Turbine Stator Well CFD Studies: Effects of Coolant Supply Geometry on Cavity Sealing Performance

Andreini, Antonio; Soghe, Riccardo Da; Facchini, Bruno

doi:10.1115/1.4000570

Cited by 10 publications

(3 citation statements)

References 17 publications

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“…As the number of purge holes decreased, jet momentum increased and the purge flow spread throughout the rim cavity leading to more effective rotor disk cooling. A companion computational fluid dynamics (CFD) study by Andreini et al [12] showed that the cavity flow dynamics differed with purge air delivery angles and purge hole locations. Both the axial and tangential purge flow momentum was shown to affect the cavity sealing effectiveness.…”

Section: Review Of Literaturementioning

confidence: 99%

Effects of Purge Jet Momentum on Sealing Effectiveness

Clark

Barringer

Thole

et al. 2016

Journal of Engineering for Gas Turbines and Power

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Driven by the need for higher cycle efficiencies, overall pressure ratios for gas turbine engines continue to be pushed higher thereby resulting in increasing gas temperatures. Secondary air, bled from the compressor, is used to cool turbine components and seal the cavities between stages from the hot main gas path. This paper compares a range of purge flows and two different purge hole configurations for introducing the purge flow into the rim cavities. In addition, the mate face gap leakage between vanes is investigated. For this particular study, stationary vanes at engine-relevant Mach and Reynolds numbers were used with a static rim seal and rim cavity to remove rotational effects and isolate gas path effects. Sealing effectiveness measurements, deduced from the use of CO2 as a flow tracer, indicate that the effectiveness levels on the stator and rotor side of the cavity depend on the mass and momentum flux ratios of the purge jets relative to the swirl velocity. For a given purge flow rate, fewer purge holes resulted in better sealing than the case with a larger number of holes.

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Section: Review Of Literaturementioning

confidence: 99%

Effects of Purge Jet Momentum on Sealing Effectiveness

Clark

Barringer

Thole

et al. 2016

Journal of Engineering for Gas Turbines and Power

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show abstract

“…This entrainment phenomenon increased the effectiveness by as much as 50% as a direct result of the purge flow delivery system. Companion numerical studies by Andreini et al [13] showed that increasing the momentum of the purge flow affected the robustness of the purge flow delivery.…”

Section: Introductionmentioning

confidence: 99%

Effects of Purge Flow Configuration on Sealing Effectiveness in a Rotor–Stator Cavity

Clark

Barringer

Johnson

et al. 2018

Journal of Engineering for Gas Turbines and Power

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Secondary air is bled from the compressor in a gas turbine engine to cool turbine components and seal the cavities between stages. Unsealed cavities can lead to hot gas ingestion, which can degrade critical components or, in extreme cases, can be catastrophic to engines. For this study, a 1.5 stage turbine with an engine-realistic rim seal was operated at an engine-relevant axial Reynolds number, rotational Reynolds number, and Mach number. Purge flow was introduced into the interstage cavity through distinct purge holes for two different configurations. This paper compares the two configurations over a range of purge flow rates. Sealing effectiveness measurements, deduced from the use of CO2 as a flow tracer, indicated that the sealing characteristics were improved by increasing the number of uniformly distributed purge holes and improved by increasing levels of purge flow. For the larger number of purge holes, a fully sealed cavity was possible, while for the smaller number of purge holes, a fully sealed cavity was not possible. For this representative cavity model, sealing effectiveness measurements were compared with a well-accepted orifice model derived from simplified cavity models. Sealing effectiveness levels at some locations within the cavity were well-predicted by the orifice model, but due to the complexity of the realistic rim seal and the purge flow delivery, the effectiveness levels at other locations were not well-predicted.

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“…There is a two-fold impact: a reduction in bypass losses (therefore increasing useful work) and an increase in cavity swirl, thereby reducing shear stress and windage. Experiments and computations have shown that the location, geometry, and angle of the superposed flows strongly influence the sealing characteristics [6][7][8].…”

Section: Introduction and Review Of Relevant Researchmentioning

confidence: 99%

Windage Torque Reduction in Low-Pressure Turbine Cavities Part II: Experimental and Numerical Results

Jackson,

Li,

Christodoulou

et al. 2024

Journal of Turbomachinery

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Minimizing the losses within a low-pressure turbine (LPT) system is critical for the design of next-generation ultra-high bypass ratio aero-engines. The stator-well cavity windage torque can be a significant source of loss within the system, influenced by the ingestion of mainstream annulus air with a tangential velocity opposite to that of the rotor. This paper presents experimental and numerical results of three carefully designed Flow Control Concepts (FCCs) – additional geometric features on the stator surfaces, which were optimized to minimize the windage torque within a scaled, engine-representative stator-well cavity. FCC1 and FCC2 featured rows of guide vanes at the inlet to the downstream and upstream wheel-spaces, respectively. FCC3 combined FCC1 and FCC2. Superposed flows were introduced to the upstream section of the cavity, which modelled the low radius coolant and higher radius leakage between the rotor blades. In addition to torque measurements, total and static pressures were collected, from which the cavity swirl ratio was derived. Additional swirl measurements were collected using a five-hole aerodynamic probe, which traversed radially at the entrance and exit of the cavity. A cavity windage torque reduction of 55% on the baseline (which has no flow control) was measured for FCC3, at the design condition with superposed flow. For this concept, an increase in the cavity swirl in both the upstream and downstream wheel-spaces was demonstrated experimentally and numerically. With increasing superposed flow, the contribution of FCC1 surpassed FCC2, due to more mass flow entering

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Turbine Stator Well CFD Studies: Effects of Coolant Supply Geometry on Cavity Sealing Performance

Cited by 10 publications

References 17 publications

Effects of Purge Jet Momentum on Sealing Effectiveness

Effects of Purge Jet Momentum on Sealing Effectiveness

Effects of Purge Flow Configuration on Sealing Effectiveness in a Rotor–Stator Cavity

Windage Torque Reduction in Low-Pressure Turbine Cavities Part II: Experimental and Numerical Results

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