An Experimental Investigation of a Gas Turbine Disk Cooling System

Volume 1: Turbomachinery

1994

Section: Introductionmentioning

confidence: 85%

Rim Sealing of Rotor-Stator Wheelspaces in the Presence of External Flow

Chew

Green

Volume 1: Turbomachinery

1994

“…For example, Abe et al (1979), Kobayashi et al (1984), Phadke and Owen (1988), Dadkhah et al (1991) and Hamabe and Ishida (1992) have performed experiments with various degrees of asymmetry in the annulus flow caused by guide vanes or other disturbances in the stationary reference frame. As suggested by Campbell, the presence of a circumferentially uniform external flow tends to improve sealing, while circumferential asymmetries tend to increase ingestion.…”

Section: Introductionmentioning

confidence: 99%

Computational and Mathematical Modeling of Turbine Rim Seal Ingestion

Hills

Chew

Journal of Turbomachinery

2002

Understanding and modelling of main annulus gas ingestion through turbine rim seals is considered and advanced in this paper. Unsteady 3-dimensional computational fluid dynamics (CFD) calculations and results from a more elementary model are presented and compared with experimental data previously published by Hills et al (1997). The most complete CFD model presented includes both stator and rotor in the main annulus and the inter-disc cavity. The k-ε model of turbulence with standard wall function approximations is assumed in the model which was constructed in a commercial CFD code employing a pressure correction solution algorithm. It is shown that considerable care is needed to ensure convergence of the CFD model to a periodic solution. Compared to previous models, results from the CFD model show encouraging agreement with pressure and gas concentration measurements. The annulus gas ingestion is shown to result from a combination of the stationary and rotating circumferential pressure asymmetries in the annulus. Inertial effects associated with the circumferential velocity component of the flow have an important effect on the degree of ingestion.The elementary model used is an extension of earlier models based on orifice theory applied locally around the rim seal circumference. The new model includes a term accounting for inertial effects. Some good qualitative and fair quantitative agreement with data is shown.

“…This was confirmed experimentally by several workers. For example Abe et al [2], Kobayashi et al [3], Phadke and Owen [4], Dadkhah et al [5], Hamabe and Ishida [6] and Chew et al [7] have performed experiments with various asymmetries in the annulus caused by guide vanes or other stationary disturbances. The conclusion may be drawn from these results that, at engine conditions, circumferential pressure asymmetries are the primary cause of ingestion.…”

Section: Introductionmentioning

confidence: 99%

Measurement and Analysis of Ingestion Through a Turbine Rim Seal

Gentilhomme

Hills

Journal of Turbomachinery

et al. 2003

Experimental measurements from a new single stage turbine are presented. The turbine has 26 vanes and 59 rotating blades with a design point stage expansion ratio of 2.5 and vane exit Mach number of 0.96. A variable sealing flow is supplied to the disc cavity upstream of the rotor and then enters the annulus through a simple axial clearance seal situated on the hub between the stator and rotor. Measurements at the annulus hub wall just downstream of the vanes show the degree of circumferential pressure variation. Further pressure measurements in the disc cavity indicate the strength of the swirling flow in the cavity, and show the effects of mainstream gas ingestion at low sealing flows. Ingestion is further quantified through seeding of the sealing air with nitrous oxide or carbon dioxide and measurement of gas concentrations in the cavity. Interpretation of the measurements is aided by steady and unsteady computational fluid dynamics solutions, and comparison with an elementary model of ingestion.