Interaction of Shroud Leakage Flow and Main Flow in a Three-Stage LP Turbine

Gier, Jochen; Stubert, Bertram; Brouillet, Bernard; Vito, Laurent de

doi:10.1115/gt2003-38025

Cited by 24 publications

(11 citation statements)

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“…The position and structure of these vortices depend on the cavity geometry. The influence of shrouded blades in turbine is also studied by Gier et al [8] and Adami et al [9]. All these presented studies shows that the shroud leakage effect must be taken into account in the numerical simulations.…”

Section: Introductionmentioning

confidence: 91%

Interaction of shrouded stator flow and main flow and its influence on performances of a three-stage high pressure compressor

Marty

Aupoix

2012

Proceedings of the Institution of Mechanical Engineers, Part A:

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The prediction of the complex flows within a turbomachinery remains a challenging issue for computational fluid dynamics (CFD). The real features of a turbomachinery must be taken into account in the simulation but they increase its complexity. One of these features is the leakage flow due to the axial gap between the fixed and rotating parts of the hub. This article focuses on this flow within the scope of a high-pressure compressor. The results are compared with experimental data obtained in the main flow path. The leakage flow is characterized by several vortices, especially near the hub and between the seal-teeth. It interacts with the main flow: the hub separation is quite wider while the casing one is reduced in comparison with the smooth case. In this article, the smooth case is related to the simulation without any shrouded stator cavity. The leakage flow influences strongly on compressor performances. Taking into account the leakage flow in the CFD improves the agreement between CFD and experimental values. Due to the vortex prediction, the influence of the turbulence modelling is also assessed. The explicit algebraic Reynolds stress model improves the flow prediction while the presently investigated differential Reynolds stress model predicts too wide hub corner separation which leads to high underestimation of compressor performances.

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Section: Introductionmentioning

confidence: 91%

Interaction of shrouded stator flow and main flow and its influence on performances of a three-stage high pressure compressor

Marty

Aupoix

2012

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…Because the incidence loss is small, no discussion is presented here. 23 Denton 9 proposed the equation of mass-averaged entropy mixing loss coefficient ξmix, as expressed in equation (4). On the basis of this equation, the calculation of mass-averaged entropy inlet cavity loss coefficient ξin and mass-averaged entropy leakage loss coefficient ξjet are expressed by equations (11) to (13) where s 0 and s 1 are the entropy increases at the inlet and outlet of the axial clearance between the upstream stator and rotor, respectively.…”

Section: Resultsmentioning

confidence: 99%

Effects of leakage vortex on aerodynamic performance and loss mechanism of steam turbine

Cao

Wang

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part A:

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To avoid friction, a clearance between the rotor blade tip and the cylinder is needed in a steam turbine. As a result, the leakage flow is formed under the pressure difference which mixes with the main flow and causes the mixing loss. So, a numerical calculation was conducted based on a high-pressure 1.5-stage steam turbine with the tip labyrinth seal. The leakage vortex system and the mixing progress at different tip clearances were analyzed. The related leakage losses were calculated. The results show that the leakage flow will lead to the steam deflecting at the rotor exit and cause incidence loss. Furthermore, in the downstream stator, the leakage flow near the suction side with high radial velocity causes the deflection of the outflow angles. The main influence region of leakage flow is distributed above 75% of blade height, whereas the most intense region is distributed at approximately 95% of blade height. It is found that the mixing loss is related to the size of the backflow vortex. The related leakage losses increase with tip clearance, in which the mixing loss is the major part and the mass-averaged entropy mixing loss coefficient is 7–11%.

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“…Gier et al. 17 analyzed the interaction in a three-stage low-pressure turbine based on numerical simulations compared to experimental data. In their study, the effect of windage and reduction of work extraction were taken into consideration, and the losses were related to five different mechanisms referred to as by-pass losses, mixing losses, windage losses, step losses, and subsequent row losses.…”

Section: Introductionmentioning

confidence: 99%

Aerodynamic impact of hub and shroud leakage flow on an axial turbine stage

Liu

Zou

2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper presents a study analyzing the aerodynamic effect and loss mechanism of hub and shroud leakage flow for an axial turbine stage. A series of computational fluid dynamics computations were performed to investigate the effect of various complexity of leakage configurations on the flow field. It is found that a non-linear relationship between different flow systems emerges in the vicinity of both the shroud and hub leakage flow exhibiting a deviation of flow direction and a radial shift of flow pattern, while the efficiency drop caused by the shroud and hub leakage configurations can be added linearly. By analyzing the expansion process in the cooled turbine and the spatial distribution of viscous dissipation term, the loss sources which can be directly traced back to the flow phenomena were indentified. Based on the aerodynamic feature of the turbine, an analytical approach to separate and quantify loss sources was proposed and applied to analyze the turbine. Four kinds of loss mechanisms, referred to as cavity losses, mixing losses, extra losses, and the leakage work reduction, were observed and their contributions were eventually represented by efficiency penalty.

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Interaction of Shroud Leakage Flow and Main Flow in a Three-Stage LP Turbine

Cited by 24 publications

References 0 publications

Interaction of shrouded stator flow and main flow and its influence on performances of a three-stage high pressure compressor

Interaction of shrouded stator flow and main flow and its influence on performances of a three-stage high pressure compressor

Effects of leakage vortex on aerodynamic performance and loss mechanism of steam turbine

Aerodynamic impact of hub and shroud leakage flow on an axial turbine stage

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