Abstract
Rotor-stator cavities are frequently encountered in engineering applications such as gas turbine engines. They are usually subject to an external hot mainstream crossflow which in general is highly swirled under the effect of the nozzle guide vanes. To avoid hot mainstream gas ingress, the cavity is usually purged by a stream of sealing flow. The interactions between the external crossflow, cavity flow, and sealing flow are complicated and involve all scales of turbulent unsteadiness and flow instability which are beyond the resolution of the Reynolds-average approach. To cope with such a complex issue, a wall-modeled large-eddy simulation (WMLES) approach is adopted in this study. In the simulation, a 20° sector model is used and subjected to a uniform pre-swirled external crossflow and a stream of radial sealing flow. It is triggered by a convergent Reynolds-averaged Navier-Stokes (RANS) result in which the shear stress transport (SST) turbulent model is used. In the WMLES simulation, the Smagoringsky sub-grid scale (SGS) model is applied. A scalar transportation equation is solved to simulate the blending and transportation process in the cavity. The overall flow field characteristics and deviation between RANS and WMLES results are discussed first. Both RANS and WMLES results show a Batchelor flow mode, while distinct deviation is also observed. Deviations in the small-radius region are caused by the insufficiency of the RANS approach in capturing the small-scale vortex structures in the boundary layer while deviations in the large-radius region are caused by the insufficiency of the RANS approach in predicting the external crossflow ingestion. The boundary layer vortex and external ingestion are then discussed in detail, highlighting the related flow instabilities. Finally, the large-flow structures induced by external flow ingress are analyzed using unsteady pressure oscillation signals.
目的
目的
本文旨在探究带有均匀预旋速度的外部横流对转静系盘腔流动特性的影响, 从而指导对真实发动机条件下涡轮盘腔流动特性的研究。
创新点
1. 采用壁面函数大涡模拟(WMLES)方法, 获得了带有横流通道的转静系盘腔更为精细的流场结构;2. 识别了盘腔轮缘处的开尔文-赫姆霍茨(K-H)不稳定性, 并探究了K-H剪切涡结构对轮缘处流动特性的影响。
方法
1. 通过高精度大涡模拟方法, 捕捉流场中的精细化流场结构。2. 结合理论推导, 通过对于流动结构的机理和动力学分析, 探究外部横流和盘腔耦合流动特性。
结论
1. 由于雷诺**均(RANS)模拟对壁面小尺度涡结构和输运方程的解析能力不足, 所以RANS模拟流场与WMLES模拟流场出现了明显偏差。2. 在横流和盘腔流动的耦合作用下, 由于轮缘处的速度剪切诱导产生K-H涡结构, 所以这些涡结构将会加**轮缘处的外部入侵和盘腔出流流动。3. 在外部入侵和盘腔出流的影响下, 盘腔端区发现了大尺度流动结构;这些大尺度流动结构以一定的转速旋转, 且其转速和数量可以通过快速傅里叶变换以及相关性分析确定。
Similar content being viewed by others
References
Bayley FJ, Owen J, 1970. The fluid dynamics of a shrouded disk system with a radial outflow of coolant. Journal of Engineering for Gas Turbines and Power, 92(3):335–341. https://doi.org/10.1115/1.3445358
Bhavnani SH, Khilnani VI, Tsai LC, et al., 1992. Effective sealing of a disk cavity using a double-toothed rim seal. Proceedings of the ASME International Gas Turbine and Aeroengine Congress and Exposition, No. V001T01A127. https://doi.org/10.1115/92-GT-379
Childs PRN, 2011. Chapter 7: rotating cavities. In: Childs PRN (Ed.), Rotating Flow. Butterworth-Heinemann, Oxford, UK, p.249–298. https://doi.org/10.1016/B978-0-12-382098-3.00007-X
Gao F, Chew JW, 2021. Evaluation and application of advanced CFD models for rotating disc flows. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 235(23):6847–6864. https://doi.org/10.1177/09544062211013850
Gao F, Chew JW, Marxen O, 2020. Inertial waves in turbine rim seal flows. Physical Review Fluids, 5(2):024802. https://doi.org/10.1103/PhysRevFluids.5.024802
Georgiadis NJ, Rizzetta DP, Fureby C, 2010. Large-eddy simulation: current capabilities, recommended practices, and future research. AIAA Journal, 48(8):1772–1784. https://doi.org/10.2514/1.J050232
Horwood JTM, Hualca FP, Scobie JA, et al., 2019. Experimental and computational investigation of flow instabilities in turbine rim seals. Journal of Engineering for Gas Turbines and Power, 141(1):011028. https://doi.org/10.1115/1.4041115
Hualca-Tigsilema FP, 2020. An Experimental Study of Ingress Through Gas-Turbine Rim Seals. PhD Thesis, University of Bath, Bath, UK.
Jakoby R, Zierer T, Lindblad K, et al., 2004. Numerical simulation of the unsteady flow field in an axial gas turbine rim seal configuration. ASME Turbo Expo 2004: Power for Land, Sea, and Air, p.431–440. https://doi.org/10.1115/GT2004-53829
Larsson J, Kawai S, Bodart J, et al., 2016. Large eddy simulation with modeled wall-stress: recent progress and future directions. Mechanical Engineering Reviews, 3(1):1500418. https://doi.org/10.1299/mer.15-00418
Lingwood RJ, 1995. Absolute instability of the boundary layer on a rotating disk. Journal of Fluid Mechanics, 299: 17–33. https://doi.org/10.1017/S0022112095003405
Nakhchi ME, Naung SW, Rahmati M, 2022. Influence of blade vibrations on aerodynamic performance of axial compressor in gas turbine: direct numerical simulation. Energy, 242:122988. https://doi.org/10.1016/j.energy.2021.122988
Naung SW, Nakhchi ME, Rahmati M, 2021. Prediction of flutter effects on transient flow structure and aeroelasticity of low-pressure turbine cascade using direct numerical simulations. Aerospace Science and Technology, 119: 107151. https://doi.org/10.1016/j.ast.2021.107151
O’Mahoney TSD, Hills NJ, Chew JW, et al., 2011. Large-eddy simulation of rim seal ingestion. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 225(12):2881–2891. https://doi.org/10.1177/0954406211409285
Owen JM, 2011a. Prediction of ingestion through turbine rim seals—part I: rotationally induced ingress. Journal of Turbomachinery, 133(3):031005. https://doi.org/10.1115/1.4001177
Owen JM, 2011b. Prediction of ingestion through turbine rim seals—part II: externally induced and combined ingress. Journal of Turbomachinery, 133(3):031006. https://doi.org/10.1115/1.4001178
Owen JM, Zhou KY, Pountney O, et al., 2012a. Prediction of ingress through turbine rim seals—part I: externally induced ingress. Journal of Turbomachinery, 134(3):031012. https://doi.org/10.1115/1.4003070
Owen JM, Pountney O, Lock G, 2012b. Prediction of ingress through turbine rim seals—part II: combined ingress. Journal of Turbomachinery, 134(3):031013. https://doi.org/10.1115/1.4003071
Palermo DM, Gao F, Amirante D, et al., 2020. Wall-modelled large eddy simulations of axial turbine rim sealing. ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition, No. V07CT14A015. https://doi.org/10.1115/GT2020-14973
Phadke UP, Owen JM, 1988a. Aerodynamic aspects of the sealing of gas-turbine rotor-stator systems: part 1: the behavior of simple shrouded rotating-disk systems in a quiescent environment. International Journal of Heat and Fluid Flow, 9(2):98–105. https://doi.org/10.1016/0142-727X(88)90060-4
Phadke UP, Owen JM, 1988b. Aerodynamic aspects of the sealing of gas-turbine rotor-stator systems: part 2: the performance of simple seals in a quasi-axisymmetric external flow. International Journal of Heat and Fluid Flow, 9(2):106–112. https://doi.org/10.1016/0142-727X(88)90061-6
Phadke UP, Owen JM, 1988c. Aerodynamic aspects of the sealing of gas-turbine rotor-stator systems: part 3: the effect of nonaxisymmetric external flow on seal performance. International Journal of Heat and Fluid Flow, 9(2): 113–117. https://doi.org/10.1016/0142-727X(88)90062-8
Pogorelov A, Schneiders L, Meinke M, et al., 2018. An adaptive Cartesian mesh based method to simulate turbulent flows of multiple rotating surfaces. Flow, Turbulence and Combustion, 100(1):19–38. https://doi.org/10.1007/s10494-017-9827-9
Rabs M, Benra FK, Dohmen HJ, et al., 2009. Investigation of flow instabilities near the rim cavity of a 1.5 stage gas turbine. ASME Turbo Expo 2009: Power for Land, Sea, and Air, p.1263–1272. https://doi.org/10.1115/GT2009-59965
Royce R, 2015. The Jet Engine. 5th Edition. John Wiley & Sons Inc., Chichester, UK.
Sangan CM, 2011. Measurement of Ingress Through Gas Turbine Rim Seals. PhD Thesis, University of Bath, Bath, UK.
Sangan CM, Pountney OJ, Zhou KY, et al., 2013. Experimental measurements of ingestion through turbine rim seals—part I: externally induced ingress. Journal of Turbomachinery, 135(2):021012. https://doi.org/10.1115/1.4006609
Saric WS, 1994. Görtler vortices. Annual Review of Fluid Mechanics, 26:379–409. https://doi.org/10.1146/annurev.fl.26.010194.002115
Savov SS, Atkins NR, 2017. A rim seal ingress model based on turbulent transport. ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. https://doi.org/10.1115/GT2017-63531
Savov SS, Atkins NR, Uchida S, 2017. A comparison of single and double lip rim seal geometries. Journal of Engineering for Gas Turbines and Power, 139(11):112601. https://doi.org/10.1115/1.4037027
Scobie JA, 2014. An Experimental Study of Gas Turbine Rim Seals. PhD Thesis, University of Bath, Bath, UK.
Séverac É, Poncet S, Serre É, et al., 2007. Large eddy simulation and measurements of turbulent enclosed rotor-stator flows. Physics of Fluids, 19(8):085113. https://doi.org/10.1063/1.2759530
**e L, Du Q, Liu G, et al., 2021. Flow characteristics in turbine wheel space cavity. Energy Reports, 7:2262–2275. https://doi.org/10.1016/j.egyr.2021.04.014
Acknowledgments
This work is supported by the National Natural Science Foundation of China (No. 5212201273) and the National Science and Technology Major Project of China (No. J2019-III-0003). The CFX software and computation resource supplied by Bei**g Super Cloud Computing Center, China are acknowledged.
Author information
Authors and Affiliations
Contributions
Qiang DU designed the research. Guang LIU and Zengyan LIAN processed the corresponding data. Lei XIE wrote the first draft of the manuscript. Yaguang XIE helped to organize the manuscript. Lei XIE and Yifu LUO revised and edited the final version.
Corresponding author
Additional information
Conflict of interest
Lei XIE, Qiang DU, Guang LIU, Zengyan LIAN, Yaguang XIE, and Yifu LUO declare that they have no conflict of interest.
Rights and permissions
About this article
Cite this article
**e, L., Du, Q., Liu, G. et al. Investigation of flow characteristics in a rotor-stator cavity under crossflow using wall-modelled large-eddy simulation. J. Zhejiang Univ. Sci. A 24, 473–496 (2023). https://doi.org/10.1631/jzus.A2200565
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1631/jzus.A2200565
Key words
- Wall-modeled large-eddy simulation (WMLES)
- Rotor-stator cavity
- Flow instability
- Reynolds-averaged Navier-Stokes (RANS)