well suited for use in active control of aeroelastic and aeroacoustic phenomena.

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Iliev, Rossen. "A CFD analysis of the performance characteristics of different Darrieus turbine runners." E3S Web of Conferences 207 (2020): 02012. http://dx.doi.org/10.1051/e3sconf/202020702012.

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This paper presents the capabilities of analyzing different Darrieus wind turbine runners with the computer program Ansys Fluent. A K-omega turbulence model was used in the case of a two-dimensional flow with a suitable computational grid around the profile of the blades. The obtained theoretical performance characteristics were validated on test rig №7 (Wind Turbines) in the Laboratory of Hydropower and Hydraulic Turbomachinery (HEHT Lab) at the Technical University of Sofia. The data analysis shows that it’s possible to predict the performance characteristic and the optimum operating regime of the Darrieus wind turbine.

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Seshadri, P., S. Yuchi, G. T. Parks, and S. Shahpar. "Supporting multi-point fan design with dimension reduction." Aeronautical Journal 124, no. 1279 (July 27, 2020): 1371–98. http://dx.doi.org/10.1017/aer.2020.50.

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AbstractMotivated by the idea of turbomachinery active subspace performance maps, this paper studies dimension reduction in turbomachinery 3D CFD simulations. First, we show that these subspaces exist across different blades—under the same parametrisation—largely independent of their Mach number or Reynolds number. This is demonstrated via a numerical study on three different blades. Then, in an attempt to reduce the computational cost of identifying a suitable dimension reducing subspace, we examine statistical sufficient dimension reduction methods, including sliced inverse regression, sliced average variance estimation, principal Hessian directions and contour regression. Unsatisfied by these results, we evaluate a new idea based on polynomial variable projection—a non-linear least-squares problem. Our results using polynomial variable projection clearly demonstrate that one can accurately identify dimension reducing subspaces for turbomachinery functionals at a fraction of the cost associated with prior methods. We apply these subspaces to the problem of comparing design configurations across different flight points on a working line of a fan blade. We demonstrate how designs that offer a healthy compromise between performance at cruise and sea-level conditions can be easily found by visually inspecting their subspaces.

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Casoni, Marco, and Ernesto Benini. "A Review of Computational Methods and Reduced Order Models for Flutter Prediction in Turbomachinery." Aerospace 8, no. 9 (September 2, 2021): 242. http://dx.doi.org/10.3390/aerospace8090242.

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Aeroelastic phenomena in turbomachinery are one of the most challenging problems to model using computational fluid dynamics (CFD) due to their inherent nonlinear nature, the difficulties in simulating fluid–structure interactions and the considerable computational requirements. Nonetheless, accurate modelling of self-sustained flow-induced vibrations, known as flutter, has proved to be crucial in assessing stability boundaries and extending the operative life of turbomachinery. Flutter avoidance and control is becoming more relevant in compressors and fans due to a well-established trend towards lightweight and thinner designs that enhance aerodynamic efficiency. In this paper, an overview of computational techniques adopted over the years is first presented. The principal methods for flutter modelling are then reviewed; a classification is made to distinguish between classical methods, where the fluid flow does not interact with the structure, and coupled methods, where this interaction is modelled. The most used coupling algorithms along with their benefits and drawbacks are then described. Finally, an insight is presented on model order reduction techniques applied to structure and aerodynamic calculations in turbomachinery flutter simulations, with the aim of reducing computational cost and permitting treatment of complex phenomena in a reasonable time.

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Polacsek, C., and S. Burguburu. "Fan Interaction Noise Predictions Using RANS-BEM Coupling." International Journal of Aeroacoustics 4, no. 1-2 (January 2005): 153–67. http://dx.doi.org/10.1260/1475472053729987.

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A source-to-far-field computation procedure aiming at predicting the noise generated by rotor-stator fan interactions and inlet noise radiation is presented here. It is applied to the NLR turbofan model, tested in DNW-LLF anechoic chamber under the framework of DUCAT project. The unsteady aerodynamic input for the acoustic computation is obtained using a 3D RANS code, CANARI, developed at ONERA for turbomachinery applications. The CFD solutions are coupled, using a modal expansion approach, to a BEM code, solving the Helmholtz equation in an arbitrary bounded space. A single interacting cut-on mode amplitude is either directly deduced from experiment or provided by post-processing the CFD data. With this approach, the predicted noise radiation can be related to the directivity patterns measured at several axial positions upstream of the turbofan inlet. A fairly good agreement is found using both experimental and CFD input data.

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Cai, Jin, Qing Ze Xu, and Zheng Wang. "Flutter Analysis of Compressor Blade Based on CFD/CSD." Applied Mechanics and Materials 50-51 (February 2011): 8–12. http://dx.doi.org/10.4028/www.scientific.net/amm.50-51.8.

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Based on the CFD/CSD (Computational Fluid Dynamics / Computational Structural Dynamics) algorithm, flutter characteristic and fluid structure interaction (FSI) problems of turbomachinery blades were studied in present paper. The three-dimensional unsteady Navier-Stokes equations and three-dimensional structural model were solved by the finite volume method and the finite element method, respectively. High accuracy in calculation and data exchange were gained by using load transfer, deformation tracking and synchronization between two solvers. The procedure successfully simulated the aeroelastic responses of a high performance fan rotor, NASA Rotor 67, over a range of operational conditions, and the results were compared with the experiment. The results show that the flutter mechanics of the compressor blade could be illustrated based on mean pressure and the distribution of cycle work, which is helpful for the decision of compressor stability.

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Praisner, T. J., and J. P. Clark. "Predicting Transition in Turbomachinery—Part I: A Review and New Model Development." Journal of Turbomachinery 129, no. 1 (March 1, 2004): 1–13. http://dx.doi.org/10.1115/1.2366513.

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Here we report on an effort to include an empirically based transition modeling capability in a Reynolds Averaged Navier-Stokes solver. Well known empirical models for both attached- and separated-flow transition were tested against cascade data and found unsuitable for use in turbomachinery design. Consequently, a program was launched to develop models with sufficient accuracy for use in design. As a first step, accurate prediction of free stream turbulence development was identified as a prerequisite for accurate modeling. Additionally, a demonstrated capability to capture the effects of free stream turbulence on pre-transitional boundary layers became an impetus for the work. A computational fluid dynamics (CFD)-supplemented database of 104 experimental cascade cases was constructed to explore the development of new correlations. Dimensional analyses were performed to guide the work, and appropriate non-dimensional parameters were then extracted from CFD predictions of the laminar boundary layers existing on the airfoil surfaces prior to either transition onset or incipient separation. For attached-flow transition, onset was found to occur at a critical ratio of the boundary-layer diffusion time to a time scale associated with the energy-bearing turbulent eddies. In the case of separated-flow transition, it was found that the length of a separation bubble prior to turbulent reattachment was a simple function of the local momentum thickness at separation and the overall surface length traversed by a fluid element prior to separation. Both the attached- and separated-flow transition models were implemented into the design system as point-like trips.

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Cumpsty, N. A., and J. H. Horlock. "Averaging Nonuniform Flow for a Purpose." Journal of Turbomachinery 128, no. 1 (February 1, 2005): 120–29. http://dx.doi.org/10.1115/1.2098807.

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Averaging nonuniform flow is important for the analysis of measurements in turbomachinery and gas turbines; more recently an important need for averaging arises with results of computational fluid dynamics (CFD). In this paper we show that there is a method for averaging which is “correct,” in the sense of preserving the essential features of the nonuniform flow, but that the type of averaging which is appropriate depends on the application considered. The crucial feature is the decision to retain or conserve those quantities which are most important in the case considered. Examples are given to demonstrate the appropriate methods to average nonuniform flows in the accounting for turbomachinery blade row performance, production of thrust in a nozzle, and mass flow capacity in a choked turbine. It is also shown that the numerical differences for different types of averaging are, in many cases, remarkably small.

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Barsi, Dario, Marina Ubaldi, Pietro Zunino, and Robert Fink. "A new compact hydraulic propeller turbine for low heads." E3S Web of Conferences 116 (2019): 00005. http://dx.doi.org/10.1051/e3sconf/201911600005.

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In this paper, a design procedure for a compact hydraulic propeller turbine for low heads is proposed and developed. The design is based upon classical criteria and on the employment of statistical correlations, which relates the main geometrical parameters to the fundamental design parameters of turbomachinery. The procedure for obtaining the meridional flow path and the stator vanes and rotor blades geometries is explained step by step. The obtained 3D model is employed to carry out a CFD calculation in order to obtain the turbine overall performance and main working parameters.

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Mangani, L., M. Darwish, and F. Moukalled. "An OpenFOAM pressure-based coupled CFD solver for turbulent and compressible flows in turbomachinery applications." Numerical Heat Transfer, Part B: Fundamentals 69, no. 5 (May 2, 2016): 413–31. http://dx.doi.org/10.1080/10407790.2015.1125212.

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Silva, E. Raimunda da, R. G. R. Camacho, and N. M. Filho. "Global optimization based on metamodel construction app lied to design axial turbomachinery cascades using CFD." IOP Conference Series: Earth and Environmental Science 12 (August 1, 2010): 012095. http://dx.doi.org/10.1088/1755-1315/12/1/012095.

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Holaind, Norman, Giuseppe Bianchi, Maxence De Miol, Samira Sayad Saravi, Savvas A. Tassou, Arthur Leroux, and Hussam Jouhara. "Design of radial turbomachinery for supercritical CO 2 systems using theoretical and numerical CFD methodologies." Energy Procedia 123 (September 2017): 313–20. http://dx.doi.org/10.1016/j.egypro.2017.07.256.

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42

Athavale, M. M., and R. C. Hendricks. "A Small Perturbation CFD Method for Calculation of Seal Rotordynamic Coefficients." International Journal of Rotating Machinery 2, no. 3 (1996): 167–77. http://dx.doi.org/10.1155/s1023621x96000048.

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Seal rotordynamic coefficients link the fluid reaction forces to the rotor motion, and hence are needed in the stability calculations for the overall rotating systems. Presented in this paper is a numerical method for calculations of rotordynamic coefficients of turbomachinery seals with rotors nominally at centered, eccentric and/or misaligned position. The rotor of the seal is assumed to undergo a prescribed small whirling motion about its nominal position. The resulting flow variable perturbations are expressed as Fourier functions in time. The N-S equations are used to generate the governing equations for the perturbation variables. Use of complex variables for the perturbations renders the problem quasi-steady. The fluid reaction forces are integrated on the rotor surface to obtain the fluid reaction forces at several different whirl frequencies. The rotordynamic coefficients are calculated using appropriate curve fitting. Details of the model are presented, and sample results for concentric and eccentric annular incompressible flow seals are included to demonstrate the capability and accuracy of the proposed method.

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Zhou, Ling, Ling Bai, Wei Li, Weidong Shi, and Chuan Wang. "PIV validation of different turbulence models used for numerical simulation of a centrifugal pump diffuser." Engineering Computations 35, no. 1 (March 5, 2018): 2–17. http://dx.doi.org/10.1108/ec-07-2016-0251.

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Purpose The purpose of this study is to validate the different turbulence models using in the numerical simulation of centrifugal pump diffuser. Computational fluid dynamics (CFD) has become the main method to study the pump inner flow patterns. It is important to understand the differences and features of the different turbulence models used in turbomachinery. Design/methodology/approach The velocity flow fields in a compact return diffuser under different flow conditions are studied and compared between CFD and particle image velocimetry (PIV) measurements. Three turbulence models are used to solve the steady flow field using high-quality fine structured grids, including shear stress transport (SST) k-w model, detached-eddy simulation (DES) model and SST k-w model with low-Re corrections. Findings SST k-w model with low-Re correction gives better results compared to DES and SST k-w model, and gives a good predication about the vortex core position under strong part-loading conditions. Originality/value A special test rig is designed to carry out the 2D PIV measurements under high rotating speed of 2850 r/min, and the PIV results are used to validate the CFD results.

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Holley, Brian M., Sandor Becz, and Lee S. Langston. "Measurement and Calculation of Turbine Cascade Endwall Pressure and Shear Stress." Journal of Turbomachinery 128, no. 2 (February 1, 2005): 232–39. http://dx.doi.org/10.1115/1.2137744.

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The complex three-dimensional fluid flow on the endwall in an axial flow turbine blade or vane passage has been extensively investigated and reported on in turbomachinery literature. The aerodynamic loss producing mechanisms associated with the endwall flow are still not fully understood or quantitatively predictable. To better quantify wall friction contributions to endwall aerodynamic loss, low Mach number wind tunnel measurement of skin friction coefficients have been made on one endwall of a large scale cascade of high pressure turbine airfoils, at engine operating Reynolds numbers. Concurrently, predictive calculations of the endwall flow shear stress have been made using a computational fluid dynamics (CFD) code. Use of the oil film interferometry skin friction technique is described and applied to the endwall, to measure local skin friction coefficients and shear stress directions on the endwall. These are correlated with previously reported measured local endwall pressure gradients. The experimental results are discussed and compared to the CFD calculations, to answer questions concerning endwall aerodynamic loss predictive ability.

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Langtry, R. B., F. R. Menter, S. R. Likki, Y. B. Suzen, P. G. Huang, and S. Völker. "A Correlation-Based Transition Model Using Local Variables—Part II: Test Cases and Industrial Applications." Journal of Turbomachinery 128, no. 3 (March 1, 2004): 423–34. http://dx.doi.org/10.1115/1.2184353.

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A new correlation-based transition model has been developed, which is built strictly on local variables. As a result, the transition model is compatible with modern computational fluid dynamics (CFD) methods using unstructured grids and massive parallel execution. The model is based on two transport equations, one for the intermittency and one for the transition onset criteria in terms of momentum thickness Reynolds number. The proposed transport equations do not attempt to model the physics of the transition process (unlike, e.g., turbulence models), but form a framework for the implementation of correlation-based models into general-purpose CFD methods. Part I of this paper (Menter, F. R., Langtry, R. B., Likki, S. R., Suzen, Y. B., Huang, P. G., and Völker, S., 2006, ASME J. Turbomach., 128(3), pp. 413–422) gives a detailed description of the mathematical formulation of the model and some of the basic test cases used for model validation. Part II (this part) details a significant number of test cases that have been used to validate the transition model for turbomachinery and aerodynamic applications, including the drag crisis of a cylinder, separation-induced transition on a circular leading edge, and natural transition on a wind turbine airfoil. Turbomachinery test cases include a highly loaded compressor cascade, a low-pressure turbine blade, a transonic turbine guide vane, a 3D annular compressor cascade, and unsteady transition due to wake impingement. In addition, predictions are shown for an actual industrial application, namely, a GE low-pressure turbine vane. In all cases, good agreement with the experiments could be achieved and the authors believe that the current model is a significant step forward in engineering transition modeling.

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Moore, J. Jeffrey. "Three-Dimensional CFD Rotordynamic Analysis of Gas Labyrinth Seals." Journal of Vibration and Acoustics 125, no. 4 (October 1, 2003): 427–33. http://dx.doi.org/10.1115/1.1615248.

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Labyrinth seals are utilized inside turbomachinery to provide noncontacting control of internal leakage. These seals can also play an important role in determining the rotordynamic stability of the machine. Traditional labyrinth seal models are based on bulk-flow assumptions where the fluid is assumed to behave as a rigid body affected by shear stress at the interfaces. To model the labyrinth seal cavity, a single, driven vortex is assumed and relationships for the shear stress and divergence angle of the through flow jet are developed. These models, while efficient to compute, typically show poor prediction for seals with small clearances, high running speed, and high pressure.* In an effort to improve the prediction of these components, this work utilizes three-dimensional computational fluid dynamics (CFD) to model the labyrinth seal flow path by solving the Reynolds Averaged Navier Stokes equations. Unlike bulk-flow techniques, CFD makes no fundamental assumptions on geometry, shear stress at the walls, as well as internal flow structure. The method allows modeling of any arbitrarily shaped domain including stepped and interlocking labyrinths with straight or angled teeth. When only leakage prediction is required, an axisymmetric model is created. To calculate rotordynamic forces, a full 3D, eccentric model is solved. The results demonstrate improved leakage and rotordynamic prediction over bulk-flow approaches compared to experimental measurements.

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Mori, Masaaki. "Wake-body interaction Noise Simulations by Coupling CFD and BEM." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 263, no. 1 (August 1, 2021): 5360–71. http://dx.doi.org/10.3397/in-2021-3067.

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In many engineering applications, the wake-body interaction or body-vortex interaction (BVI) occurs. In the wake-body interaction, vortices shed from an upstream obstacle interact with downstream obstacle and generate noise, for example blades in a turbomachinery, tubes in a heat exchanger, rotating blades like a helicopter and wind turbine and so on. The rod-airfoil and airfoil-airfoil configurations are typical models for the wake-body interaction. A rod and an airfoil are immersed upstream of the airfoil. In this paper, we reviewed the noise mechanism generated by the wake-body interaction and show the numerical results obtained by the coupling method using commercial CFD and acoustic BEM codes. The results shows that depending on the spacing between the rod or airfoil and the airfoil, the flow patterns and noise radiation vary. With small spacing, the vortex shedding from the upstream obstacle is suppressed and it results in the suppression of the sound generation. With large spacing, the shear layer or the vortices shed from the upstream obstacle impinge on the downstream obstacle and it results in the large sound generation. The dominant peak frequency of the generated sound varies with increasing of the spacing between the two obstacles.

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Hildebrandt, Manuel, Corina Schwitzke, and Hans-Jörg Bauer. "Analysis of Heat Flux Distribution during Brush Seal Rubbing Using CFD with Porous Media Approach." Energies 14, no. 7 (March 29, 2021): 1888. http://dx.doi.org/10.3390/en14071888.

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This paper discusses the question of heat flux distribution between bristle package and rotor during a rubbing event. A three-dimensional Computational Fluid Dynamics (3D CFD) model of the brush seal test rig installed at the Institute of Thermal Turbomachinery (ITS) was created. The bristle package is modelled as a porous medium with local non-thermal equilibrium. The model is used to numerically recalculate experimentally conducted rub tests on the ITS test rig. The experimentally determined total frictional power loss serves as an input parameter to the numerical calculation. By means of statistical evaluation methods, the ma in influences on the heat flux distribution and the maximum temperature in the frictional contact are determined. The heat conductivity of the rotor material, the heat transfer coefficients at the bristles and the rubbing surface were identified as the dominant factors.

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Alawadhi, Khaled, Yousef Alhouli, Ali Ashour, and Abdullah Alfalah. "Design and Optimization of a Radial Turbine to Be Used in a Rankine Cycle Operating with an OTEC System." Journal of Marine Science and Engineering 8, no. 11 (October 29, 2020): 855. http://dx.doi.org/10.3390/jmse8110855.

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Design and optimization of a radial turbine for a Rankine cycle were accomplished ensuring higher thermal efficiency of the system despite the low turbine inlet temperature. A turbine design code (TDC) based on the meanline design methodology was developed to construct the base design of the turbine rotor. Best design practices for the base design were discussed and adopted to initiate a robust optimization procedure. The baseline design was optimized using the response surface methodology and by coupling it with the genetic algorithm. The design variables considered for the study are rotational speed, total to static speed ratio, hub radius ratio, shroud radius ration, and number of blades. Various designs of the turbine were constructed based on the Central Composite Design (CCD) while performance variables were computed using the in-house turbine design code (TDC) in the MATLAB environment. The TDC can access the properties of the working fluid through a subroutine that links NIST’s REFPROP to the design code through a subroutine. The finalization of the geometry was made through an iterative process between 3D-Reynolds-Averaged Navier-Stokes (RANS) simulations and the one-dimensional optimization procedure. 3D RANS simulations were also conducted to analyze the optimized geometry of the turbine rotor for off-design conditions. For computational fluid dynamics (CFD) simulation, a commercial code ANSYS-CFX was employed. 3D geometry was constructed using ASYS Bladegen while structured mesh was generated using ANSYS Turbogrid. Fluid properties were supplied to the CFD solver through a real gas property (RGP) file that was constructed in MATLAB by linking it to REFPROP. Computed results show that an initial good design can reduce the time and computational efforts necessary to reach an optimal design successfully. Furthermore, it can be inferred from the CFD calculation that Response Surface Methodology (RSM) employing CFD as a model evaluation tool can be highly effective for the design and optimization of turbomachinery.

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Moore, J. J., and A. B. Palazzolo. "Rotordynamic Force Prediction of Whirling Centrifugal Impeller Shroud Passages Using Computational Fluid Dynamic Techniques." Journal of Engineering for Gas Turbines and Power 123, no. 4 (March 1, 1999): 910–18. http://dx.doi.org/10.1115/1.1385829.

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The demand for higher efficiencies and performance of modern centrifugal turbomachinery requires improved knowledge of critical design factors in strength of materials, aerodynamics, and rotordynamics. While tremendous strides in finite element stress analysis and computational fluid dynamics (CFD) have addressed the first two areas, the lack of accurate prediction tools for centrifugal impellers typically leaves rotordynamics out of the design loop. While several authors have analyzed the rotordynamic forces arising from shrouded centrifugal impellers, there has been no study to couple the secondary shroud passage with the three-dimensional primary flow model. The strong interaction between these domains makes this approach advantageous. The current study utilizes CFD techniques to analyze the full three-dimensional viscous, primary/secondary flow field in a centrifugal pump impeller to determine rotordynamic forces. Multiple quasi-steady solutions of an eccentric three-dimensional model at different precessional frequency ratios yield the rotordynamic impedance forces. Performing a second-order least-squares analysis generates the skew-symmetric stiffness, damping, and mass matrices. The results show good correlation with experiment for both performance and rotordynamic forces.

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Journal articles on the topic 'Turbomachinery; CFD'

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