Large-Eddy Simulation of the Unsteady Full 3D Rim Seal Flow in a One-Stage Axial-Flow Turbine

Pogorelov, Alexej; Meinke, Matthias; Schröder, Wolfgang

doi:10.1007/s10494-018-9956-9

Cited by 23 publications

(15 citation statements)

References 57 publications

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“…Recent studies using LES have shown improved agreement with experimental measurements to those with RANS and URANS, in terms of pressure distribution and sealing effectiveness. These include studies by O'Mahoney et al [18,25], Gao et al [19] and Pogorelov et al [26]. This indicates that LES can give further insight into flow mechanisms in rim seals.…”

Section: Introductionmentioning

confidence: 90%

Inertial waves in turbine rim seal flows

2020

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Rotating fluids are well-known to be susceptible to waves. This has received much attention from the geophysics, oceanographic and atmospheric research communities. Inertial waves, which are driven by restoring forces, for example the Coriolis force, have been detected in the research fields mentioned above. This paper investigates inertial waves in turbine rim seal flows in turbomachinery. These are associated with the large-scale unsteady flow structures having distinct frequencies, unrelated to the main annulus blading, identified in many experimental and numerical studies. These unsteady flow structures have been shown in some cases to reduce sealing effectiveness and are difficult to predict with conventional steady Reynolds-averaged Navier-Stokes (RANS) approaches. Improved understanding of the underlying flow mechanisms and how these could be controlled is needed to improve the efficiency and stability of gas turbines. This study presents large-eddy simulations for three rim seal configurations-chute, axial and radial rim seals-representative of those used in gas turbines. Evidence of inertial waves is shown in the axial and chute seals, with characteristic wave frequencies limited within the threshold for inertial waves given by classic linear theory (i.e. |f * /f rel | ≤ 2), and instantaneous flow fields showing helical characteristics. The radial seal, which limits the radial fluid motion with the seal geometry, restricts the Coriolis force and suppresses the inertial wave.

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Section: Introductionmentioning

confidence: 90%

Inertial waves in turbine rim seal flows

2020

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“…The operating conditions are listed in Table 1. The data for CW2K is taken from (Pogorelov et al 2019). For both operating conditions, it takes approximately 40 full rotor rotations until the flow field is fully developed.…”

Section: Resultsmentioning

confidence: 99%

“…This study intends to increase the understanding of the inherent unsteady nature of the rim seal flow in axial flow turbines and follows the work of (Pogorelov et al 2019). They conducted high fidelity LES of an axial flow turbine for the full 360° circumference of the main flow and the wheel space such that the uncertainty of RANS turbulence modelling and the limitations of a sector model was avoided.…”

Section: Introductionmentioning

confidence: 99%

“…Adding a second sealing lip supressed these fluctuations and reduced the hot gas ingress. In this paper, new results for the double lip rim seal geometry investigated by (Pogorelov et al 2019) are presented for a cooling gas mass flow rate reduced by 50%.…”

Section: Introductionmentioning

confidence: 99%

“…Second, the computational setup, the investigated operating conditions, and boundary conditions are presented. Afterwards, the results of the flow field inside the rotor-stator wheel space are presented and compared to the results for the higher cooling gas mass flow rate from (Pogorelov et al 2019). Finally, some conclusions are drawn.…”

Section: Introductionmentioning

confidence: 99%

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Large-Eddy Simulations of Rim Seal Flow in a One-Stage Axial Turbine

Hösgen¹,

Meinke²,

Schröder³

2020

Proceedings of Global Power &Amp; Propulsion Society

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The flow field in a one-stage axial flow turbine with 30 stator and 62 rotor blades including the wheel space is investigated by large-eddy simulation (LES). The Navier-Stokes equations are solved using a massively parallel finite-volume solver based on a Cartesian mesh with immersed boundaries. The strict conservation of mass, momentum, and energy is ensured by an efficient cut-cell/level-set ansatz, where a separate level-set solver describes the motion of the rotor. Both solvers use individual subsets of a shared Cartesian mesh, which they can adapt independently. The focus of the analysis is on the flow field inside the rotor stator cavity between the stator and rotor disks. Two cooling gas mass flow rates are investigated for the same rim seal geometry. First, the time averaged flow field for both simulations is compared, followed by a detailed investigation of the unsteady flow field. The results for the cooling effectiveness are compared to experimental data. Both cases show good agreement with experimental data. It is shown that for the lower cooling gas mass flux several of the wheel space's acoustic waves are excited. This is not observed for the higher cooling gas mass flux. The excited waves lead to stable, i.e., bounded, fluctuations inside the wheel space and result in a significantly higher hot gas ingestion.

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Effects of Sealing Flow Supply Configuration with Holes on Sealing Effectiveness of Turbine Rim Seal

Gai

Zhu

et al. 2022

J. Therm. Sci.

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Large-Eddy Simulation of the Unsteady Full 3D Rim Seal Flow in a One-Stage Axial-Flow Turbine

Cited by 23 publications

References 57 publications

Inertial waves in turbine rim seal flows

Inertial waves in turbine rim seal flows

Large-Eddy Simulations of Rim Seal Flow in a One-Stage Axial Turbine

Effects of Sealing Flow Supply Configuration with Holes on Sealing Effectiveness of Turbine Rim Seal

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