Experimental and Numerical Development of a Dynamic Clearance Seal for Steam Turbine Application

Messenger, Andrew; Williams, Richard; Ingram, Grant; Hogg, Simon; Tibos, Stacie; Seaton, Jon; Charnley, B.

doi:10.1115/gt2016-56995

Cited by 2 publications

(5 citation statements)

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“…A similar effect was observed in a non-rotating test facility [3], and so is not due to the addition of shaft rotation. Although there appears to be a slight vibration on the other seal segments in Fig.…”

Section: Typical Seal Response At Low Eccentricity and 1500 Rpmsupporting

confidence: 54%

“…Tests conducted with a low level of rotor eccentricity showed that operation of the seal was similar to the retractable seal. Seal operation was as expected from previous tests conducted in a non-rotating facility [3]. The seal response was dependant on the circumferential position of the seal segment.…”

Section: Discussionmentioning

confidence: 49%

“…High steam temperatures and the use of realistic steam turbine materials will alter the level of friction between the seal segments and the seal holder. It has previously been shown that the level of friction affects Aerostatic Seal performance [3] and designs which are robust to variations in friction level are under consideration.…”

Section: Discussionmentioning

confidence: 99%

“…This was achieved in a nonrotating test facility using air instead of steam [2,3]. The advance presented here is the validation of the Aerostatic Seal in a rotating seals rig that features an eccentric rotor allowing radial rotor transients to be simulated.…”

Section: Introductionmentioning

confidence: 99%

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Demonstration of a Dynamic Clearance Seal in a Rotating Test Facility

Messenger

Williams

Ingram

et al. 2017

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTThe successful demonstration of the "Aerostatic Seal" in a half scale rotating facility is described in this paper. The Aerostatic seal is a novel dynamic clearance seal specifically designed for steam turbine secondary gas path applications. The seal responds to radial rotor excursions, so a reduced clearance can be maintained compared to conventional labyrinth seal without damage to the seal. This enables increased turbine performance through reduced leakage and increased tolerance of turbine transient events typically found during start up. The seal is an extension of the existing retractable seal design already deployed in commercial steam turbines.The seal was tested in the Durham Rotating Seals Rig, which was developed specifically to test this device. The rig featured a rotor designed to run with large eccentricities to model high speed radial rotor excursions, and the seal was instrumented to measure the real time seal response to the rotor.The experimental campaign has conclusively demonstrated the ability of the seal to dynamically respond to the rotor position. The key result is that the seal is able to track the rotor position at high speed, and hence maintain a mean seal clearance that is lower than the rotor eccentricity. Overall this work marks a key milestone in the development of the Aerostatic Seal, and leads the way to testing in a steam environment and application in steam turbine plant. * Address all correspondence to this author. NOMENCLATURE INTRODUCTIONIn recent years an increased level of intermittent generation on the electrical grid has resulted in the requirement for conventional generators to operate more flexibly to meet electrical demand and remain profitable. For a steam turbine, flexibility in operation requires faster load changes, in turn leading to frequent transient radial rotor excursions and thermal expansions. Seals can then become damaged, reducing turbine efficiency and output power. A dynamic seal, which is a seal that can respond to the position of the rotor surface, offers major advantages over the conventional labyrinth seal. Not only can they accommodate rotor excursions, but they can operate at lower clearance, reducing leakage and hence increasing turbine efficiency. The "Aerostatic Seal", shown in Fig. 1, is a dynamic seal concept that is tested in this paper.The Aerostatic Seal is a development of the retractable seal used in steam turbines for a number of years. The seal is made up from a number of circumferential seal segmen...

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Section: Typical Seal Response At Low Eccentricity and 1500 Rpmsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 49%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Demonstration of a Dynamic Clearance Seal in a Rotating Test Facility

Messenger

Williams

Ingram

et al. 2017

Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines

Self Cite

View full text Add to dashboard Cite

show abstract

“…One of the studied types of aerostatic seal is an externally pressurized labyrinth. Messenger et al [16,17] have developed and experimentally validated such aerostatic sealing system for turbomachinery. The seal in Messenger's studies was pressurized from the high pressure side of the seal and was preloaded to not contact the shaft at low pressures.…”

Section: Introductionmentioning

confidence: 99%