Numerical Study of the Ingestion Phenomenon in a Turbine Rim Seal

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Total Pages : 160 pages
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Book Synopsis Numerical Study of the Ingestion Phenomenon in a Turbine Rim Seal by : Guillaume Boutet-Blais

Download or read book Numerical Study of the Ingestion Phenomenon in a Turbine Rim Seal written by Guillaume Boutet-Blais and published by . This book was released on 2012 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce mémoire de maîtrise porte sur la modélisation numérique de la problématique d'ingestion de gaz chauds dans la cavité rotor-stator du premier étage d'une turbine à gaz moderne. Dans le contexte de développement d'une aviation plus écologique, ce sujet mérite une attention marquée car des gains importants en ce qui a trait à l'efficacité globale du moteur peuvent être atteints par de meilleurs designs de joints rotor-stator limitant l'ingestion. La modélisation physique des phénomènes affectant l'ingestion devient alors essentielle afin de développer une meilleure compréhension des écoulements et mécanismes en présence. C'est dans cette optique que Pratt & Whitney Canada a mandaté le Laboratoire de Mécanique des Fluides Numérique (LMFN) de l'Université Laval afin de conduire une étude approfondie du phénomène d'ingestion. Ce mémoire a donc pour objectif principal de décrire le développement, l'application et la validation de certaines techniques de simulation numérique visant à caractériser qualitativement et quantitativement le phénomène d'ingestion observé à travers le joint et dans la cavité du groupe rotor-stator d'une turbine à gaz. Une investigation des limites de fiabilité d'une telle modélisation numérique dans un contexte réel d'opération du moteur est également présentée. La paramétrisation adéquate du problème et la validité d'extrapoler des résultats numériques d'ingestion obtenus aux conditions "banc d'essai" afin de prédire l'ingestion réelle aux conditions "moteur" font également partie des sujets abordés dans ce mémoire. La méthodologie développée considère deux phases de calculs menant à des diagnostics d'ingestion par le biais d'un marqueur passif. Une série de validations numériques et des comparaisons avec des résultats expérimentaux sont également présentées. La méthodologie de modélisation numérique est considérée robuste et fiable, mais seulement partiellement validée.

Computational Assessment of Turbine Rim Seal System Parametric Variation on Hot Gas Ingestion and Flow Pattern

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Total Pages : 127 pages
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Book Synopsis Computational Assessment of Turbine Rim Seal System Parametric Variation on Hot Gas Ingestion and Flow Pattern by : Peter Joseph Rock (Jr.)

Download or read book Computational Assessment of Turbine Rim Seal System Parametric Variation on Hot Gas Ingestion and Flow Pattern written by Peter Joseph Rock (Jr.) and published by . This book was released on 2018 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: A design of experiments (DOE) is carried out to assess the turbine rim cavity system parametric variation on hot gas ingestion, flow pattern, and turbine stage efficiency. The parameters focused on are purge to main mass flow rate ratio, axial gap to rim radius ratio, radial gap to rim radius ratio, normalized axial position of the blade leading edge, and internal purge cavity radius ratios. The results were used to formulate a non-dimensional sealing parameter, [psi], that has a threshold value of [psi] = 2.3 - 1015, beyond which there is only a marginal variation in ingestion penetration depth. This non-dimensional sealing parameter is given as a function of rim seal geometry, purge mass flow rate ratio, Rotational Reynolds number, purge flow Reynolds number, rim seal Reynolds number, and Rossby number. The non-dimensional sealing parameter reflects the physical effects associated with rim seal geometry, flow characteristics, and operating parameters. The computed flow field demonstrates the dominant role of vortical structures in the rim cavity flow on effective flow area distribution and hence the ingestion penetration depth. Quantitative attributes of the vortex, such as non-dimensional circulation, maximum vorticity, height to width ratio, and normalized vortex center position, scale with the non-dimensional sealing parameter. As a result, the vortex attributes scale with ingestion penetration depth. The implication is that the sealing parameter potentially provides a guideline for selecting rim seal configurations and operating space to yield marginal levels of hot gas ingestion. The variation in turbine stage efficiency is approximately linear with purge mass flow rate ratio, where a decrease of 0.7% in efficiency is observed for every 1% increase in purge mass flow rate ratio. This result is in accord with published results to-date.

Rim Seal Experiments and Analysis for Turbine Applications

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Total Pages : 0 pages
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Book Synopsis Rim Seal Experiments and Analysis for Turbine Applications by : W. A. Daniels

Download or read book Rim Seal Experiments and Analysis for Turbine Applications written by W. A. Daniels and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted to determine the sealing effectiveness and the aerodynamic characteristics of four rim seal models for a number of flow conditions. The experiments were conducted to obtain an extended data base for advanced turbine rim seal design. The class of rim seals investigated are those found on the downstream side of the rotor where the boundary layer on the disk is pumped directly into the seal gap. The experiments were conducted at disk tangential Reynolds numbers up to 5.1 × 106 with a simulated gas path flow across the top of the seal. The simulated gas path flow was injected with various amounts of swirl to determine the effect of swirl on the seal effectiveness. The radial gap and the axial overlap of the seal were varied and results compared with a baseline configuration. A rim seal configuration intended to prevent disk pumping directly into the seal gap was also investigated. A mass transfer analogy was used to characterize the rim seal ingestion characteristics and the trace gas chosen for this technique was CO2. The results of this investigation indicate that decreasing the radial gap of the seal produces a better improvement in seal effectiveness than increasing the axial overlap of the seal, that seal effectiveness increases only modestly as the swirl across the top of the seal decreases, and that the trace gas technique employed to determine seal effectiveness is an accurate alternative to pressure measurement or flow visualization techniques used by other investigators. The results of this investigation were compared with results from a boundary layer model for rim seals with axial gap geometries.

Turbine Rim Seal Gas Path Flow Ingestion Mechanisms

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Total Pages : pages
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Book Synopsis Turbine Rim Seal Gas Path Flow Ingestion Mechanisms by : Bruce V. Johnson

Download or read book Turbine Rim Seal Gas Path Flow Ingestion Mechanisms written by Bruce V. Johnson and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Turbine Rim Seal Ingestion

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ISBN 13 :
Total Pages : 412 pages
Book Rating : 4.:/5 (847 download)

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Book Synopsis Turbine Rim Seal Ingestion by : O. J. P. Gentilhomme

Download or read book Turbine Rim Seal Ingestion written by O. J. P. Gentilhomme and published by . This book was released on 2004 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Ingestion and Sealing Performance of Rim Seals in Rotor-stator Wheelspaces

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Book Synopsis Ingestion and Sealing Performance of Rim Seals in Rotor-stator Wheelspaces by : S. Dadkhah

Download or read book Ingestion and Sealing Performance of Rim Seals in Rotor-stator Wheelspaces written by S. Dadkhah and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Turbine Rim Seal Ingestion and Platform Cooling Experiments

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Total Pages : pages
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Book Synopsis Turbine Rim Seal Ingestion and Platform Cooling Experiments by : William A. Daniels

Download or read book Turbine Rim Seal Ingestion and Platform Cooling Experiments written by William A. Daniels and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Large-eddy Simulation of Turbine Rim Seals

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Total Pages : pages
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Book Synopsis Large-eddy Simulation of Turbine Rim Seals by : T. S. D. O'Mahoney

Download or read book Large-eddy Simulation of Turbine Rim Seals written by T. S. D. O'Mahoney and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the application of Large-Eddy Simulation (LES) to the internal flows within turbomachines. In particular, the work sought to investigate whether LES could give an improved predictive tool for flows through a turbine rim seal where other methods of modelling turbulence give disappointing results for the simulation of hot annulus gas ingestion into the rim seal cavity. The applicability of LES to flow regimes within a rotor-stator cavity were investigated with reference to two experimental studies, those of Daily & Nece [1] and of Itoh et al. [2]. LES simulations were run using the commercial Computational Fluid Dynamics (CFD) code FLUENT and the Rolls-Royce CFD code HYDRA. Both gave good agreement for the velocity field even when the boundary layer was not fully resolved. HYDRA was then used to simulate a turbine rim seal cavity with external flow through an annulus with NGV and rotor blades, modelled using a small sector with periodic boundary conditions in the circumferential direction. LES was found to predict higher levels of ingestion than Unsteady Reynolds- Averaged Navier-Stokes (URANS) simulations at a number of different values of cavity throughflow. This resulted in better, but not close, agreement with the experiments of Gentilhomme [3]. The sensitivity of the LES to changes in the size of the sector and to the resolution of the CFD grid were investigated. A larger sector simulation, corresponding to 40°, gave almost identical results to those on the smaller sector, 13.3°. Refinement to the CFD grid did lead to different results, particularly in the annulus flow, though critically the prediction of ingestion in the stator boundary layer was largely unaffected.

Aerodynamics of Turbine Rim-seal Ingestion

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ISBN 13 :
Total Pages : 9 pages
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Book Synopsis Aerodynamics of Turbine Rim-seal Ingestion by : Nicholas J. Hills

Download or read book Aerodynamics of Turbine Rim-seal Ingestion written by Nicholas J. Hills and published by . This book was released on 1997 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Sealing Effectiveness of a Turbine Rim Seal at Engine-Relevant Conditions

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ISBN 13 :
Total Pages : pages
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Book Synopsis Sealing Effectiveness of a Turbine Rim Seal at Engine-Relevant Conditions by : Kenneth Clark

Download or read book Sealing Effectiveness of a Turbine Rim Seal at Engine-Relevant Conditions written by Kenneth Clark and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas turbines are characterized by high efficiencies compared to other power generation systems, but even small efficiency gains can result in huge reductions in fuel costs and emissions. Overall pressure ratios for gas turbines continue to rise to achieve higher efficiencies, resulting in increasingly extreme thermal conditions in the hot section of the engine. Secondary air, bled from the compressor, is used to cool turbine components and seal the inter-stage cavities from the hot main gas path to maintain component durability. Unsealed cavities lead to hot gas ingestion, which can degrade critical components or, in extreme cases, can be catastrophic to engines. Providing adequate sealing flow is required to maintain component life, but efficient use of the secondary air is required to maintain the thermodynamic efficiency of the engine. To fully optimize these competing requirements, experiments at engine-relevant conditions are required to validate new designs and computational tools. This dissertation presents sealing effectiveness measurements for an engine-realistic turbine rim seal operated at engine-relevant conditions.A new facility providing continuous flow for a 1.5 stage turbine was designed, constructed, and commissioned to study hot gas ingestion for at engine-relevant conditions. Sealing effectiveness was determined through concentration measurements, whereby CO2 was used as a tracer gas in the secondary air supply, and sampled throughout the turbine rim seal and rim cavity. The turbine design was representative of a modern turbine with engine-realistic purge flow delivery and leakage flows, resulting in complex flow fields in the cavities. The measurements indicated that sealing effectiveness depended on the number of purge holes at and inboard of the purge injection location, with more purge holes exhibiting higher effectiveness than fewer purge holes. Outboard of the purge location, the sealing effectiveness was not affected by the number of purge holes. The boundary layer on the rotating disk entrained the purge flow, and the rotor and stator pumping distributed the purge flow throughout the cavity reducing the amount of ingestion. The results indicated that the well-accepted orifice models used to predict sealing effectiveness throughout the industry are successful for some cases; however, the results in this dissertation showed that those models are unsuccessful in predicting sealing effectiveness for the complex engine-realistic geometries and purge flow delivery methods. These findings highlight the need to obtain sealing effectiveness data at engine-relevant conditions, using engine-realistic hardware to develop ingestion models applicable to gas turbine engines.

Characterization of Turbine Rim Seal Flow and Its Sealing Effectiveness

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ISBN 13 :
Total Pages : 84 pages
Book Rating : 4.:/5 (862 download)

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Book Synopsis Characterization of Turbine Rim Seal Flow and Its Sealing Effectiveness by : Peter T. Catalfamo

Download or read book Characterization of Turbine Rim Seal Flow and Its Sealing Effectiveness written by Peter T. Catalfamo and published by . This book was released on 2013 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a gas turbine engine, ingestion of hot gas from the flowpath into the gaps between the turbine rotor and stator can lead to elevated metal temperatures and a deterioration of component life. To prevent ingestion, bleed air from the compressor is used to "purge" the rim seal cavities. Establishing a quantitative understanding of the wheelspace and rim cavity flow processes driving ingestion is critical to optimizing seal design and minimizing the associated performance penalty. A computational model of the wheelspace that does not limit the spatial or temporal scales of flow processes is formulated. This allows the assessment of the response of the wheelspace to external stimuli set up by the turbine main flow path, and the development of causal links between flow processes and their drivers. Varying the axisymmetric turbine flowpath pressure on a quasi-steady basis when the purge flow supply seal is choked has no impact on ingestion; the pressure field in the wheelspace merely scales with the flowpath pressure, leaving the flow structure unchanged. Introducing circumferential variation in the external pressure field can, however, lead to ingestion with the ratio of disturbance wavelength to the trench depth emerging as a key parameter. Varying rotational speed alone does not drive ingestion as a stagnation point is formed on the outer shroud that is ingestion resistant. It is shown that excitation at frequencies corresponding to the natural modes of the wheelspace system can lead to large responses in pressure and seal flow rate, with the seal reduced frequency appearing as a characterizing parameter. The existence and parametric dependence of these modes is further assessed through a small disturbance flow analysis. A generalized small disturbance flow analysis is formulated that provides a direct enumeration of the key characterizing parameters.

Paper

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Total Pages : 458 pages
Book Rating : 4.3/5 (91 download)

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Book Synopsis Paper by :

Download or read book Paper written by and published by . This book was released on 2001 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:

An Investigation of Rim Seal/Disk Cavity Flow and Its Interaction with High Pressure Turbine Rotor Flows

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Book Synopsis An Investigation of Rim Seal/Disk Cavity Flow and Its Interaction with High Pressure Turbine Rotor Flows by : Jason Town

Download or read book An Investigation of Rim Seal/Disk Cavity Flow and Its Interaction with High Pressure Turbine Rotor Flows written by Jason Town and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ingestion and egression of hot gas path fluid into the rim seal cavity of an axial flow turbine is usually mitigated by the use of purge flow. The purge flow arrives into a disk cavity space from the final stage of the compressor and is very expensive in terms of total system efficiency. Cycle analysis for a gas turbine clearly indicates the significant efficiency penalty for the use of high pressure compressor air for cooling or disk cavity space purge action. Furthermore, the purge flow modifies flow structures inside and downstream of the cavity where the purge flow mixes with hot mainstream gasses. This thesis provides an understanding of the modes of ingestion and egression of the rim seal cavity. A review of previous studies pertaining to the effects of purge ingress/egress and methods of mitigation is provided. New testing in a simulated disk cavity space is performed at the Axial Flow Turbine Research Facility (AFTRF) using a representative, modern High Pressure Turbine (HPT) stage. A complete set of aerodynamic instrumentation is designed, assembled and validated for shakedown testing of the AFTRF. A new aerodynamic probe management system allowing for adaptive gridding in the intraspace and rotor exit frames is designed, built, and validated. This system, by moving more efficiently, increases the number of measurement locations taken in a two hour run from 336 points to 868. Using this measurement system, total pressure measurements from a Kiel probe and a Five Hole Probe downstream of the Nozzle Guide Vane (NGV) are shown to agree with each other. In the rotating frame of the AFTRF-HPT, a new 32 channel electronic pressure measurement system is implemented to measure vane and blade loadings. Vane loadings have a variation of approximately 1% from run to run and agree well with computational results. A correction for blade loading in the relative frame of reference is applied and results have a variation of 1% from run to run and agree reasonably well with predictions. Dynamic measurements of total pressure at the rotor exit, which are phase-locked with the rotor position, allow inspection of the unique flow structures generated by each passage. The next phase of testing includes varying purge rates of the rim seal cavity, modification of the rim seal cavity, changing the rotor blades to a design to control the tip leakage, and comparing experimental measurements and computational predictions of unsteady structures within the rim seal cavity. It is found that the 'Baseline Blades' preform less well than the 'Tip Vortex Control (TVC) Blades'. Two tip treatments are tested, smooth and slotted, slotted tip treatments are beneficial to the 'Baseline Blades' and detrimental to the 'TVC Blades' when compared to the smooth tip treatments. Of the two rim seal cavity designs, the modified design used with the 'TVC Blades' with reduced radial clearance reduces the penetration and momentum deficit in the region of the hub endwall passage vortex. Experimentally measured unsteady structures within the rim seal cavity are measured using fast response aerodynamic piezoresistive transducers. They are then compared to an unsteady transient eight vane, ten blade computations. A method to extract the speed at which these structures are moving and the number of structures present is given for both the experimental and computational ways. Within the rim seal cavity 15 unsteady pressure cells moving at 77.5% of the rotor speed are experimentally measured and though the computational methods 14.5 unsteady pressure cells are moving at 81.7% rotor speed.

ASME Technical Papers

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ISBN 13 :
Total Pages : 446 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis ASME Technical Papers by :

Download or read book ASME Technical Papers written by and published by . This book was released on 2001 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt:

UTRC Turbine Rim Seal Ingestion and Platform Cooling Experiments

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Book Synopsis UTRC Turbine Rim Seal Ingestion and Platform Cooling Experiments by : John M. Feiereisen

Download or read book UTRC Turbine Rim Seal Ingestion and Platform Cooling Experiments written by John M. Feiereisen and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Characterization of Ingestion Through the Rim Seal of Rotor-stator Disk Cavity in a Subscale Single-stage Axial Turbine

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Total Pages : 75 pages
Book Rating : 4.:/5 (898 download)

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Book Synopsis Characterization of Ingestion Through the Rim Seal of Rotor-stator Disk Cavity in a Subscale Single-stage Axial Turbine by : Prashant Singh

Download or read book Characterization of Ingestion Through the Rim Seal of Rotor-stator Disk Cavity in a Subscale Single-stage Axial Turbine written by Prashant Singh and published by . This book was released on 2014 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to achieve higher gas turbine efficiency, the main gas temperature at turbine inlet has been steadily increased from approximately 900°C to about 1500°C over the last few decades. This temperature is higher than the maximum acceptable temperature for turbine internals. The hot main gas may get ingested into the space between rotor and stator, the rotor-stator disk cavity in a stage because of the pressure differential between main gas annulus and the disk cavity. To reduce this ingestion, the disk cavity is equipped with a rim seal; additionally, secondary (purge) air is supplied to the cavity. Since the purge air is typically bled off the compressor discharge, this reducing the overall gas turbine efficiency, much research has been carried out to estimate the minimum purge flow necessary (cw, min) for complete sealing of disk cavities. In this work, experiments have been performed in a subscale single-stage axial turbine featuring vanes, blades and an axially-overlapping radial-clearance seal at the disk cavity rim. The turbine stage is also equipped with a labyrinth seal radially inboard. The stage geometry and the experimental conditions were such that the ingestion into the disk cavity was driven by the pressure asymmetry in the main gas annulus. In the experiments, time-averaged static pressure was measured at several locations in the main annulus and in the disk cavity; the pressure differential between a location on the vane platform close to lip (this being the rim seal part on the stator) and a location in the 'seal region' in the cavity is considered to be the driving potential for both ingestion and egress. Time-averaged volumetric concentration of the tracer gas (CO2) in the purge air supplied was measured at multiple radial locations on the stator surface. The pressure and ingestion data were then used to calculate the ingestion and egress discharge coefficients for a range of purge flow rates, employing a simple orifice model of the rim seal. For the experiments performed, the egress discharge coefficient increased and the ingestion discharge coefficient decreased with the purge air flow rate. A method for estimation of cw, min is also proposed.

An Experimental Study of Ingress Through Gas-turbine Rim Seals

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Book Synopsis An Experimental Study of Ingress Through Gas-turbine Rim Seals by : Fabian Patricio Hualca-Tigsilema

Download or read book An Experimental Study of Ingress Through Gas-turbine Rim Seals written by Fabian Patricio Hualca-Tigsilema and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: