Turbomachinery Clearance Control

Chupp, Raymond E.; Hendricks, R. C.; Lattime, Scott B.; Steinetz, Bruce M.; Akşit, Mahmut Faruk

doi:10.2514/5.9781624102660.0061.0188

Cited by 7 publications

(16 citation statements)

References 99 publications

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“…Cloth and shim materials are selected as Haynes 25/L605 and Haynes 188, respectively. The direction of cloth weave is oriented 45 • to the dominant relative motion (diagonal direction), which increases wear resistance and helps mesh integrity [24]. Therefore, cloth weave is oriented in a diagonal direction and welded with shims.…”

Section: Resultsmentioning

confidence: 99%

“…Screening experiments are performed with the fractional factorial experiment design. Similar to the previous studies [12,24] applied, leakage rates are nondimensionalized and normalized by dividing the leakage rates with that of the rigid seal under baseline (without offset and mismatch) position at the condition that pressure drop is equal to downstream pressure (P low /P high = 0.5). The parameters for the baseline rigid seal test are slot distance = 32 mm, shim width = 26 mm, gap = 4 mm, shim thickness = 0.254 mm, surface roughness = 6.4 µm, pressure drop = 101.3 kPad, offset = 0 mm, and mismatch = 0 • .…”

Section: Screening Experiments Resultsmentioning

confidence: 99%

“…Therefore, the last ten parameters (parameters 9-18) are fixed at common values based on engineering judgment and literature data. Cloth material is selected as cobalt-based alloy Haynes 25/L605 which has superior high temperature wear resistance, and is used as common cloth material [3,24]. Haynes alloy 188 has good oxidation resistance for high temperature, and is commonly used as shim material in cloth seals [24].…”

Section: Experimental Designmentioning

confidence: 99%

“…Cloth material is selected as cobalt-based alloy Haynes 25/L605 which has superior high temperature wear resistance, and is used as common cloth material [3,24]. Haynes alloy 188 has good oxidation resistance for high temperature, and is commonly used as shim material in cloth seals [24]. The data provided in the literature indicates that Dutch Twill with 30 × 250 per inch density provides better leakage performance and is commonly used as the cloth of choice in cloth seals [23].…”

Section: Experimental Designmentioning

confidence: 99%

“…Therefore, leakage performance has been studied at different pressure levels. In order to reduce the number of parameters to a manageable size, some of the parameters are fixed and excluded from the experimental design based on the studies in the literature [23,24]. The remaining eight parameters are included in the screening experiments.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A Study of Cloth Seal Leakage Performance Based on Geometry and Pressure Load

2020

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Metal cloth seals have been used increasingly in gas turbines due to their flexibility and superior leakage performance. Leakage performance of a metal cloth seal depends on operating conditions, slot and geometric dimensions. These parameters need to be investigated for the best leakage performance. In this study, pressure drop and critical geometric parameters of typical cloth seal form are investigated with an experimental setup. Slot depth, cloth width, sealing gap, shim thickness, surface roughness, pressure drop, offset and mismatch are selected parameters for the screening experiments. Sixteen experiments were conducted following a two-level Resolution IV fractional factorial experiment design for eight parameters. The results indicated that strong parameters for the leakage performance are pressure drop, cloth width, slot depth and offset. Leakage rate is increased with an increase in slot depth, gap, shim thickness, pressure drop and mismatch. During screening experiments, the experiment with minimum flow rate has 86% lower leakage rate than the experiment with maximum flow rate. For main experiments, a Box-Behnken experiment design is applied to analyze nonlinear effects of four strong parameters on the leakage rate. A closed-form equation is derived based on the data and presented in this study.

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Section: Resultsmentioning

confidence: 99%

Section: Screening Experiments Resultsmentioning

confidence: 99%

Section: Experimental Designmentioning

confidence: 99%

Section: Experimental Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Study of Cloth Seal Leakage Performance Based on Geometry and Pressure Load

2020

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PALS - An Auspicious New Gas Turbine Seal

Langston

2016

Mechanical Engineering

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This article highlights various aspects of a new gas turbine shaft seal called the pressure activated leaf seal (PALS). The paper in detail discusses the architecture and working of a gas turbine seal. PALS is designed to use changing pressure drop forces across the seal to eliminate rub. The seal elements stay clear of the rotor seal surface during start-up and shutdown transients, and subsequently close to a small, non-contacting, steady-state running clearance. During start-up or shutdown, when the axial pressure difference across PALS is small, the leaves are in a relaxed open position, providing a general clearance gap for possible rotor seal surface eccentricities. At operating speeds, the resulting axial pressure difference causes the leaf element to elastically deflect and close, reaching the design clearance when they contact the support member. The test results show that the PALS concept provides for a potentially viable, robust, low leakage seal for gas turbine applications.

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Dynamic Characterization of an Adaptive Film-Riding Seal

Bird,

Keogh,

Sangan

et al. 2023

Journal of Engineering for Gas Turbines and Power

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Shaft seals control the leakage of fluid between areas of high pressure and low pressure around rotating components inside turbomachinery. Static seals are often subject to damaging rubs with the shaft, caused by assembly misalignments and rotordynamic vibrations during operation. Adaptive seals aim to reduce leakage flows whilst minimizing wear. The Film Riding Pressure Actuated Leaf Seal (FRPALS) is one such design which utilizes a large installation clearance and is blown down towards the shaft under pressure. This paper presents a numerical model which can be used in the design and development of adaptive shaft seals, validated by experimental data from the literature. The model uses a modified version of the Reynolds equation to predict the dynamic, frequency-dependent stiffness and damping coefficients of the fluid film. The dynamic coefficients have been solved for different operational clearances and pressure differences to generate coefficient maps. These maps have been incorporated into a blow down model with compliant mechanical leaves to predict the transient translational and angular displacement paths of the FRPALS when subject to an increasing pressure drop. The blow down model has been compared against experimental measurements collected from a specially designed test facility for the characterization of shaft seal performance. Eddy current probes were used to measure the displacement paths of the FRPALS with the experimental values showing that the model can accurately predict the dynamic movement of the seal when subject to a pressure difference.

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Turbomachinery Clearance Control

Abstract: Acronym List

Cited by 7 publications

References 99 publications

A Study of Cloth Seal Leakage Performance Based on Geometry and Pressure Load

A Study of Cloth Seal Leakage Performance Based on Geometry and Pressure Load

PALS - An Auspicious New Gas Turbine Seal

Dynamic Characterization of an Adaptive Film-Riding Seal

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