Main Gas Ingestion in a Turbine Stage for Three Rim Cavity Configurations

Zhou, Daqing; Roy, R. P.; Wang, C.-Z.; Glahn, J. Axel

doi:10.1115/gt2009-59851

Cited by 15 publications

(11 citation statements)

References 0 publications

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“…Zhou et al [45] reported URANS solutions for a 14.4 o sector model with blades and vanes for a simple double seal configuration tested at Arizona State University [32]. Ingestion was shown to be underpredicted compared to measurements and the authors suggested that this may be due to rotating low pressure zones being supressed by the small sector periodicity.…”

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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“…Zhou et al [8] described experiments and computations for three wheel-space configurations having different aspect ratios. At low sealing rate, they also identified the regions of ingress and egress around the rim seal through PIV images of instantaneous velocity.…”

Section: Ihtc15-8457mentioning

confidence: 99%

Effects of Ingestion on the Flow and Heat Transfer in a Rotor-Stator System

Wang¹,

Wilson²

2014

Proceedings of the 15th International Heat Transfer Conference

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Ingestion (or ingress) of hot mainstream gas into the wheel-spaces between the rotor and stator discs in the high pressure stages of gas turbines is one of the most important internal cooling problems for engine designers. A rim seal at the periphery of the wheel-space and a radial outflow of sealing air are used to reduce or prevent this damaging ingestion. The sealing air is also used for rotor disc cooling. In this paper, a simplified axisymmetric computational fluid dynamics (CFD) model of a gas turbine rotor-stator wheel-space is used to predict the effects of ingress on the flow and heat transfer. The steady flow computations are carried out using the CFD code ANSYS/CFX and the shear stress transport (SST) turbulence model. The rotational Reynolds number, inlet flow rates and thermal boundary settings are selected to represent the operating conditions of an ingress experimental rig, and comparisons are made between computations and measurements of heat transfer in the wheel-space. The computed heat transfer from the steady model (in terms of values of local Nusselt number on the rotor) is in broad agreement with measurements obtained using thermochromic liquid crystal in a transient experiment. Alternative wall-surface thermal boundary conditions are investigated in order to study the sensitivity of computed Nusselt numbers to these modelling assumptions.

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“…Zhou et al 3 reviewed previous computational studies related to ingress, including those by Hills et al, 4 Laskowski et al, 5 Rabs et al, 6 Johnson et al, 7 Wang et al, 8 Zhou et al 9 and Mirzamoghadam et al 10,11 A number of authors have noted that the statistical convergence for pressure variations in the annulus is more quickly and more easily obtained than the cooling effectiveness field in the wheel-space.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

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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Main Gas Ingestion in a Turbine Stage for Three Rim Cavity Configurations

Cited by 15 publications

References 0 publications

Flow mechanisms in axial turbine rim sealing

Flow mechanisms in axial turbine rim sealing

Effects of Ingestion on the Flow and Heat Transfer in a Rotor-Stator System

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

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