Design and Development of a Full-Scale Generic Transient Heat Transfer Facility (THTF) for Air System Validation

Paridon, Andrew van; Dann, Andrew; Ireland, Peter T.; Bacic, Marko

doi:10.1115/gt2015-42391

Cited by 3 publications

(4 citation statements)

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“…The system would simply need to increase the case temperature to cause it to expand, thus opening up seal clearances. To the authors' knowledge, no aeronautical gas turbines use active clearance control in the compressor to treat rotor bow; however, there is growing interest in active clearance control in compressors to manage transient changes in clearance during the various phases of flight (57)(58)(59) , and there may be opportunities to use system to reduce the likelihood of Newkirk Effect.…”

Section: Active Clearance Control On Start-upmentioning

confidence: 99%

The impact of gas turbine compressor rotor bow on aircraft operations

2017

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When a gas turbine engine is shut down it will develop a circumferential thermal gradient vertically across the compressor due to hot air rising from the cooling metal components and pooling at the top. As the hot compressor rotor drum and casing cool and contract in the presence of this thermal gradient, they do so non-uniformly and therefore will bend slightly, in a phenomenon known as rotor bow. Starting an engine under bowed conditions can result in damage, representing a risk to both airworthiness and operational capability. This study consolidates some preliminary findings by the authors relating to the drivers for rotor bow, such as engine geometry, aircraft-engine integration and rotor temperature on shutdown. The commercial and military operational considerations associated with rotor bow are also discussed, including limitations which may result from a bowed rotor; the influence of operations including the final flight and descent profiles, taxi procedures and rapid turnaround requirements; as well as some practical solutions which may be implemented to reduce the impact of rotor bow.

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Section: Active Clearance Control On Start-upmentioning

confidence: 99%

The impact of gas turbine compressor rotor bow on aircraft operations

2017

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“…The THTF has been recently commissioned at The University of Oxford. A more detailed description of the rig is given in Van Paridon et al [10]. A brief description is given here to clarify the facility capabilities and operation.…”

Section: Description Of Test Facilitymentioning

confidence: 99%

“…The last point involves matching the higher-stage HP compressor bleed air properties used by the HP and IP turbine secondary air systems. This is challenging due to the prohibitively high costs associated with generating air with these properties, which may require the use of a small gas turbine [10,11] and the use of high temperature materials due to thermomechanical constraints [12].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of Annular Casing Impingement Arrays for Faster Casing Response

Dann

Dhopade

Bacic

et al. 2017

Journal of Engineering for Gas Turbines and Power

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The transient heat transfer facility (THTF) was developed to test full-scale high pressure compressor and turbine casing air systems using gas turbine engine representative secondary air system conditions. Transient casing response together with blade and disk responses governs achievable tip clearances in both compressors and turbines. This paper investigates the use of air impingement as a means to speed up the casing response. The thermal growth of the casing was characterized by surface temperature rise over a given period to assess achievable dynamic response. The experimental setup resembles a typical aircraft engine with features that can lead to circumferential temperature nonuniformities, as evident from the experimental results. The experimental data were compared against numerical predictions from a conjugate heat transfer (CHT) model. The studies show the significance of analyzing the full annulus, at engine representative conditions and the benefit of an impingement array to potentially speed up casing response for future engines.

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“…• generating air with these properties, which may require the use of a small gas turbine [10,11] • the use of high temperature materials due to thermomechanical constraints [12].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of Annular Casing Impingement Arrays for Faster Casing Response

Dann

Dhopade

Bacic

et al. 2016

Volume 5C: Heat Transfer

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The Transient Heat Transfer Facility (THTF) was developed at the University of Oxford to test full-scale high pressure compressor and turbine casing air systems using gas turbine engine representative secondary air system mass flow rates, total temperatures and total pressures. Transient casing response together with blade and disc responses governs achievable tip clearances in both compressors and turbines. Traditionally, casing thermal response is faster than disc response and so requires cooling. However, future engine designs may have thermal responses of the discs that are faster than the casings. In this paper we investigate the use of air impingement as a means to speed up the casing response to match such future designs. Two different impingement configurations were selected from a total of eight designs based on steady Reynolds-averaged Navier-Stokes (RANS) predictions of maximum heat transfer coefficient (HTC). The 3D thermal growth of the casing was characterised by the surface temperature rise over a given period of time to assess achievable dynamic response. The configurations were tested in the THTF as a rainbow set. The resulting casing metal temperatures were used in conjunction with an explicit solution of the conduction in the casing wall to calculate HTC due to impingement. The experimental set-up resembles a typical aircraft engine and therefore includes measurement uncertainties arising from features such as fixtures, seals, geometries and large surface areas that are then subjected to varying thermal inertias. These can lead to circumferential temperature non-uniformities, as evident from the experimental results. An uncertainty analysis was performed to quantify these effects on the overall casing thermal response. The experimental data was then compared against numerical predictions from an axisymmetric, 90° sector, conjugate heat transfer model of the facility using the two impingement plate designs. Overall, the values of HTC agreed well across the experimental and numerical results. Both approaches predicted differences in which of the two designs was more effective; however, advantages and limitations were identified in both approaches. The combined experimental and numerical study shows the significance of analysing the full annulus, at engine representative conditions and the benefit of an impingement array to potentially speed up casing response for future engines.

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Design and Development of a Full-Scale Generic Transient Heat Transfer Facility (THTF) for Air System Validation

Cited by 3 publications

References 0 publications

The impact of gas turbine compressor rotor bow on aircraft operations

The impact of gas turbine compressor rotor bow on aircraft operations

Experimental and Numerical Investigation of Annular Casing Impingement Arrays for Faster Casing Response

Experimental and Numerical Investigation of Annular Casing Impingement Arrays for Faster Casing Response

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