The Acoustic Influence of Cell Depth on the Rotordynamic Characteristics of Smooth-Rotor/Honeycomb-Stator Annular Gas Seals

Kleynhans, George F.; Childs, Dara W.

doi:10.1115/96-gt-122

Cited by 6 publications

(7 citation statements)

References 4 publications

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“…Table 5 provides the calculated leakage rate using the different methods for the hole-pattern seal. It indicates the leakage rate with the present elliptical orbit model agrees better with the experimental data than that of isothermal two-control-volume bulk flow model 10 and unidirectional shaking model. 6 For the leakage rate computation, the elliptical orbit model almost has the same accuracy as the circular orbit model, while the leakage rate from isothermal twocontrol-volume bulk flow model 10 is nearly the same as the unidirectional shaking model.…”

Section: Numerical Resultssupporting

confidence: 67%

“…This indicates that both the circular 7 and elliptical orbit models (this article) have the same accuracy. And moreover, both the circular and elliptical orbit models have a superior accuracy than that of unidirectional shaking model 6 and ISOTSEAL 10 with respect to the experimental test. 4 It can be concluded that, for the unidirectional shaking model, only one-directional rotor motion will lead to loss of fluid-solid interaction information in the numerical computations.…”

Section: Numerical Resultsmentioning

confidence: 92%

“…For the annular gas seal, the rotordynamic coefficients were initially solved using the simplified one-control-volume bulk flow model. 8 Subsequently, Ha and Childs, 9 Kleynhans and Childs, 10 and Soulas and San Andres 11 presented the two-control-volume bulk flow method which is available to predict the rotordynamic performance of the honeycomb (or hole-pattern seal) seal. However, for the two-control-volume bulk flow method, several drawbacks as follows still need to be tackled.…”

Section: Introductionmentioning

confidence: 99%

“…In their studies, Chochua and Soulas's 6 unidirectional shaking model was modified into a circular orbit model. Yan et al's 7 numerical results show that the transient CFD method based on the circular orbit model has a superior accuracy to the two-control-volume bulk flow analysis 10 and unidirectional shaking model. 6 However, this method (circular orbit model) requires twice of transient computations (forward and backward orbit computations) for a certain excitation frequency thus double the computational time.…”

Section: Introductionmentioning

confidence: 99%

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Rotordynamic performance prediction for surface-roughened seal using transient computational fluid dynamics and elliptical orbit model

Yan

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part A:

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This article presents a transient computational fluid dynamics method based on the elliptical orbit model to solve the rotordynamic coefficients of the non-axisymmetric rotating turbomachinery. To validate the numerical approach, an arbitrary stator roughened seal, named hole-pattern seal, is taken as an object to investigate the rotordynamic performance at different excitation frequencies. For each case, the transient fluid force is computed by integrating the unsteady pressure on the off-centered rotor surface. The rotordynamic coefficients are obtained by solving the frequency dependent reaction force/seal motion equations. The transient pressure distributions on the rotor and stator are plotted to analyze the influence of the rotor precession on the pressure fluctuation during a period. It shows that the computed leakage rate and rotordynamic coefficients for the hole-pattern seal agree well with the experimental data. Compared to the previous circular orbit model, the present numerical approach for the elliptical orbit model has equivalently high accuracy, but the consumed transient solution time is reduced by 50%.

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Section: Numerical Resultssupporting

confidence: 67%

Section: Numerical Resultsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Rotordynamic performance prediction for surface-roughened seal using transient computational fluid dynamics and elliptical orbit model

Yan

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…A simulator called ISOTSEAL, developed at Texas A&M University, offers a relatively speedy evaluation (about one second) of the response(s) of interest for the honeycomb seal under study at BHGE. ISOTSEAL is built on bulk‐flow theory, calculating gas seal force coefficients based on seal flow physics.…”

Section: Honeycomb Sealmentioning

confidence: 99%

On‐site surrogates for large‐scale calibration

Huang

Gramacy

Binois

et al. 2020

Appl Stoch Models Bus & Ind

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Motivated by a computer model calibration problem from the oil and gas industry, involving the design of a honeycomb seal, we develop a new Bayesian methodology to cope with limitations in the canonical apparatus stemming from several factors. We propose a new strategy of on-site design and surrogate modeling for a computer simulator acting on a high-dimensional input space that, although relatively speedy, is prone to numerical instabilities, missing data, and nonstationary dynamics. Our aim is to strike a balance between data-faithful modeling and computational tractability in a calibration framework-tailoring the computer model to a limited field experiment. Situating our on-site surrogates within the canonical calibration apparatus requires updates to that framework. We describe a novel yet intuitive Bayesian setup that carefully decomposes otherwise prohibitively large matrices by exploiting the sparse blockwise structure. Empirical illustrations demonstrate that this approach performs well on toy data and our motivating honeycomb example. K E Y W O R D SBayesian calibration, big data, computer experiment, local Gaussian process, hierarchical model, uncertainty quantification INTRODUCTIONWith remarkable advances in computing power, today's complex physical systems can be simulated comparatively cheaply and to high accuracy by using mature libraries. The ability to simulate has dramatically driven down the cost of scientific inquiry in engineering settings, at least at initial proof-of-concept stages. Even so, computer models often idealize the system-they are biased-or require the setting of tuning parameters: inputs unknown or uncontrollable in actual physical processes in the field. An excellent example is the simulation of a free-falling object, which is a potentially involved if well-understood enterprise from a modeling perspective. Acceleration due to gravity might be known, but possibly not precisely. Coefficients of drag may be completely unknown. A model incorporating both factors but not others such as ambient air disturbance or rotational velocity could be biased in consistent but unpredictable ways.Researchers are interested in calibrating such models to experimental data. With a flexible yet sturdy apparatus, a limited number of field observations from physical experiments can provide valuable information to fine tune, improve fidelity, understand uncertainty, and correct bias between simulations and physical phenomena they model. When done right, tuned and bias-corrected simulations are more realistic, forecasts more reliable, and these can inform simulation redevelopment, if necessary.Appl Stochastic Models Bus Ind. 2020;36:283-304.wileyonlinelibrary.com/journal/asmb

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Experimental investigation of air bearings dynamic coefficients

Matta

Rudloff

Arghir

2010

Mécanique & Industries

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The paper presents the experimental work developed by the authors for the identification of rotordynamic coefficients of air bearings. Air bearings work at very high rotation speeds and are known to have nonlinear dynamic characteristics depending at least on the excitation frequency. The paper presents two very similar test rigs, the testing procedure and the algorithm for identifying the rotordynamic coefficients. The test rigs consist of a rigid rotor guided by fixed bearings and driven by a spindle. The dynamic loads are applied by two orthogonally mounted shakers applying two linear independent excitations. Two air bearings are analysed in the present paper. The test procedure is first developed for a simple circular bearing with easily predictable dynamic characteristics. Its rotordynamic coefficients are identified by using a least square procedure based on rational functions. The coefficients are compared to theoretical results in order to underline the limits of the identification algorithm. The procedure is next applied to a first generation foil bearing. Rotordynamic coefficients are presented for different working conditions (static loads and rotation speeds) and are discussed comparing them to circular air bearings.

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The Acoustic Influence of Cell Depth on the Rotordynamic Characteristics of Smooth-Rotor/Honeycomb-Stator Annular Gas Seals

Cited by 6 publications

References 4 publications

Rotordynamic performance prediction for surface-roughened seal using transient computational fluid dynamics and elliptical orbit model

Rotordynamic performance prediction for surface-roughened seal using transient computational fluid dynamics and elliptical orbit model

On‐site surrogates for large‐scale calibration

Experimental investigation of air bearings dynamic coefficients

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