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Journal articles on the topic 'Labyrinth Seals'

Author: Grafiati
Published: 4 June 2021
Last updated: 6 September 2023

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1

Zhang, Xiumin, Mingfu Yin, and Huilai Sun. "Establishment and solution of governing equation for plana-grooved liquid seals based on three-control-volume theory." Industrial Lubrication and Tribology 72, no. 3 (November 18, 2019): 257–66. http://dx.doi.org/10.1108/ilt-06-2019-0228.

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Purpose This paper aims to study the dynamic characteristics of the straight-through labyrinth seals, which is applied on an oil sealing belt of hydrostatic support system (HSS) oil pocket, the establishment and solution process of seal governing equation is deduced. Design/methodology/approach The three-control-volume model theory is an efficient approach that is applied well. This paper starts with three relative governing equations for the flow characteristics of straight-through labyrinth seals in the plane direction. Referring to the establishment process of governing equations for circumferentially-grooved liquid seals, the governing equation based on space rectangular coordinate system is established, which are transformed into dimensionless equations through a nondimensionalized process and solved by a perturbation method. It contains a zeroth-order equation, through which a steady fluid distribution is determined, and a first-order equation, through which the seal’s dynamic coefficients can be acquired. Findings The governing equation for plane-grooved straight-through labyrinth seals can be established and solved by the three-control-volume theory. Practical implications This study have important guiding significance for further theoretical research and structural design of the straight-through labyrinth seals on the oil sealing belt of HSS oil pocket. Originality/value In this paper, a straight-through labyrinth seal is installed in an oil sealing belt. The three-control-volume governing equations is established in space rectangular coordinate system, and the shear force of the fluid Y-direction is different from the previous model.
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2

Lorencin, Ivan, Nikola Anđelić, Vedran Mrzljak, and Zlatan Car. "Exergy analysis of marine steam turbine labyrinth (gland) seals." Pomorstvo 33, no. 1 (June 28, 2019): 76–83. http://dx.doi.org/10.31217/p.33.1.8.

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The paper presents an exergy analysis of marine steam turbine labyrinth (gland) seals - an inevitable component of any marine steam turbine cylinder, in three different operating regimes. Throughout labyrinth seals, steam specific enthalpy can be considered as a constant because the results obtained by this assumption do not deviate significantly from the results of complex numerical models. Changes in labyrinth seals exergy efficiency and specific exergy destruction are reverse proportional. The analyzed labyrinth seals have high exergy efficiencies in each observed operating regime at the ambient temperature of 298 K (above 92%), what indicates seals proper operation. An increase in the ambient temperature resulted with a decrease in labyrinth seals exergy efficiency, but even at the highest observed ambient temperature of 318 K, seals exergy efficiency did not fall below 90.5% in each observed operating regime.
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3

Soto, E. A., and D. W. Childs. "Experimental Rotordynamic Coefficient Results for (a) a Labyrinth Seal With and Without Shunt Injection and (b) a Honeycomb Seal." Journal of Engineering for Gas Turbines and Power 121, no. 1 (January 1, 1999): 153–59. http://dx.doi.org/10.1115/1.2816303.

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Centrifugal compressors are increasingly required to operate at higher pressures, speeds, and fluid density. In these conditions, compressors are susceptible to rotordynamic instabilities. To remedy this situation, labyrinth seals have sometimes been modified by using shunt injection. In shunt injection, the gas is taken from the diffuser or discharge volute and injected into an upstream chamber of the balance-piston labyrinth seal. The injection direction can be radial or against rotation. This study contains the first measured rotordynamic data for labyrinth seals with shunt injection. A comparison has been made between conventional labyrinth seals, labyrinth seals with shunt injection (radial and against rotation), and a honeycomb seal. Labyrinth seals with injection against rotation are better able to control rotordynamic instabilities than labyrinth seals with radial injection; however, the leakage is slightly higher. The leakage comparison for all seals demonstrates that the honeycomb seal has the best flow control. Test data are presented for a top rotor surface velocity of 110 m/sec, a supply pressure of 13.7 bars, and IPr = 0.95 (injection pressure is 1.05 = 1/0.95 times the seal inlet pressure). For these conditions, and considering effective damping, the labyrinth seal with injection against rotation is better than the honeycomb seal when the pressure ratio across the seal PR < 0.45. On the other hand, the honeycomb seal is better when PR > 0.45. The effectiveness of the shunt-injection against rotation in developing effective damping is reduced with increasing rotor surface velocity.
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4

Chupp, R. E., and C. A. Dowler. "Performance Characteristics of Brush Seals for Limited-Life Engines." Journal of Engineering for Gas Turbines and Power 115, no. 2 (April 1, 1993): 390–96. http://dx.doi.org/10.1115/1.2906721.

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Brush seals are potential replacements for air-to-air labyrinth seals in gas turbine engines. An investigation has been conducted to determine the performance characteristics of brush seals for application in limited-life gas turbine engines. An elevated temperature, rotating test rig was designed and built to test labyrinth and brush seals in simulated subsonic and supersonic engine conditions. Results from initial tests for subsonic applications demonstrated that brush seals exhibit appreciably lower leakage compared to labyrinth seals, and thus offer significant engine performance improvements. Performance results have been obtained showing the effect of various brush seal parameters, including: initial interference, backplate gap, and multiple brush seals in series.
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5

Denecke, J., V. Schramm, S. Kim, and S. Wittig. "Influence of Rub-Grooves on Labyrinth Seal Leakage." Journal of Turbomachinery 125, no. 2 (April 1, 2003): 387–93. http://dx.doi.org/10.1115/1.1539516.

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An experimental investigation on the influence of stator rub-grooves on labyrinth seal leakage is presented in the present paper. In current labyrinth seal designs, abradable lands allow the rotor labyrinth teeth to rub grooves into the stator. These rub-grooves have a large influence on the seal leakage characteristic and impair the overall engine efficiency. To improve the understanding of rub-groove effects, discharge coefficients were determined using a plain nonrotating labyrinth seal model of scale 4:1 considering a wide variation of rub-groove geometries at different seal clearances. Three labyrinth seal types were covered in this investigation that are generally used in gas turbines, namely 1) straight-through labyrinth seals, 2) stepped labyrinth seals with forward facing steps, and 3) stepped labyrinth seals with backward facing steps. To attain a deeper insight into the flow mechanisms, water-channel visualizations were performed. The large data set generated in this study, provides the basis to analyze and quantify the influence of rub-grooves on the seal leakage for the three aforementioned labyrinth seal types. Current results were in agreement with previous studies on worn labyrinth seals for several seal geometries.
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6

Moore, J. Jeffrey. "Three-Dimensional CFD Rotordynamic Analysis of Gas Labyrinth Seals." Journal of Vibration and Acoustics 125, no. 4 (October 1, 2003): 427–33. http://dx.doi.org/10.1115/1.1615248.

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Labyrinth seals are utilized inside turbomachinery to provide noncontacting control of internal leakage. These seals can also play an important role in determining the rotordynamic stability of the machine. Traditional labyrinth seal models are based on bulk-flow assumptions where the fluid is assumed to behave as a rigid body affected by shear stress at the interfaces. To model the labyrinth seal cavity, a single, driven vortex is assumed and relationships for the shear stress and divergence angle of the through flow jet are developed. These models, while efficient to compute, typically show poor prediction for seals with small clearances, high running speed, and high pressure.* In an effort to improve the prediction of these components, this work utilizes three-dimensional computational fluid dynamics (CFD) to model the labyrinth seal flow path by solving the Reynolds Averaged Navier Stokes equations. Unlike bulk-flow techniques, CFD makes no fundamental assumptions on geometry, shear stress at the walls, as well as internal flow structure. The method allows modeling of any arbitrarily shaped domain including stepped and interlocking labyrinths with straight or angled teeth. When only leakage prediction is required, an axisymmetric model is created. To calculate rotordynamic forces, a full 3D, eccentric model is solved. The results demonstrate improved leakage and rotordynamic prediction over bulk-flow approaches compared to experimental measurements.
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7

Wang, Zhiguo, Bo Zhang, Yuanxiang Chen, Sheng Yang, Hongmei Liu, and Honghu Ji. "Investigation of Leakage and Heat Transfer Properties of the Labyrinth Seal on Various Rotation Speed and Geometric Parameters." Coatings 12, no. 5 (April 25, 2022): 586. http://dx.doi.org/10.3390/coatings12050586.

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To investigate the influence of the variation of geometric parameters on the leakage and heat transfer characteristics of labyrinth seals at various rotational speeds, the labyrinth seal models with different geometric parameters were numerically simulated based on the control variable methods. Results show the aerodynamic mechanism of leakage characteristics changing with rotational speed, as well as the leakage characteristics of labyrinth seals under the coupling action of geometric parameters and rotating speeds. When the characteristic scale changes along the direction of centrifugal force, the variation trend of labyrinth seal leakage characteristics is consistent at different rotational speeds. However, the leakage characteristics of labyrinth seals show the difference of rotational speed when the feature scale changes along the axis. At the same time, the laws of convective heat transfer on the surface of the rotor and stator are shown by the results of the studies, which provides reference for the thermodynamic analysis of labyrinth seals.
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8

Wang, Zhiguo, Bo Zhang, Yuanxiang Chen, Sheng Yang, Hongmei Liu, and Honghu Ji. "Investigation of Leakage and Heat Transfer Properties of the Labyrinth Seal on Various Rotation Speed and Geometric Parameters." Coatings 12, no. 5 (April 25, 2022): 586. http://dx.doi.org/10.3390/coatings12050586.

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To investigate the influence of the variation of geometric parameters on the leakage and heat transfer characteristics of labyrinth seals at various rotational speeds, the labyrinth seal models with different geometric parameters were numerically simulated based on the control variable methods. Results show the aerodynamic mechanism of leakage characteristics changing with rotational speed, as well as the leakage characteristics of labyrinth seals under the coupling action of geometric parameters and rotating speeds. When the characteristic scale changes along the direction of centrifugal force, the variation trend of labyrinth seal leakage characteristics is consistent at different rotational speeds. However, the leakage characteristics of labyrinth seals show the difference of rotational speed when the feature scale changes along the axis. At the same time, the laws of convective heat transfer on the surface of the rotor and stator are shown by the results of the studies, which provides reference for the thermodynamic analysis of labyrinth seals.
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9

Childs, D., D. Elrod, and K. Hale. "Annular Honeycomb Seals: Test Results for Leakage and Rotordynamic Coefficients; Comparisons to Labyrinth and Smooth Configurations." Journal of Tribology 111, no. 2 (April 1, 1989): 293–300. http://dx.doi.org/10.1115/1.3261911.

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Test results are presented for leakage and rotordynamic coefficients for seven honeycomb seals. All seals have the same radius, length, and clearance; however, the cell depths and diameters are varied. Rotordynamic data, which are presented, consist of the direct and cross-coupled stiffness coefficients and the direct damping coefficients. The rotordynamic-coefficient data show a considerable sensitivity to changes in cell dimensions; however, no clear trends are identifiable. Comparisons of test data for the honeycomb seals with labyrinth and smooth annular seals shows the honeycomb seal had the best sealing (minimum leakage) performance, followed in order by the labyrinth and smooth seals. For prerotated fluids entering the seal, in the direction of shaft rotation, the honeycomb seal has the best rotordynamic stability followed in order by the labyrinth and smooth. For no prerotation, or fluid prerotation against shaft rotation, the labyrinth seal has the best rotordynamic stability followed in order by the smooth and honeycomb seals.
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10

Jiang, Jie, Yi Yong Yang, Yong Jian Li, and Wei Feng Huang. "Influence of Gas Condensability on Labyrinth Seal's Sealability." Applied Mechanics and Materials 575 (June 2014): 355–62. http://dx.doi.org/10.4028/www.scientific.net/amm.575.355.

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Labyrinth seals are widely used in rotating fluid machinery, due to its simplicity, low-cost and reliability. In this paper, the effect of cavities on leakage loss in straight-through labyrinth seals are studied by changing gas condensability. The fluid flow characteristics through straight-through labyrinth seals are obtained by using viscous flow analysis along with a RNG k-ε turbulence model. The numerical calculation and various gas pressure is that leakage of compressible gas is greater than that of incompressible gas. The result is investigated by the heating effect of labyrinth seal and density characteristics of compressible gas.
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11

Čížek, Michal, and Zdeněk Pátek. "ON CFD INVESTIGATION OF RADIAL CLEARANCE OF LABYRINTH SEALS OF A TURBINE ENGINE." Acta Polytechnica 60, no. 1 (March 2, 2020): 38–48. http://dx.doi.org/10.14311/ap.2020.60.0038.

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Fluid flow in labyrinth seals of a turbine engine is described. The aim is to describe numerical calculations of fluid flow in labyrinth seals and evaluate the calculated data for different settings of radial clearance of labyrinth seals. The results are achieved by 3D CFD detailed simulations in a typical seal geometry. The calculations are performed for different radial clearances at a constant pressure drop. The calculated data are evaluated based on mass flow, static pressure, total enthalpy and total temperature of air. Based on the calculated data, it is visible, that the total temperature of air is increased in the labyrinth seals. The static pressure of air acts as expected –the static pressure is decreased in all teeth. The Mach number is similar in all teeth, but the maximal maximum value is in the last tooth, because of the expansion into the ambient conditions. Results of the calculations are that the total temperature in labyrinth seals is not constant as it is usually presented or supposed usually in common literature.
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12

Chun, Ye Hwan, and Joon Ahn. "Optimizing the Geometric Parameters of a Stepped Labyrinth Seal to Minimize the Discharge Coefficient." Processes 10, no. 10 (October 6, 2022): 2019. http://dx.doi.org/10.3390/pr10102019.

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A series of numerical simulations were performed to study the discharge coefficient based on the geometric parameters of a stepped labyrinth seal that sealed the secondary flow path of a gas turbine. In contrast with straight-through seals, stepped labyrinth seals introduce additional geometrical parameters related to the steps. In this study, three shape variables were observed: step height (SH), position, and cavity width (CW). The sensitivity to the leakage flow of the shape variable in the stepped labyrinth seal was analyzed. The mechanism for improving the sealing performance of stepped labyrinth seals was investigated. The results indicated that the stepped labyrinth seal exhibited up to 17.9% higher leakage-suppression performance than the straight labyrinth seal. Seals with large discharge coefficients had a large vena contracta upstream of each tooth structure and a rapidly accelerated axial velocity in the radial direction. We could observe that the discharge coefficient changed according to the flow field in the cavity. The wall shear stress was sensitive to the SH but not to the CW or step position.
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13

Rhode, D. L., and R. I. Hibbs. "Clearance Effects on Corresponding Annular and Labyrinth Seal Flow Leakage Characteristics." Journal of Tribology 115, no. 4 (October 1, 1993): 699–704. http://dx.doi.org/10.1115/1.2921696.

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A previous Navier-Stokes finite difference computer code is extended in order to compute seal leakage directly from given upstream and downstream reservoir pressures. The numerical results are in excellent agreement with previous measurements, the discrepancy being less than eight percent. Annular seals are found to leak approximately twenty percent more than corresponding labyrinths over the entire range of realistic clearance. A rather unexpected finding is that a dramatic increase of swirl velocity occurs near the discharge of small-clearance annular seals, which does not arise in corresponding labyrinth seals. The results, which are used to explain this finding, show that a large density drop occurs near the small-clearance annular seal exit, which provides the swirl velocity increase in accordance with angular momentum conservation.
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14

Liu, Chunrui, Lidong He, Xingyun Jia, Haozhe Zhu, Tao Chen, and Wenhao Wang. "Effect of Installation Error on Rotary Seal of Aero Engine." Aerospace 9, no. 12 (December 14, 2022): 820. http://dx.doi.org/10.3390/aerospace9120820.

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The rotary seal is a key component of the aero engine. Under actual working conditions, most rotary seals always operate in an eccentric state (caused by installation errors), and when a large eccentricity occurs, it may lead to a large amount of gas leakage, resulting in a decrease in aero engine efficiency, which ultimately affects the reliability and life of the aero engine. Therefore, the effect of installation error on the rotary seal of the aero engine was studied in this research. The flow field numerical models of the honeycomb seal, labyrinth seal, and hybrid labyrinth–honeycomb seal were established, the effects of the honeycomb seal, labyrinth seal, and hybrid labyrinth–honeycomb seal on leakage were numerically analyzed, the sealing mechanisms of three types of seals were revealed, and the effect of radial eccentricity on the leakage of three types of seals was also studied. Additionally, the high-pressure and high-speed rotary seal experiment bench was improved, the effect of eccentricity on the leakage characteristics of the honeycomb seal, labyrinth seal, and hybrid labyrinth–honeycomb seal was studied using the improved experiment bench, and the leakage characteristics of the three types of seals were compared under the same condition. The experimental results are consistent with the numerical simulation results; the honeycomb seal is the least sensitive to eccentricity, and its sealing performance is the best. The research results in this paper reveal the seal mechanisms of the honeycomb seal, labyrinth seal, and hybrid labyrinth–honeycomb seal and demonstrate the effect law of eccentricity regarding the leakage characteristics of these three types of seals. The results of this research can provide theoretical support for aero engine efficiency improvement.
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15

Rhode, D. L., J. A. Demko, U. K. Traegner, G. L. Morrison, and S. R. Sobolik. "Prediction of Incompressible Flow in Labyrinth Seals." Journal of Fluids Engineering 108, no. 1 (March 1, 1986): 19–25. http://dx.doi.org/10.1115/1.3242535.

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A new approach was developed and tested for alleviating the substantial convergence difficulty which results from implementation of the QUICK differencing scheme into a TEACH-type computer code. It is relatively simple, and the resulting CPU time and number of numerical iterations required to obtain a solution compare favorably with a previously recommended method. This approach has been employed in developing a computer code for calculating the pressure drop for a specified incompressible flow leakage rate in a labyrinth seal. The numerical model is widely applicable and does not require an estimate of the kinetic energy carry-over coefficient for example, whose value is often uncertain. Good agreement with measurements is demonstrated for both straight-through and stepped labyrinths. These new detailed results are examined, and several suggestions are offered for the advancement of simple analytical leakage as well as rotordynamic stability models.
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16

Laos, Hector E., John M. Vance, and Steven E. Buchanan. "Hybrid Brush Pocket Damper Seals for Turbomachinery." Journal of Engineering for Gas Turbines and Power 122, no. 2 (January 3, 2000): 330–36. http://dx.doi.org/10.1115/1.483211.

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Pocket damper seals perform a dual function: both sealing the pressurized gas around a rotating shaft and providing large amounts of vibration damping. The annular cavity between the labyrinth seal teeth is subdivided into separate annular cavities around the circumference of the rotor by partitioning walls. Also, the upstream and downstream teeth have different radial clearances to the rotor. These seals have been shown to provide a remarkable amount of direct damping to attenuate vibration in turbomachinery, but they generally leak more than conventional labyrinth seals if both seals have the same minimum clearance. Conversely, brush seals allow less than half the leakage of labyrinth seals, but published test results show no significant amount of damping. They are considered to be a primary choice for the seals in new aircraft engine designs because of their low leakage. This paper will describe a recently invented hybrid brush/pocket damper seal that combines high damping with low leakage. Previous brush seal results were studied and calculations were made to select a brush seal to combine with the pocket damper design. The result is a hybrid seal with high damping and low leakage. A special design feature can also allow active vibration control as a bonus benefit. A computer code written for the original pocket damper seal was modified to include the brush element at the exit blade. Results from the computer code indicate that the hybrid seal can have less leakage than a six bladed (or 6 knives) labyrinth seal along with orders of magnitude more damping. Experimental evaluations of the damping and leakage performance of the hybrid seal are being conducted by the authors. The experimental work reported here tested the damping capability of the new hybrid brush seal by exciting the seal journal through an impedance head. A conventional six-bladed labyrinth seal of the same working dimensions was also tested. The brush hybrid pocket damper seal is found to leak less than the labyrinth seal while producing two to three times more damping than the original pocket damper seal (orders of magnitude more than the conventional labyrinth). [S0742-4795(00)01102-9]
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17

Zhu, Yuming, Yuyan Jiang, Shiqiang Liang, Chaohong Guo, Yongxian Guo, and Haofei Cai. "One-Dimensional Computation Method of Supercritical CO2 Labyrinth Seal." Applied Sciences 10, no. 17 (August 20, 2020): 5771. http://dx.doi.org/10.3390/app10175771.

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An actual one-dimensional(1-D) computation method for a labyrinth seal is proposed. Relevant computation hypotheses for the 1-D method are analyzed and the specificity of internal flow in an SCO2 (supercritical CO2) labyrinth seal is explored in advance. Then, the experimental correlation discharge coefficient and the residual kinetic energy coefficient used in SCO2 labyrinth seals are proposed. In addition, the speed of sound in two-phase flow is corrected in the 1-D method. All recent experimental results of the SCO2 labyrinth seal are sorted out and the latest experimental results of a stepped-staggered labyrinth seal are proposed to verify the accuracy and applicability of the 1-D method. Finally, the sealing efficiency of the SCO2 labyrinth seals are analyzed using the 1-D method.
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18

Жинов, Andrey A., and Denis V. Shevelev. "Determination of steam leaks through faulty labyrinth seals of a steam turbine." Izvestiya MGTU MAMI 16, no. 1 (November 2, 2022): 21–28. http://dx.doi.org/10.17816/2074-0530-104581.

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BACKGROUND: When calculating the axial force acting on the thrust bearing of a steam turbine, when calculating the dimensions of the unloading piston, when calculating the efficiency of the turbine stages, it is necessary to determine the amount of steam leakage through its diaphragm and end seals. Existing methods make it possible to calculate leaks only through serviceable, undamaged labyrinth seals of several standard designs. However, during the operation of steam turbines, due to off-design axial and radial displacements of the rotor, labyrinth seals are often damaged - deformed, crushed or broken. AIMS: The purpose of the study is to develop a method for calculating leaks using direct CFD modeling in serviceable and damaged seals with typical failures, verify the simulation results by comparison with known methods and experimental data, and determine critical steam leaks through faulty labyrinth turbine seals. MATERIALS AND METHODS: A method for calculating the steam flow rate through serviceable and faulty labyrinth seals of a steam turbine using the capabilities of modern CFD methods is proposed and verified. The computational domain of modeling the front-end seal of the turbine, the features of setting the boundary conditions, the adaptive computational grid, and the numerical mathematical model used are described. RESULTS: The results of a numerical study of steam leakage through serviceable and damaged labyrinth end seals of the turbine are presented: with bent ridges in the seals, with partial or complete absence of ridges. The operation of the front-end seal of the turbine was simulated with several typical failures. It is shown that partial damage to the ridges of the front-end seal of the turbine, which is often encountered during operation, leads to a significant increase in steam leakage. It has been established that with significant damage to the ridges, an increase in steam leakage can lead to the exhaustion of the capacity of the steam pressure regulator in the seal, which leads to a malfunction of the turbine thrust bearing unloading system. CONCLUSIONS: The proposed technique and the results obtained can be used to calculate steam leakage through serviceable and faulty diaphragm and end labyrinth seals of turbines, when calculating the value of the axial force acting on the turbine thrust bearing in variable operating modes, the technique is useful in assessing the efficiency of the thrust bearing unloading system.
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19

Hirano, Toshio, Zenglin Guo, and R. Gordon Kirk. "Application of Computational Fluid Dynamics Analysis for Rotating Machinery—Part II: Labyrinth Seal Analysis." Journal of Engineering for Gas Turbines and Power 127, no. 4 (September 20, 2005): 820–26. http://dx.doi.org/10.1115/1.1808426.

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Labyrinth seals are used in various kinds of turbo machines to reduce internal leakage flow. The working fluid, or the gas passing through the rotor shaft labyrinth seals, often generates driving force components that may increase the unstable vibration of the rotor. It is important to know the accurate rotordynamic force components for predicting the instability of the rotor-bearing-seal system. The major goals of this research were to calculate the rotordynamic force of a labyrinth seals utilizing a commercial CFD program and to further compare those results to an existing bulk flow computer program currently used by major US machinery manufacturers. The labyrinth seals of a steam turbine and a compressor eye seal are taken as objects of analysis. For each case, a 3D model with eccentric rotor was solved to obtain the rotordynamic force components. The leakage flow and rotor dynamics force predicted by CFX TASCFlow are compared with the results of the existing bulk flow analysis program DYNLAB. The results show that the bulk flow program gives a pessimistic prediction of the destabilizing forces for the conditions under investigation. Further research work will be required to fully understand the complex leakage flows in turbo machinery.
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20

Aslan-zada, Farhad E., Vugar A. Mammadov, and Fadi Dohnal. "Brush seals and labyrinth seals in gas turbine applications." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 227, no. 2 (November 9, 2012): 216–30. http://dx.doi.org/10.1177/0957650912464922.

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21

KANEMITSU, Yoichi, Masaru OHSAWA, and Nobuyuki KUJI. "Cross-coupled aerodynamic forces on a whirling rotor of labyrinth seals. Straight-type labyrinth seals." Transactions of the Japan Society of Mechanical Engineers Series C 51, no. 472 (1985): 3407–12. http://dx.doi.org/10.1299/kikaic.51.3407.

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22

Čížek, Michal, Vojtěch Klír, Pavel Steinbauer, and Tomáš Vampola. "LABYRINTH SEAL CFD CALCULATION AND TEMPERATURE MEASUREMENT INVESTIGATION." Aviation 26, no. 2 (June 1, 2022): 96–103. http://dx.doi.org/10.3846/aviation.2022.16886.

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This article presents currently obtained results from CFD analysis of the labyrinth seals of an aircraft turbine engine. The process of describing a geometry, grid for numerical calculation and boundary conditions are described. Numerical simulations were performed for the assumed boundary conditions. The presented results show total temperature differences in labyrinth seals compared to published results. An experimental verification of the CFD analysis was also performed to clarify the numerical simulation results. It was based on the labyrinth seal measurement stand. The final part of this study is dedicated to the discussion and the following possible activities on this topic.
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23

Vance, J. M., and J. Li. "Test Results of a New Damper Seal for Vibration Reduction in Turbomachinery." Journal of Engineering for Gas Turbines and Power 118, no. 4 (October 1, 1996): 843–46. http://dx.doi.org/10.1115/1.2817004.

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A new type of labyrinth gas seal for damping vibration and whirl, called the TAMSEAL, has been evaluated in both nonrotating and rotating tests at Texas A&M University. Test results of the prototype, along with comparison tests of a conventional labyrinth seal, show up to 100 times more direct damping than the conventional bladed seal. The new design also has a feature that blocks swirl of the working fluid, which is known to be rotordynamically destabilizing in machines with conventional seals. Coastdown tests of the new seal were conducted at various pressures on a rotordynamic test apparatus with a critical speed at 4000 rpm and compared with identical testing of a conventional labyrinth seal. Rap tests of both seals were also conducted to measure the logarithmic decrement of free vibration, and the leakage of both seals was measured. Test results show large reductions in peak vibration at the critical speed in all cases, with the critical speed being completely eliminated by the TAMSEAL at some pressure drop conditions. The leakage rate of the tested TAMSEAL is higher than the conventional seal at the same clearance, but the large reductions in vibration and whirl amplitudes suggest that the TAMSEAL could be operated with smaller clearances than conventional labyrinth seals.
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24

Wittig, S., K. Jacobsen, U. Schelling, and S. Kim. "Heat Transfer in Stepped Labyrinth Seals." Journal of Engineering for Gas Turbines and Power 110, no. 1 (January 1, 1988): 63–69. http://dx.doi.org/10.1115/1.3240088.

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Leakage flow and heat transfer of scaled-up stepped labyrinth seals were investigated experimentally and numerically. The experiments were conducted in a test rig under steady conditions. For different geometries and pressure ratios a finite element program was used to determine the temperature distribution and subsequently the heat transfer coefficients. In verifying the experimental results, the flow field of the seals was calculated numerically by a finite difference program. Heat transfer coefficients were derived utilizing the well-known analogies between heat transfer and wall friction.
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25

Bosch, Florian, and Werner Haas. "Re-lubricating grease-filled labyrinth seals." Sealing Technology 2017, no. 6 (June 2017): 6–12. http://dx.doi.org/10.1016/s1350-4789(17)30195-2.

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26

Eser, Dursun, and Yilmaz Dereli. "Rotordynamic coefficients in staggered labyrinth seals." KSME International Journal 18, no. 5 (May 2004): 830–37. http://dx.doi.org/10.1007/bf02990302.

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27

Eser, Dursun. "Rotordynamic coefficients in stepped labyrinth seals." Computer Methods in Applied Mechanics and Engineering 191, no. 29-30 (May 2002): 3127–35. http://dx.doi.org/10.1016/s0045-7825(02)00238-4.

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28

Ilieva, G., and C. Pirovsky. "Labyrinth seals with application to turbomachinery." Materialwissenschaft und Werkstofftechnik 50, no. 5 (May 2019): 479–91. http://dx.doi.org/10.1002/mawe.201900004.

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29

Shevchenko, Serhii. "ANALYSIS OF THE IMPACT OF SPECIAL CONSTRUCTIONS OF GAP SEALS ON THE DYNAMICS OF CENTRIFUGAL MACHINES." ScienceRise, no. 5 (November 11, 2020): 3–13. http://dx.doi.org/10.21303/2313-8416.2020.001485.

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The object of research: the influence of the design features of special gap seals on the dynamic characteristics of centrifugal machines. Investigated problem: harmonization of the consumption and dynamic characteristics of the seals of the rotors of high-speed machines by applying special design methods. Main scientific results: The mechanism and operating conditions of seals with floating rings are described. It is determined that the most effective from the point of view of dynamic characteristics is the variant of the semi-movable ring. Expressions for determining the conditions of angular and radial immobility of a floating ring are obtained. The design options for deformable gap seals, including deformable floating rings, deformable interwheel seals and seals with an axially movable deformable sleeve, have been investigated. The scope of their application for unique machines with high requirements for tightness and vibration reliability has been determined. Variants of the design of labyrinth seals have been investigated. The analysis shows that the dynamic properties of labyrinth seals significantly depend on the relative position of the ridges. Overlapping ridged seals have the worst dynamic performance of the labyrinth seal designs. The honeycomb seal has more favorable dynamic properties, and the well seal has the best combination of consumption and dynamic characteristics. The dynamic characteristics are especially important for the seals of high-speed rotors of centrifugal machines. The area of practical use of the research results: Enterprises that manufacture centrifugal machines: pumps and compressors. Innovative technological product: a methodology for the selection, design and calculation of special designs of gap seals with optimization of dynamic and flow characteristics. Scope of application of the innovative technological product: The obtained research results will be useful in the design and manufacture of centrifugal pumps and compressors for any parameters.
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30

Scharrer, J. K. "Rotordynamic Coefficients for Stepped Labyrinth Gas Seals." Journal of Tribology 111, no. 1 (January 1, 1989): 101–7. http://dx.doi.org/10.1115/1.3261858.

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The basic equations are derived for compressible flow in a stepped labyrinth gas seal. The flow is assumed to be completely turbulent in the circumferential direction where the friction factor is determined by the Blasius relation. Linearized zeroth and first-order perturbation equations are developed for small motion about a centered position by an expansion in the eccentricity ratio. The zeroth-order pressure distribution is found by satisfying the leakage equation while the circumferential velocity distribution is determined by satisfying the momentum equations. The first order equations are solved by a separation of variables solution. Integration of the resultant pressure distribution along and around the seal defines the reaction force developed by the seal and the corresponding dynamic coefficients. The results of this analysis are presented in the form of a parametric study, since there are no known experimental data for the rotordynamic coefficients of stepped labyrinth gas seals. The parametric study investigates the relative rotordynamic stability of convergent, straight and divergent stepped labyrinth gas seals. The results show that, generally, the divergent seal is more stable, rotordynamically, than the straight or convergent seals. The results also show that the teeth-on-stator seals are not always more stable, rotordynamically, then the teeth-on-rotor seals as was shown by experiment by Childs and Scharrer (1986b) for a 15 tooth seal.
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31

Kwanka, Klaus. "Dynamic Coefficients of Stepped Labyrinth Gas Seals." Journal of Engineering for Gas Turbines and Power 122, no. 3 (May 15, 2000): 473–77. http://dx.doi.org/10.1115/1.1287033.

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Rotor-fluid interactions can cause self-excited shaft vibrations of high density turbomachinery. Often the amplitude of the vibrations reaches unacceptably high amplitudes and the scheduled power or running speed cannot be achieved. One of the most important sources of excitation is the flow through labyrinth seals. For a reliable design it is necessary to predict these forces exactly, including not only stiffness but also damping coefficients. As the forces in labyrinth gas seals are rather small only minimal experimental data is available for the comparison and validation of calculations. Meanwhile a new and easy-to-handle identification procedure enables the investigation of numerous seal geometrys. The paper presents dynamic coefficients obtained with a stepped labyrinth and the comparison with other seal concepts. [S0742-4795(00)00903-0]
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32

Joachimiak, Damian. "Method for the reduction of leakage in labyrinth seals by adapting the seal geometry to match the flow conditions." E3S Web of Conferences 323 (2021): 00014. http://dx.doi.org/10.1051/e3sconf/202132300014.

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In this paper a method for reducing leakage in labyrinth seals is presented. This method is based on CFD calculations and consists in the analysis of the phenomenon of gas kinetic energy carry-over in chambers of the seal between gaps. It belongs to the group of geometrical inverse problems and is designed for seals of given outside dimensions. For straight through labyrinth seals it enables determining the number of teeth and their optimal arrangement. This method was developed based on numerical and experimental tests. Examples of numerical calculations presented in this paper prove that this method is effective for straight through seals. We obtained the reduction of leakage ranging from 8.7 to 9.4% relative to the initial geometry with no change in the outside dimensions of the seal.
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33

Zhuang, Qingyuan, Ronnie Bladh, Erik Munktell, and Yong Lee. "Parametric study on the aeroelastic stability of rotor seals." Journal of the Global Power and Propulsion Society 3 (May 13, 2019): 569–79. http://dx.doi.org/10.33737/jgpps/110751.

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Labyrinth seals are widely used in rotating machinery and can be prone to aeroelastic instabilities. The rapid development of computational fluid dynamics now provides a high-fidelity approach for predicting the aeroelastic behavior of labyrinth seals in three dimension and exhibits great potential within industrial application, especially during the detailed design stages. In the current publication a time-marching unsteady Reynolds-averaged Navier-Stokes solver was employed to study the various historically identified parameters that have essential influence on the stability of labyrinth seals. The findings from the numerical approach agree well with analytical criteria in determining the overall stability of the seal structure while being able to capture the acoustic behavior of the upstream or downstream large cavities and its influence on the inter-fin cavities. The high-fidelity approach provides additional insights on the effects of nodal diameter, travelling wave direction, pressure ratio, and the linearity of the phenomenon for relatively large vibration amplitudes, all of which can aid during the design space exploration.
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34

Kleffel, Tobias, Philipp Frey, Marion Merklein, and Dietmar Drummer. "Analysis of the formation of gap-based leakages in polymer-metal electronic systems with labyrinth seals." Journal of Polymer Engineering 39, no. 6 (July 26, 2019): 573–86. http://dx.doi.org/10.1515/polyeng-2019-0098.

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Abstract A major challenge in manufacturing polymer-metal electronic systems, for example, encapsulations of metal inserts using assembly injection molding, is to create a tight sealing in order to prevent leakage. One typical reason for leakage is the formation of gaps between polymer and metal. Through labyrinth seals, which can be manufactured by structuring of the metal surface, the gap-based leakage networks can be interrupted. However, in order to use the appropriate structure in the right position, knowledge about the formation of the gaps is essential. The research covered in this paper focuses on the analysis of the formation of gap-based leakages in polymer-metal electronic systems with labyrinth seals to improve the component design of such parts. The effects of different embossed labyrinth seals, which differ in depth and features, and an electrochemically manufactured areal seal on the tightness and leakage position are investigated. Furthermore, the formation of the leakage network is presented for the investigated variants.
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35

Kaszowski, Paweł, Marek Dzida, and Piotr Krzyślak. "Calculations of labyrinth seals with and without diagnostic extraction in fluid-flow machines." Polish Maritime Research 20, no. 4 (December 1, 2013): 34–38. http://dx.doi.org/10.2478/pomr-2013-0038.

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ABSTRACT Labyrinth seals are essential components of steam turbine unit constructions. Two types of labyrinth seals can be named, the first of which is the seal without diagnostic steam extraction, and the second - with extraction. The distribution of flow parameters along the packing is affected remarkably by the average seal clearance. The presence of diagnostic extraction leads to the equation system which is determinable and can be inversed to calculate the average seal clearance Si. Analysing the obtained results leads to the conclusion that the information about this parameter provides opportunities to monitor the current state of the packing in real time. The applied calculation procedure bases on the de Saint - Venant equation. The article also includes a brief description of both types of seals.
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36

Ma, Dengqian, Jun Li, Yuanqiao Zhang, Zhigang Li, Xin Yan, and Liming Song. "Application of blade tip shroud brush seal to improve the aerodynamic performance of turbine stage." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 6 (October 22, 2019): 777–94. http://dx.doi.org/10.1177/0957650919883153.

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The blade tip shroud brush seal is applied to replace the labyrinth seal for the aerodynamic performance improvement of turbine stage. The leakage flow characteristics of the brush seal are numerically predicted by using the Reynolds-Averaged Navier–Stokes equations and non-linear Darcian porous medium model. The numerical leakage flow rate of the brush seal is in well agreement with the experimental data. The last and first long teeth of the labyrinth seal were designed to bristle pack named as the postposed and preposed brush seals based on the 1.5 turbine stage. The leakage flow rate and aerodynamic performance of the turbine stage with blade tip shroud labyrinth seal and brush seal are numerically investigated. The effect of the sealing clearance between bristle pack and tip shroud on the aerodynamic performance of turbine stage is conducted which ranged from 0 mm to 0.4 mm. The axial deflection of the bristle pack is analyzed with consideration of the aerodynamic forces and contact frictional force. The obtained results show that the leakage flow rate of the tip shroud brush seals with bristle tip 0.4 mm clearance which decreases by up to 18% in comparison with the labyrinth seal, and the aerodynamic efficiency increases by 0.6%. Compared to the tip labyrinth seal, tip shroud brush seals can decrease the relative deflection angle of exit flow. This flow behavior results in reducing the mixing loss between the tip leakage flow and mainstream. The similar axial deflection of the bristle pack for two kinds of brush seals is observed at the same sealing clearance. The deflection of the bristle pack under the function of the aerodynamic forces is protected by the backing plate. This work provides the theoretical basis and technical support for the brush seal application in the turbine industries.
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37

Krzyślak, Piotr, and Marian Winowiecki. "A method of diagnosing labyrinth seals in fluid-flow machines." Polish Maritime Research 15, no. 3 (October 1, 2008): 38–41. http://dx.doi.org/10.2478/v10012-007-0081-2.

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A method of diagnosing labyrinth seals in fluid-flow machines Steam turbines constitute fluid flow machines which are used for driving engines of power plants, merchant and naval ships. They are commonly applied in power industry to driving electric generators. One of the impotant elements which affect efficiency of steam turbines used in power industry and for ship propulsion is state of labyrinth sealings whose aim is to minimize losses associated with steam leakage within turbine casing. Until now to assess state of labyrinth sealings has been only possible after stopping the turbine and its dismantling in order to determine values of clearances in the sealings. This paper presents a method which makes it possible to assess state of labyrinth sealings without the necessity of stopping and dismantling the machine. This is the method which allows to assess on-line state of machine sealings during its operation.
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38

Hawkins, Larry, Dara Childs, and Keith Hale. "Experimental Results for Labyrinth Gas Seals With Honeycomb Stators: Comparisons to Smooth-Stator Seals and Theoretical Predictions." Journal of Tribology 111, no. 1 (January 1, 1989): 161–68. http://dx.doi.org/10.1115/1.3261867.

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Experimental measurements are presented for the rotordynamic stiffness and damping coefficients of a teeth-on-rotor labyrinth seal with a honeycomb stator. Inlet circumferential velocity, inlet pressure, rotor speed, and seal clearance are primary variables. Results are compared to (a) data for teeth-on-rotor labyrinth seals with smooth stators, and (b) analytical predictions from a two-control-volume compressible flow model. The experimental results show that the honeycomb-stator configuration is more stable than the smooth-stator configuration at low rotor speeds. At high rotor speeds, the stator surface does not affect stability. The theoretical model predicts the cross-coupled stiffness of the honeycomb-stator seal correctly within 25 percent of measured values. The model provides accurate predictions of direct damping for large clearance seals; however, the model predictions and test results diverge with increasing running speed. Overall, the model does not perform as well for low clearance seals as for high clearance seals.
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39

Gautam, Saroj, Nirmal Acharya, Sailesh Chitrakar, Hari Prasad Neopane, Igor Iliev, and Ole Gunnar Dahlhaug. "Sediment erosion in the labyrinths of Francis turbine: A numerical study." IOP Conference Series: Earth and Environmental Science 1037, no. 1 (June 1, 2022): 012032. http://dx.doi.org/10.1088/1755-1315/1037/1/012032.

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Abstract Development of new hydropower projects in Himalayan regions aims for the efficient performance of the turbine with lesser operation and maintenance cost. Over the past two decades, significant efforts have been made to improve the sediment handling capabilities by the turbine components. In the case of Francis turbines, the design of guide vanes and runner blades were focused on the past to improve the sediment resistivity. However, other components of these machines were not studied from the perspective of sediment erosion. The present work aims to study the sediment erosion in the labyrinth sealings of a prototype Francis turbine, having serious erosion problems. Upper labyrinth sealing and bottom labyrinth sealing were modelled by developing a reference case and the erosion wear in these regions were examined numerically. The flow leaving the gap between stationary guide vanes and the runner enters the top and bottom labyrinth seals. While sediment flows along with the clean water these seals get heavily eroded. The results from the numerical investigation show a distinct pattern of erosion locations in the labyrinth sealings that is similar to the field observation.
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40

Fürst, Jiří. "Numerical Simulation of Flows through Labyrinth Seals." Applied Mechanics and Materials 821 (January 2016): 16–22. http://dx.doi.org/10.4028/www.scientific.net/amm.821.16.

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A numerical code for calculation of leakage flowand rotordynamic coefficients of labyrinth seals has beendeveloped. The code is based on the solution of Reynolds-averagedNavier-Stokes equations combined with a two-equation turbulencemodel. The numerical solution is achieved with finite volume methodand the rotordynamic coefficients are evaluated from severalsimulations with different rotor precessions. The solution iscompared to single control volume based bulk flow method[Williams, 1998] and to the experimental results for look-throughlabyrinth seal [Schettel, 2004].
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41

MIYAKE, Kunihiro, and Ichiro ARIGA. "Leakage Characteristics of Rotating Stepped Labyrinth Seals." Transactions of the Japan Society of Mechanical Engineers Series B 51, no. 466 (1985): 1975–80. http://dx.doi.org/10.1299/kikaib.51.1975.

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42

Kostyuk, A. G. "Selection of labyrinth seals in steam turbines." Thermal Engineering 62, no. 1 (December 17, 2014): 14–18. http://dx.doi.org/10.1134/s0040601515010061.

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43

Kwanka, K. "Improving the Stability of Labyrinth Gas Seals." Journal of Engineering for Gas Turbines and Power 123, no. 2 (March 1, 1997): 383–87. http://dx.doi.org/10.1115/1.1359772.

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The flow through labyrinth seals of turbomachinery generates forces which can cause self-excited vibrations of the rotor above the stability limit. The stability limit is reached at a specific rotating speed or power. The continuous growth of power density and rotating speed necessitates an exact prediction of the stability limit of turbomachinery. Usually the seal forces are described with dynamic coefficients. A new, easy-to-handle identification procedure uses the stability behavior of a flexible rotor to determine the dynamic coefficients. Systematic measurements with a great number of labyrinth seal geometries lead to reasonable results and demonstrate the accuracy and sensitivity of the procedure. A comparison of the various methods used to minimize the excitation indicates which seal is more stable and will thus improve the dynamic behavior of the rotor.
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44

Chegurko, L. E. "Investigation of labyrinth-screw and screw seals." Chemical and Petroleum Engineering 21, no. 4 (April 1985): 166–69. http://dx.doi.org/10.1007/bf01148097.

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45

Eser, Dursun, and Jacob Y. Kazakia. "Air flow in cavities of labyrinth seals." International Journal of Engineering Science 33, no. 15 (December 1995): 2309–26. http://dx.doi.org/10.1016/0020-7225(95)00072-6.

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46

Ransom, David, Jiming Li, Luis San Andre´s, and John Vance. "Experimental Force Coefficients for a Two-Bladed Labyrinth Seal and a Four-Pocket Damper Seal." Journal of Tribology 121, no. 2 (April 1, 1999): 370–76. http://dx.doi.org/10.1115/1.2833949.

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Experiments are presented to identify the stiffness and damping force coefficients of a two-blade, teeth on stator labyrinth seal with diverging clearance and its modified version as a four-pocket gas damper seal. The seals were tested without journal rotation and at rotor speeds of 1500 rpm and 3000 rpm for seal supply to ambient pressure ratios ranging from 1 to 3. Calibrated impact loads excite a flexibly supported housing holding rigidly the test seal. The impact loads and seal displacement and acceleration time responses are measured and recorded as frequency spectra. The instrumental variable filter method is used to identify the seal dynamic force coefficients from the measured transfer functions over a frequency range. The experiments demonstrate the four pocket gas damper seal has large (positive) direct damping coefficients and relatively small (negative) direct stiffness coefficients. The two bladed labyrinth seal exhibits positive direct stiffness and negative damping force coefficients. The leakage performance of both seals is nearly identical. The four pocket damper seal clearly outperforms the labyrinth seal in terms of rotordynamic forces. Both seals show a minimal amount of cross-coupling force effects, well within the experimental uncertainty.
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47

Zhao, Yizhen, and Chunhua Wang. "Shape Optimization of Labyrinth Seals to Improve Sealing Performance." Aerospace 8, no. 4 (April 1, 2021): 92. http://dx.doi.org/10.3390/aerospace8040092.

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To reduce gas leakage, shape optimization of a straight labyrinth seal was carried out. The six design parameters included seal clearance, fin width, fin height, fin pitch, fin backward, and forward expansion angle. The CFD (Computational Fluid Dynamics) model was solved to generate the training and testing samples for the surrogate model, which was established by the least square support vector machine. A kind of chaotic optimization algorithm was used to determine the optimal design parameters of the labyrinth seal. As seal clearance, fin width, fin height, fin pitch, fin backward and forward expansion angles are 0.2 mm, 0.1 mm, 7 mm, 9 mm, 0°, and 15°, the discharge coefficient can reach its minimum value in the design space. The chaotic optimization algorithm coupled with least square support vector machine is a promising scheme for labyrinth seal optimization.
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48

Jahn, Ingo HJ. "Design approach for maximising contacting filament seal performance retention." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 5 (June 27, 2014): 926–42. http://dx.doi.org/10.1177/0954406214541433.

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Good sealing is a key requirement for modern efficient turbomachinery such as steam and gas turbines. A class of seals that promise better performance, compared to conventional labyrinth seals, are contacting filament seals such as brush, leaf, or finger seal. When new, these filament seals offer better performance; however, if poorly designed they wear excessively, resulting in leakages higher than a comparable labyrinth seal. This paper outlines a design methodology for selecting ideal contacting filament seal properties for a given operating cycle or set of operating cycles. Following this approach ensures the seal performs well, the seal retains its performance, and performance is retained if the operating cycle is altered. In the approach, the seals are described by four generic properties (stiffness, blow-down, cross-coupling, and build clearance), which are then used for a performance evaluation based on a number of test cycles. Once the ideal seal properties for a given operating cycle have been identified, a seal to match these can be designed. The approach is evaluated with a generic gas turbine cycle and recommendations for ideal contacting filament seal properties for this cycle are made.
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49

Liu, Zhen Ping, Shu Lian Liu, and Shui Ying Zheng. "A New Method to Realize Unsteady Calculation of Flow in Labyrinth Seals." Advanced Materials Research 199-200 (February 2011): 68–71. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.68.

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As non-contact seal, labyrinth seal is widely used in rotor system of high speed. However, with the development of turbo-machinery toward high performance and huge capacity, gas excitation vibration within the labyrinth seal becomes the main reason threatening safe operating of machinery sets. Recently three dimensional computational fluid dynamic was applied to analyse inside flow in labyrinth seal. These researches, while greatly improve rotordynamic prediction of labyrinth seals, are mostly focused in steady calculation. In fact, rotor inside the seal is whirling in a nonlinear behaviour, which makes the flow unstable. In an effort to analyse the non-linear behaviour of flow in labyrinth seal, this paper utilizes an improved dynamic mesh technology to realize unsteady calculation. The Reynolds Averaged Navier Stokes equations is solved by a commercial CFD program, FLUENT. Steady calculations are firstly done to determine mesh density and turbulence model, then an unsteady analysis is used to study gas excitation force. The influence of initial condition to the unsteady analysis is discussed. This method allows modeling of rotor orbit around the eccentric position and gives prediction of nolinear gas excitation force.
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50

Kim, N., S. Y. Park, and D. L. Rhode. "Predicted Effects of Shunt Injection on the Rotordynamics of Gas Labyrinth Seals." Journal of Engineering for Gas Turbines and Power 125, no. 1 (December 27, 2002): 167–74. http://dx.doi.org/10.1115/1.1520539.

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A recent CFD perturbation model for turbomachinery seal rotordynamics was extended for labyrinth shunt injection with an arbitrarily high pressure gas. A large number of measured cases with labyrinth injection pressure at approximately 13.8 bars (200 psi) were computed and compared with measurements. The drastically reduced (negative) cross-coupled stiffness, which is the primary advantage from the use of shunt injection in gas labyrinth seal applications, was well predicted. The agreement with measurements for k, C, and Ceff was within about 40%, 60% and 10%, respectively. In addition, it was found that moving the injection toward the high pressure end of the seal gives k, C, and Ceff values that are rotordynamically only slightly more stabilizing. Further, the radial distributions of the flow perturbation quantities give support to the two-control volume approach for developing bulk-flow models for labyrinth seal rotordynamics.
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