Simulations of Flow Ingestion and Related Structures in a Turbine Disk Cavity

Julien, Steve; Lefrancois, Julie; Dumas, Guy; Boutet-Blais, Guillaume; Lapointe, Simon; Caron, Jean‐François; Marini, Remo

doi:10.1115/gt2010-22729

Cited by 29 publications

(28 citation statements)

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“…Julien et al [46] reported a URANS study based on an industrial test rig geometry described by Feieriesen et al [47]. As shown in figure 5, a radial seal is combined with an outer chute region.…”

Section: Radial Rim Sealsmentioning

confidence: 99%

Flow mechanisms in axial turbine rim sealing

Chew

Gao

Palermo

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper presents a review of research on turbine rim sealing with emphasis placed on the underlying flow physics and modelling capability. Rim seal flows play a crucial role in controlling engine disc temperatures but represent a loss from the main engine power cycle and are associated with spoiling losses in the turbine. Elementary models that rely on empirical validation and are currently used in design do not account for some of the known flow mechanisms, and prediction of sealing performance with computational fluid dynamics (CFD) has proved challenging. CFD and experimental studies have indicated important unsteady flow effects that explain some of the differences identified in comparing predicted and measure sealing effectiveness. This review reveals some consistency of investigations across a range of configurations, with inertial waves in the rotating flow apparently interacting with other flow mechanisms which include vane, blade and seal flow interactions, disc pumping and cavity flows, shear layer and other instabilities, and turbulent mixing.

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Section: Radial Rim Sealsmentioning

confidence: 99%

Flow mechanisms in axial turbine rim sealing

Chew

Gao

Palermo

2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…This is believed to be due to the appearance and importance of large-scale rotating structures within the wheel-space that cannot be captured correctly due to the constraints imposed by the single-sector (1 : 1) modelling approximation. If È o is sufficiently large, these rotating structures are suppressed; Julien et al 13 and Dunn et al 14 made similar observations.…”

Section: Axial Clearance Sealmentioning

confidence: 62%

“…These effects were found to be inhibited by increasing the sealing flow rate. These points are supported by more recent unsteady computations by Julien et al 13 and Dunn et al 14 O'Mahoney et al 15 used unsteady Reynolds-averaged Navier-Stokes (URANS) computations and large eddy simulation (LES) to study rim seal ingress for a chute-seal geometry. They compared computational results to experimental data and found that the LES results gave better agreement in terms of sealing effectiveness.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 82%

Computational extrapolation of turbine sealing effectiveness from test rig to engine conditions

Teuber

Maltson

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part A:

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The commercial computational fluid dynamics code ANSYS CFX 12.1 has been employed to carry out unsteady Reynolds-averaged Navier-Stokes computations to investigate the fluid mechanics of two different rim-seal geometries in a three-dimensional model of a turbine stage. The mainstream annulus, seal and wheel-space geometries are based on an experimental test rig used at the University of Bath. The calculated peak-to-trough pressure difference in the annulus, which is the main driving mechanism for ingestion, is in good agreement with experimental measurements. There is also a good agreement between the computed and measured swirl ratios in the wheel-space. Computed values of concentration-based sealing effectiveness are obtained over a range of sealing flow rates for both an axial clearance and a radial clearance rim seal. A good agreement with gas concentration measurements is found for the axial clearance seal over a certain range of sealing flow rates. Some under-prediction of the amount of ingestion for the radial clearance seal is obtained. The computed mainstream pressure coefficient increases progressively with mainstream Mach number in moving from quasi-incompressible experimental rig conditions to the compressible flow conditions encountered in engines. It is shown that the minimum sealing flow rate required to prevent ingestion increases as mainstream Mach number increases. A scaling method is proposed to allow sealing flow rates to prevent ingestion obtained from low Mach number experiments to be extrapolated to engine-representative conditions.

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“…A computational study performed by Julien et al [8] includes a sector model of a model with 44 inlet guide vanes and 58 rotor blades. The model shows about 30 structures within the rim seal cavity; they are moving at 90% of the rotor speed.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Flow Structures within a Turbine Rim Seal Cavity in the Presence of Purge Flow—An Experimental and Computational Unsteady Aerodynamics Investigation

2019

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Flow within the space between the rotor and stator of a turbine disk, and an area referred to as the rim seal cavity, develops azimuthal velocity component from the rotor disk. The fluid within develops unsteady structures that move at a fraction of the rotor speed. A test is designed to measure the number of unsteady structures and the rotational speed at which they are moving in the rim seal cavity of an experimental research rig. Data manipulation was developed to extract the speed, and the numbers of structures present using two fast-response aerodynamic probes measuring static pressure on the surface of the nozzle guide vane (NGV)-side rim seal cavity. A computational study is done to compare measured results to a transient unsteady Reynolds-averaged Navier–Stokes (URANS). The computational simulation consists of eight vanes and ten blades, carefully picked to reduce the error caused by blade vane pitch mismatch and to allow for the structures to develop correctly, and the rim seal cavity to measure the speed and number of the structures. The experimental results found 15 structures moving at 77.5% of the rotor speed, and the computational study suggested 14.5 structures are moving at 81.7% rotor speed. The agreement represents the first known test of its kind in a large-scale turbine test rig and the first known “good” agreement between computational and experimental work.

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Simulations of Flow Ingestion and Related Structures in a Turbine Disk Cavity

Cited by 29 publications

References 0 publications

Flow mechanisms in axial turbine rim sealing

Flow mechanisms in axial turbine rim sealing

Computational extrapolation of turbine sealing effectiveness from test rig to engine conditions

Unsteady Flow Structures within a Turbine Rim Seal Cavity in the Presence of Purge Flow—An Experimental and Computational Unsteady Aerodynamics Investigation

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