Academic literature on the topic 'Direct-flow and axial-radial seal'
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Journal articles on the topic "Direct-flow and axial-radial seal"
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Daniels, W. A., B. V. Johnson, D. J. Graber, and R. J. Martin. "Rim Seal Experiments and Analysis for Turbine Applications." Journal of Turbomachinery 114, no. 2 (April 1, 1992): 426–32. http://dx.doi.org/10.1115/1.2929161.
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An experimental investigation was conducted to determine the sealing effectiveness and the aerodynamic characteristics of four rim seal models for a number of flow conditions. The experiments were conducted to obtain an extended data base for advanced turbine rim seal design. The class of rim seals investigated are those found on the downstream side of the rotor where the boundary layer on the disk is pumped directly into the seal gap. The experiments were conducted at disk tangential Reynolds numbers up to 5.1 × 106 with a simulated gas path flow across the top of the seal. The simulated gas path flow was injected with various amounts of swirl to determine the effect of swirl on the seal effectiveness. The radial gap and the axial overlap of the seal were varied and results compared with a baseline configuration. A rim seal configuration intended to prevent disk pumping directly into the seal gap was also investigated. A mass transfer analogy was used to characterize the rim seal ingestion characteristics and the trace gas chosen for this technique was CO2. The results of this investigation indicate that decreasing the radial gap of the seal produces a better improvement in seal effectiveness than increasing the axial overlap of the seal, that seal effectiveness increases only modestly as the swirl across the top of the seal decreases, and that the trace gas technique employed to determine seal effectiveness is an accurate alternative to pressure measurement or flow visualization techniques used by other investigators. The results of this investigation were compared with results from a boundary layer model for rim seals with axial gap geometries.
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Sun, Dan, Yan Ting Ai, Wan Fu Zhang, and Jian Gang Yang. "Design of a New Kind of the Radial Annular Seal for the Aeroengine." Advanced Materials Research 621 (December 2012): 326–29. http://dx.doi.org/10.4028/www.scientific.net/amr.621.326.
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To minimize fluid leakage loss and improve rotordynamic stability of traditional aeroengine seals, a new kind of radial annular rim seal (RARS) is presented in this paper. Comparing with the conventional labyrinth rim seal (LRS), the fluid leakage direction is modified from the axial to radial direction. The flow resistance increases, and the flow-induced force is greatly reduced. The completed three-dimensional CFD model between RARS and LRS were employed to analyze the inherent characteristics of the fluid flow in the whole passage. Calculated results show that RARS has less leakage and fluid-induced force compared to the LRS.
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Kirk, R. Gordon. "A Method for Calculating Labyrinth Seal Inlet Swirl Velocity." Journal of Vibration and Acoustics 112, no. 3 (July 1, 1990): 380–83. http://dx.doi.org/10.1115/1.2930519.
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The results of numerous investigators have shown the importance of inlet swirl on the calculated dynamic stiffness and stability of labyrinth seals. These results have not included any calculation of inlet leakage of swirl as a function of complex disk geometry including the sealing conditions of the given seal. This paper outlines a method of calculating the inlet swirl at the entrance of the labyrinth seal by introducing a radial chamber which when added to the axial flow solution allows the prediction of the gas swirl as it flows radially from the stage tip along the disk face inward to the seal location. This solution is consistent with the leakage model for the seal and allows rapid evaluation of seal designs. For a centrifugal compressor, this added feature permits the designer to include the flow path from the impeller discharge, down the back of the disk or front of the cover, then into the shaft seal or eye packing, respectively. The solution includes the friction factors of both the disk and stationary wall with account for mass flow rate and calculation of radial pressure gradients by a free vortex solution. The results of various configurations are discussed and comparisons made to other published results of disk circumferential velocity swirl.
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Stadnik, Mykola, Serhiy Shargorodskiy, and Volodymyr Rutkevych. "ENSURING CONTINUOUS HYSTERESIS OF SPROAD ACTION VALVE SAFETY VALVES." ENGINEERING, ENERGY, TRANSPORT AIC, no. 4(111) (December 18, 2020): 100–108. http://dx.doi.org/10.37128/2520-6168-2020-4-11.
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In the article principles of construction and design of spring valve units are considered, which allow to obtain a given dynamic quality to ensure constant hysteresis of spool safety valves of direct action. The analysis of efficiency of devices of correction of dynamic quality of spring valve units for ensuring their working capacity at variation of external operating factors by purposeful management of kinematic and force parameters of elastic-damping elements, and also the reasons influencing hysteresis It is noted that one of the reasons for the increase in hysteresis is damage to the rubber seals of the spool safety valves of direct action. Identifying the main causes of damage to rubber seals: constant friction of the edge of the radial holes of the spool on the seal ring; reverse the direction of the operating pressure; the pressure drop created by the axial hole of the spool when the valve is fully open. A spool spring valve with a mechanical spring having high throughput and low hysteresis is proposed. This characteristic was achieved through the use of high quality materials, which allowed to have a high throughput with minimal dimensions; optimization of geometrical characteristics of the flowing part of the valve; reducing the seal tension and, as a consequence, reducing the hysteresis. It is noted that the absence of contact of the radial holes of the spool with the rubber seal in the extreme off position protects the seal from plastic deformation during reverse flow. The prospect of further research in obtaining experimental dependences of the influence of spool speed, rubber stiffness, geometrical characteristics of the contact gap and pressure on the change of the valve hysteresis is revealed.
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Bayley, F. J., and C. A. Long. "A Combined Experimental and Theoretical Study of Flow and Pressure Distributions in a Brush Seal." Journal of Engineering for Gas Turbines and Power 115, no. 2 (April 1, 1993): 404–10. http://dx.doi.org/10.1115/1.2906723.
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A relatively simple theory is presented that can be used to model the flow and pressure distribution in a brush seal matrix. The model assumes laminar, compressible, isothermal flow and requires knowledge of an empirical constant: the seal porosity value. Measurements of the mass flow rate together with radial and axial distributions of pressure were taken on a nonrotating experimental rig. These were obtained using a 122 mm bore brush seal with 0.25 mm radial interference. The experimental data are used to estimate the seal porosity. Measurements of the pressure distributions along the backing ring and under the bristle tips and discussed. Predicted mass flows are compared with those actually measured and there is reasonable agreement considering the limitations of the model.
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Kaneko, S. "Application of Porous Materials to Annular Plain Seals: Part 2—Dynamic Characteristics." Journal of Tribology 112, no. 4 (October 1, 1990): 624–30. http://dx.doi.org/10.1115/1.2920307.
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For improving the dynamic performance of the annular plain seals employed in pumps, porous materials are applied to the seal surface by insertion into the inlet part of the seal. The linear stiffness and damping coefficients of the seal film are calculated in the laminar-flow regime, assuming the mass effect of the fluid to be negligibly small. Numerical results show that the annular plain seals with the porous materials have larger main stiffness terms and smaller cross-coupled stiffness terms and main damping terms than the conventional ones with the solid surfaces. This tendency is more marked with increasing the axial length of the porous matrix applied to the seal surface. The larger main stiffness terms for “the porous seal” yield larger radial reaction force acting on a rotor as a consequence of small whirling motion of shaft about a centered position, which would contribute to rotor stability.
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Zhulyov, A., V. Martsinkovsky, and C. Kundera. "Analysis of Forced Spatial Vibrations of a Centrifugal Pump Impeller with Axial Forces Balancing Device." International Journal of Applied Mechanics and Engineering 21, no. 3 (August 1, 2016): 737–50. http://dx.doi.org/10.1515/ijame-2016-0043.
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Abstract In this paper, a model of a pump impeller with annular seals and a balancing device, used as a combined support-seal assembly, is considered. The forced coupled radial, angular and axial vibrations of the rotor are determined with consideration of linearized inertial, damping, gyroscopic, positional and circulating forces and moments acting on the impeller from the side of the fluid flow in annular seals. The theoretical analysis is supplemented with a numerical example, the amplitude frequency characteristics are shown.
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Arauz, Grigory L., and Luis San Andre´s. "Analysis of Two-Phase Flow in Cryogenic Damper Seals—Part II: Model Validation and Predictions." Journal of Tribology 120, no. 2 (April 1, 1998): 228–33. http://dx.doi.org/10.1115/1.2834414.
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Cryogenic fluid damper seals operating close to the liquid-vapor region (near the critical point or slightly sub-cooled) are likely to develop a two-phase flow region which affects the seal performance and reliability. An all-liquid, liquid-vapor, and all-vapor, i.e., a “continuous vaporization” bulk flow model for prediction of the seal dynamic forced response is given in Part I. The numerical method of solution of the flow equations is detailed here. Computed predictions for static seal characteristics, leakage and axial pressure drop, correlate well with existing measurements for a gaseous nitrogen seal and a liquid nitrogen seal with two-phase at the seal exit plane. The effects of two-phase flow regimes on the dynamic force coefficients and stability of an oxygen damper seal are discussed. Fluid compressibility effects, particularly for mixtures with low mass content of vapor, are of utmost importance. Under these conditions, an increase on seal direct stiffness and reduction of whirl frequency ratio are shown to occur.
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Childs, D., and F. Garcia. "Test Results for Sawtooth-Pattern Damper Seals: Leakage and Rotordynamic Coefficients." Journal of Tribology 109, no. 1 (January 1, 1987): 124–28. http://dx.doi.org/10.1115/1.3261303.
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Test results consisting of direct and transverse force coefficients are presented for eleven, sawtooth-pattern, damper-seal configurations. The designation “damper” seal refers to a seal which uses a deliberately roughened stator and smooth rotor, as suggested by von Pragenau [1], to increase the net seal damping force. The designation “sawtooth-pattern” refers to a stator-roughness pattern whose cross section normal to the axis of the seal resembles saw teeth with the teeth direction opposing fluid motion in the direction of shaft rotation. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or “dams.” Sawtooth-pattern seals had more damping than smooth seals but less than the round-hole-pattern seals tested previously. Stiffness of sawtooth and round-hole-pattern seals were comparable. Leakage of maximum-damping configurations was greater for sawtooth-pattern than for round-hole-pattern seals; both types of seals leaked substantially less than did smooth seals. If damping is sacrificed, sawtooth-pattern seals can be designed to leak less than round-hole-pattern seals.
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Dogu, Yahya. "Investigation of Brush Seal Flow Characteristics Using Bulk Porous Medium Approach." Journal of Engineering for Gas Turbines and Power 127, no. 1 (January 1, 2005): 136–44. http://dx.doi.org/10.1115/1.1808425.
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The flow behavior through a brush seal has been investigated by developing a flow analysis procedure with a porous medium approach. In order to increase the brush seal performance and use at more severe operating conditions, the complex flow in the bristle pack has become the major concern affecting seal features such as blow-down, hang-up, hysteresis, and bristle flutter. In this study, an axisymmetric CFD model is employed to calibrate anisotropic permeability coefficients for the bristle pack based on available experimental data: leakage, axial pressure on the rotor surface, and radial pressure on the backing plate. A simplified form of the force balance equation is introduced for the flow in the porous bristle pack. Different sets of permeability coefficients are defined for the fence height region below the seal backing plate and the upper region of the seal to correlate the different physical structures and behavior of these regions during operation. The upper region is subject to more stiffening due to backing plate support while the fence height region is free to spread and bend in the axial direction. It is found that flow resistance for the upper region should be 20% higher than the fence height region in order to match the experimental pressure within the bristle pack. Analysis results prove that the brush seal is well represented as a porous medium with this approach. Based on the model developed, characteristic flow and pressure fields in the entire bristle pack have been explored.
Dissertations / Theses on the topic "Direct-flow and axial-radial seal"
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Максюта, Дмитрий Игоревич. "Комбинированный метод аэродинамической оптимизации ступени осевой турбины." Thesis, НТУ "ХПИ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21648.
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Диссертация на соискание ученой степени кандидата технических наук по специальности 05.05.16 – турбомашины и турбоустановки. – Национальный технический университет "Харьковский политехнический институт", Харьков, 2016. Диссертация посвящена разработке комбинированного метода аэродинамической оптимизации ступени осевой турбины, который основываясь на поочередном решении одномерной и трехмерной задач, позволяет значительно повысить эффективность всей ступени при этом учитывая как характер течения рабочего тела в решетках, так и влияние на него протечек. На основании современной тенденций к использованию методов вычислительной аэродинамики (CFD) при оптимизации проточных частей осевых турбин и при этом задействуя как можно большее количество управляющих параметров в оптимизационном процессе, предложен комбинированный метод оптимизации. Предложенный метод использует одномерную и трехмерную оптимизацию, что позволяет существенно повышать аэродинамическую эффективность ступеней, при этом значительно экономя время, необходимое для проведения расчетов. С помощью предложенного метода оптимизации и методики расчета протечек в осерадиальном уплотнении выполнена оптимизация 3-й ступени ЦВД турбины К-540-23,5. Результаты проведенных расчетов показали, что повышение эффективности ступени на этапе одномерной оптимизации происходит за счет выбора на среднем радиусе оптимальных α1, β2, значений степени реактивности ρ и относительного шага решетки t/b. Повышение эффективности ступени на этапе трехмерной оптимизации происходит за счет: выбора оптимального значения входного геометрического угла β1г рабочего профиля, обеспечившего улучшение обтекания профиля; устранения локальных диффузорных участков в межлопаточном канале; нахождения оптимальных законов закрутки, обеспечивающих равномерное натекание потока по всей высоте рабочих лопаток. Суммарно абсолютный КПД новой ступени увеличился более чем на 1 %.Thesis for degree of Candidate of Sciences in Technique for speciality 05.05.16 – turbomachinery and turbine-installations. – National Technical University "Kharkiv Polytechnical Institute", Kharkiv, 2016. This thesis deals with the development of the combined method of aerodynamic optimization of the axial turbine stage, based on the iterative usage of one-dimensional and three-dimensional theories, thereby can significantly improve the efficiency of the entire stage taking into account the nature of the flow around turbine profiles and the impact of leakage on it. Based on current trends of using computational fluid dynamic methods (CFD) while optimizing of the flow path of the axial turbines, with engaging the largest pos-sible number of control parameters in the optimization process, the combined optimization method is provided. Developed method uses one-dimensional and three-dimensional optimization theories and can noticeably improve aerodynamic efficiency of whole turbine stage, thus significantly saving the time required for the simulations. A three-step comprehensive comparison of the results of simulations with the experimental data confirmed the accuracy of CFD usage while developing the optimization method. To calculate amount of leakage in the radial clearance during one-dimensional optimization phase more accurate, the methodology of flow rate determining in axial-radial seals depending on geometrical, operational characteristics and considering rotor against stator displacement was developed using a series of CFD simulations. Advanced CFD study was conducted to compare the axial-radial seal with the straight-flow one and to identify the new more effective designs of seal. It was shown that creation of artificial roughness on the shaft of the straight-flow seal could reduce the leakage by 45 % compared to the axial-radial seal. Utilizing the developed optimization method and the methodology of leakage calculation in the axial-radial seal, the optimization of the 3rd stage of the high pressure turbine K-540-23,5 was made. As a result of the optimization a new stage with an absolute efficiency increase more than 1 % compared to the original design was obtained.
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Максюта, Дмитро Ігорович. "Комбінований метод аеродинамічної оптимізації ступеня осьової турбіни." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/21646.
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Дисертація присвячена розробці комбінованого методу аеродінамічної оптимізації ступеня осьової турбіни, який ґрунтуючись на почерговому вирішенні одновимірної та тривимірної задач, дозволяє значно підвищити ефективність всього ступеня враховуючи як характер течії робочого тіла в решітках, так і вплив на неї витоки. На підставі сучасної тенденцій до використання методів чисельної аеродинаміки (CFD) при оптимізації проточних частин осьових турбін і при цьому задіяючи якомога більшу кількість управляючих параметрів в оптимізаційному процесі, запропонований комбінований метод оптимізації. Запропонований метод використовує одновимірну та тривимірну оптимізації, що дозволяє істотно підвищувати аеродинамічну ефективність ступенів, при цьому значно заощаджуючи час, необхідний для проведення розрахунків. При розробці методу оптимізації достовірність застосування методів CFD підтверджена шляхом триетапного порівняння результатів розрахунків з результатами експериментальних досліджень. Для отримання більш точних даних кількості витоки робочого тіла в радіальний зазор при проведенні етапу одновимірної оптимізації, розроблена методика для визначення коефіцієнта витрати вісерадіального ущільнення в залежності від його геометричних і режимних характеристик, а також з урахуванням зсуву ротора відносно статора від теплового розширення. Дана методика розроблялася шляхом проведення серії CFD розрахунків. Додатково проведено CFD дослідження для порівняння вісерадіальних ущільнень з прямоточними та виявлення нових ефективних конструкцій ущільнень, яке показало, що шляхом створення штучної шорсткості на валу прямоточного ущільнення можна зменшити витрату через нього на 45 % в порівнянні з вісерадіальними ущільненнями. За допомогою запропонованого методу оптимізації та методики розрахунку витоки в вісерадіальному ущільненні виконана оптимізація 3-го ступеня ЦВТ турбіни К-540-23,5. Результати проведених розрахунків показали, що абсолютний ККД нового ступеня збільшився більш ніж на 1 %.Thesis for degree of Candidate of Sciences in Technique for speciality 05.05.16 – turbomachinery and turbine-installations. – National Technical University "Kharkiv Polytechnical Institute", Kharkiv, 2016. This thesis deals with the development of the combined method of aerodynamic optimization of the axial turbine stage, based on the iterative usage of one-dimensional and three-dimensional theories, thereby can significantly improve the efficiency of the entire stage taking into account the nature of the flow around turbine profiles and the impact of leakage on it. Based on current trends of using computational fluid dynamic methods (CFD) while optimizing of the flow path of the axial turbines, with engaging the largest pos-sible number of control parameters in the optimization process, the combined optimization method is provided. Developed method uses one-dimensional and three-dimensional optimization theories and can noticeably improve aerodynamic efficiency of whole turbine stage, thus significantly saving the time required for the simulations. A three-step comprehensive comparison of the results of simulations with the experimental data confirmed the accuracy of CFD usage while developing the optimization method. To calculate amount of leakage in the radial clearance during one-dimensional optimization phase more accurate, the methodology of flow rate determining in axial-radial seals depending on geometrical, operational characteristics and considering rotor against stator displacement was developed using a series of CFD simulations. Advanced CFD study was conducted to compare the axial-radial seal with the straight-flow one and to identify the new more effective designs of seal. It was shown that creation of artificial roughness on the shaft of the straight-flow seal could reduce the leakage by 45 % compared to the axial-radial seal. Utilizing the developed optimization method and the methodology of leakage calculation in the axial-radial seal, the optimization of the 3rd stage of the high pressure turbine K-540-23,5 was made. As a result of the optimization a new stage with an absolute efficiency increase more than 1 % compared to the original design was obtained.
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Stieha, Joseph K. "INVESTIGATION OF AN AXIAL FLOW ROTARY VALVE SEAL." UKnowledge, 2017. https://uknowledge.uky.edu/me_etds/101.
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This thesis investigates potential materials to be used in the rotary sealing industry that provide low power loss and minimize cost. The studied rotary valve utilizes slots that act as timing valves to allow for flow axially, through the seal face, at particular times within a heat pump cycle. This investigation examines various combinations of multiple PTFE materials, plastics, and soft metals that have been proven to provide low friction coefficients. Leakage and wear requirements are stated for the future use of the rotary valve and are used to determine the effectiveness of sealing the fluid while examining the power loss. In conclusion, the study finds the combination of a modified PTFE stationary ring and Aluminum Bronze rotating face to provide the lowest power loss. Numerical analysis was completed to verify the lubrication regime to be partial lubrication and was also used to investigate geometry changes and impact on the power loss.
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Dahlqvist, Johan. "Cavity Purge Flows in High Pressure Turbines." Doctoral thesis, KTH, Kraft- och värmeteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-218468.
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Turbomachinery forms the principal prime mover in the energy and aviation industries. Due to its size, improvements to this fleet of machines have the potential of significant impact on global emissions. Due to high gas temperatures in stationary gas turbines and jet engines, areas of flow mixing and cooling are identified to benefit from continued research. Here, sensitive areas are cooled through cold air injection, but with the cost of power to compress the coolant to appropriate pressure. Further, the injection itself reduces output due to mixing losses.A turbine testing facility is center to the study, allowing measurement of cooling impact on a rotating low degree of reaction high pressure axial turbine. General performance, flow details, and cooling performance is quantified by output torque, pneumatic probes, and gas concentration measurement respectively. The methodology of simultaneously investigating the beneficial cooling and the detrimental mixing is aimed at the cavity purge flow, used to purge the wheelspace upstream of the rotor from hot main flow gas.Results show the tradeoff between turbine efficiency and cooling performance, with an efficiency penalty of 1.2 %-points for each percentage point of massflow ratio of purge. The simultaneous cooling effectiveness increase is about 40 %-points, and local impact on flow parameters downstream of the rotor is of the order of 2° altered turning and a Mach number delta of 0.01. It has also been showed that flow bypassing the rotor blading may be beneficial for cooling downstream.The results may be used to design turbines with less cooling. Detrimental effects of the remaining cooling may be minimized with the flow field knowledge. Stage performance is then optimized aerodynamically, mixing losses are reduced, and the cycle output is maximized due to the reduced compression work. The combination may be used to provide a significant benefit to the turbomachinery industry and reduced associated emissions.Strömningsmaskinen i dess olika variationer bildar den främsta drivmotorn inom kraftproduktion och flygindustrin. En förbättring av denna väldiga maskinpark har potentialen till betydande inverkan på globala utsläpp. Områden som identifierats kunna dra nytta av vidare forskning är ombandningsprocesser och kylning. Dessa områden är inneboende i stationära gasturbiner och jetmotorer på grund av de heta gaser som används. Kylning uppnås genom injektion av kall luft i kritiska områden och försäkrar därmed säker drift. Kylningen kommer dock till en kostnad. På cykelnivå krävs arbete för att komprimera flödet till korrekt tryck. Dessutom medför injektionen i sig förluster som kan härledas till omblandningsprocessen. Syftet med detta arbete är att samtidigt undersöka de fördelaktiga kylegenskaperna som nackdelarna med inblandning för att på så sätt bestämma den uppoffring som måste göras för en viss kylning. Alla förbättringar tros dock inte behöva föregås av en uppoffring. Om påverkan av kylningen på huvudflödet är välförstådd kan designen justeras för att ta hänsyn till denna förändring och minimera inverkan. Denna metodologi riktar sig mot ett särskilt kylflöde, kavitetsrensningsflödet, som har till uppgift att avlägsna het luft från den kavitet som uppkommer uppströms rotorskivan i ett högtrycksturbinsteg. Studien kretsar kring en turbinprovanläggning som möjliggör detaljerade strömningsmätningar i ett roterande turbinsteg under inverkan av kavitetsrensningsflödet. Högtrycksturbinsteget som används för undersökningen är av låg reaktionsgrad. Här kvantifieras generell prestanda genom mätning av vridmomentet på utgående axel. Flödesfältet kvantifieras med pneumatiska sonder, och kylningsprestandan predikteras genom gaskoncentrationsmätningar. Resultaten visar avvägningen och sambandet mellan turbinverkningsgrad och kylning i kavitet samt huvudkanal. Flödet mäts i detalj, och de effekter som kan förväntas uppkomma då ett turbinsteg utsätts för en viss mängd av kylflödet kvantifieras. De kvantitativa resultaten för det undersökta steget visar på en förlust i verkningsgrad på 1.2 procentenheter för varje procentenhet av kavitetsrensningsflödet i termer om massflödesförhållande. Samtidigt ses kyleffektiviteten öka med 40 procentenheter. Den lokala inverkan på flödesfältet nedströms rotorn för det undersökta steget är 2° i flödesvinken och en ändring på 0.01 i Machnummer för varje procentenhet av kylflödet. Dessa ändringar ses i form av ökad omlänkning och reducerad hastighet nära hubben, och vice versa omkring halva spännvidden. Inverkan av aktuell driftpunkt understryks genom arbetet. Det har också visats att ett läckage som kringgår rotorbladen i vissa kan fall ge fördelaktig kylning i områden nedströms. Denna kombinerade kunskap kan användas för design av turbiner med så låg mängd kylning som möjligt samtidigt som säker drift bibehålls. Den negativa inverkan av den återstående kylningen kan minimeras genom kunskapen om hur flödesfältet påverkas. Genom detta optimeras stegverkningsgraden aerodynamiskt, omblandningsförluster minimeras, och cykeleffekten maximeras genom det minskade kompressionsarbetet till följd av de reducerade kylmängderna. Kombinationen kan ge en betydande förbättring för turbinindustrin och minskade utsläpp.
QC 20171129
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Flores, Diego [Verfasser], and Jörg [Akademischer Betreuer] Seume. "Influence of labyrinth seals in cavities on the flow of an axial compressor / Diego Flores ; Betreuer: Jörg Seume." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://d-nb.info/1168379962/34.
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Flores, Galindo Diego Rodrigo [Verfasser], and Jörg [Akademischer Betreuer] Seume. "Influence of labyrinth seals in cavities on the flow of an axial compressor / Diego Flores ; Betreuer: Jörg Seume." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://nbn-resolving.de/urn:nbn:de:101:1-2018100402081060711538.
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Fiore, Maxime. "Influence of cavity flow on turbine aerodynamics." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0013/document.
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Afin de faire face aux fortes températures rencontrées par les composantsen aval de la chambre de combustion, des prélèvements d’air plus frais sont réalisésau niveau du compresseur. Cet air alimente les cavités en pied de turbine et refroidiles disques rotor permettant d’assurer le bon fonctionnement de la turbine.Ce manuscrit présente une étude numérique de l’effet de ces écoulements de cavitéau pied de la turbine sur ses performances aérodynamiques. Les phénomènesd’interaction entre l’air de cavité en pied de turbine et l’air de veine principal est unphénomène encore difficilement compris. L’étude de ces phénomènes est réalisée autravers de différentes approches numériques (RANS, LES et LES-LBM) appliquéesà deux configurations pour lesquelles des résultats expérimentaux s ont disponibles.Une première configuration en grille d’aube linéaire en amont de laquelle différentesgéométries d’entrefer (interface entre plateforme rotor et stator) et débits de cavitépouvaient être variés. Une seconde configuration annulaire composée de deux étagesde turbine comprenant les cavités en pied et plus proche d’une configuration industrielle.Les pertes additionnelles associées à l’écoulement de cavité sont mesurées etétudiées à l’aide d’une méthode basée sur l’exergie (bilans d’énergie dans l’objectifde générer du travail)In order to deal with high temperatures faced by the components downstreamof the combustion chamber, some relatively cold air is bled at the compressor.This air feeds the cavities under the turbine main annulus and cool down the rotordisks ensuring a proper and safe operation of the turbine. This thesis manuscriptintroduces a numerical study of the effect of the cavity flow close to the turbine hubon its aerodynamic performance. The interaction phenomena between the cav-ity andmain annulus flow are not currently fully understood. The study of these phenomenais performed based on different numerical approaches (RANS, LES and LES-LBM)applied to two configurations for which experimental results are avail-able. A linearcascade configuration with an upstream cavity and various rim seal geometries(interface between rotor and stator platform) and cavity flow rate avail-able. Arotating configuration that is a two stage turbine including cavities close to realisticindustrial configurations. Additional losses incurred by the cavity flow are measuredand studied using a method based on exergy (energy balance in the purpose togenerate work)
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"Experimental Study of Main Gas Ingestion in a Subscale 1.5-stage Axial Flow Air Turbine." Master's thesis, 2015. http://hdl.handle.net/2286/R.I.36468.
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abstract: Gas turbine efficiency has improved over the years due to increases in compressor
pressure ratio and turbine entry temperature (TET) of main combustion gas, made viable
through advancements in material science and cooling techniques. Ingestion of main
combustion gas into the turbine rotor-stator disk cavities can cause major damage to the
gas turbine. To counter this ingestion, rim seals are installed at the periphery of turbine
disks, and purge air extracted from the compressor discharge is supplied to the disk
cavities. Optimum usage of purge air is essential as purge air extraction imparts a penalty on turbine efficiency and specific fuel consumption.
In the present work, experiments were conducted in a newly constructed 1.5-stage
axial flow air turbine featuring vanes and blades to study main gas ingestion. The disk
cavity upstream of the rotor, the 'front cavity', features a double seal with radial clearance
and axial overlap at its rim. The disk cavity downstream of the rotor, the 'aft cavity', features a double seal at its rim but with axial gap. Both cavities contain a labyrinth seal radially inboard; this divides each disk cavity into an 'inner cavity' and a 'rim cavity'.
Time-averaged static pressure at various locations in the main gas path and disk
cavities, and tracer gas (CO2) concentration at different locations in the cavities were
measured. Three sets of experiments were carried out; each set is defined by the main air flow rate and rotor speed. Each of the three sets comprises of four different purge air flow rates, low to high.
The mass flow rate of ingested main gas into the front and aft rim cavities is
reported at the different purge air flow rates, for the three experiment sets. For the present stage configuration, it appears that some ingestion persisted into both the front and aft rim cavities even at high purge air flow rates. On the other hand, the front and aft inner cavity were completely sealed at all purge flows.Dissertation/Thesis
Masters Thesis Engineering 2015
Book chapters on the topic "Direct-flow and axial-radial seal"
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Rajesh, P., J. Sharana Basavaraja, and V. Arun Kumar. "Experimental Analysis for Leakage Flow in a Newly Designed Finger Seal with Axial Wedge." In Lecture Notes in Mechanical Engineering, 138–40. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-9949-8_27.
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Rajesh, P., J. Sharana Basavaraja, and V. Arun Kumar. "Comparison of Leakage Flow Performance Analysis of Newly Designed Finger Seal with Radial Wedge." In Lecture Notes in Mechanical Engineering, 135–37. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-16-9949-8_26.
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Anker, Jan E., Jürgen F. Mayer, and Heinz Stetter. "Computational Study of the Flow in an Axial Turbine with Emphasis on the Interaction of Labyrinth Seal Leakage Flow and Main Flow." In High Performance Computing in Science and Engineering ’01, 363–74. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-642-56034-7_35.
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Taviani, M. "Axial sedimentation of the Red Sea Transitional Region (22°–25° N): pelagic, gravity flow and sapropel deposition during the late Quaternary." In Sedimentation and Tectonics in Rift Basins Red Sea:- Gulf of Aden, 467–78. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-4930-3_25.
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Roy, Apurba Kumar, Supriyo Roy, and Kaushik Kumar. "Strategic Designing and Optimization of Mixed Flow Impeller Blades for Maritime Applications." In Handbook of Research on Military, Aeronautical, and Maritime Logistics and Operations, 470–508. IGI Global, 2016. http://dx.doi.org/10.4018/978-1-4666-9779-9.ch025.
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Mixed flow impellers are extensively used in turbomachines either to convert mechanical energy to fluid energy or to convert fluid energy to mechanical energy. According to the geometry of flow passage, turbo machines can be classified as radial, axial and mixed flow. Mixed flow turbomachines are widely used for engineering applications like cooling water duties, water intake impellers for maritime applications, flood water draining, irrigation and other application fields. The design of mixed flow impellers of high specific speed is a direct extension of the well-established methods of the designing of radial flow impellers but the introduction of near diagonal flow layout at a still larger specific speed stimulated the incorporation of axial impeller design techniques in mixed flow impeller technology. Here, an attempt has been made to design a mixed flow turbo machine blade from the basic principle of turbomachinery and fluid mechanics. On the basis of stress analysis, the blade positioning in the meridional annulus was selected and validated using artificial neural network.
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Berthier, Y., P. Jacquemard, and M. H. Meurisse. "From Phenomenology to the Concepts which flow from the Third Body. Application to Radial Face Seal." In Tribology Series, 91–102. Elsevier, 1996. http://dx.doi.org/10.1016/s0167-8922(08)70773-9.
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"*! few inches up to around 3 ft depending on the manufacturer. The impellers are of cast construction, which reduces the cost but also obviates customizing of the impeller with-out incurring added cost. Propeller mixers can be installed on a vertical centerline, on an angle off the vertical, or through the sidewall of the process vessel. Centerline installation requires the use of baffles in the vessel. Side-entering designs offer the advantage of very ef-fective pumping for low horsepower and low initial cost in large vessels over 1000 gal. However, side-entering designs must have a seal that has to contend with side loads of the candlevered shaft. This has been a problem in some critical sanitary applications. However, if the batches are very large, a side-entering prop mixer may be a logical alternative to top-centerline-installed axial- and radial-flow turbines. The most often used installation configuration is the top-entering angled method. This method produces a good circulation pattern in the process mixing tank without the." In Pharmaceutical Dosage Forms, 334. CRC Press, 1998. http://dx.doi.org/10.1201/9781420000955-38.
Full textConference papers on the topic "Direct-flow and axial-radial seal"
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Wang, Cheng-Zhang, Bruce V. Johnson, Frederick De Jong, T. K. Vashist, and Rajib Dutta. "Comparison of Flow Characteristics in Axial-Gap Seals for Close- and Wide-Spaced Turbine Stages." In ASME Turbo Expo 2007: Power for Land, Sea, and Air. ASMEDC, 2007. http://dx.doi.org/10.1115/gt2007-27909.
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3D unsteady computational fluid dynamics analyses were performed for both close-spaced and wide-spaced turbine stages with axial gap seals and a cavity. Turbine stages, with airfoil configurations similar to those previously studied at United Technologies Research Center (UTRC) and Arizona State University (ASU), were simulated for vane-blade spacing at 34 percent and 70 percent of the vane axial chord length, L. Three configurations were investigated, with the first one placing an axial gap rim seal at 17 percent L upstream of the blade for close-spaced stage, and the other two placing the axial gap seal at either 17 or 34 percent L upstream of the blade for the wide-spaced stage. The seal velocity ingestion characteristics were strongly dependent on axial location for the wide-spaced stage. The seals placed at equal distances upstream of the blade leading edge for the wide- and close-spaced stages had approximately the same average ingestion velocity characteristics. However, the ingestion velocity profiles for the wide-spaced stage were less influenced by vane wakes than for the close-spaced stage. The calculated variation of radial velocity in all gaps was consistent with previous tangential and radial velocity measurements in the seal gap measurements at the University of Aachen.
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Chen, Shuxian, Zhigang Li, Jun Li, Xin Yan, and Liming Song. "Numerical Investigations on the Sealing Effectiveness of Turbine Groove Radial Rim Seal." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-90205.
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Abstract This paper presents a numerical comparison of sealing performance between conventional radial rim seal and seven different kinds of groove radial rim seal with three coolant flow rates. Three-dimensional unsteady Reynolds-Averaged Navier-Stokes (URANS) equations, coupled with a fully developed shear stress transport (SST) turbulent model from ANSYS-CFX, are utilized to investigate the sealing effectiveness of rim seal and flow characteristics in the wheel-space cavity of gas turbines. The numerical method for the pressure distributions on the vane hub and sealing effectiveness of rim seal is validated on the basis of published experimental data. The seven kinds of groove rim seals designed in this work include four circumferential groove structures, one axial groove structure and two oblique groove structures. The sealing effectiveness of conventional and seven different groove rim seals are compared. Then the flow field in the disc cavity of conventional and groove rim seals is simulated and analyzed. Compared with conventional radial rim seal, the groove rim seals can increase the sealing effectiveness obviously. It is shown that the groove structures improve the damping dissipation of invading gas. The number of grooves has an obvious effect on sealing effectiveness of circumferential groove rim seals. The axial groove case results in less minimum sealing flow rate than oblique groove cases. In addition, the flow pattern of rim seal and disc cavity is used to describe rim seal gas ingestion flow characteristics.
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Xie, Lei, Qiang Du, Guang Liu, Zengyan Lian, and Ran Ren. "Investigation of Unsteady Flow Characteristics in Axial Rim Seal." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-58822.
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Abstract Unsteady flow structures have been observed and reported in a number of recent rim-sealing investigations. These unsteady flow structures will influence the cavity pressure distribution, therefore influence the sealing efficiency. As a result, it is important to determine the mechanisms of these unsteady flow structures and how they influence the hot gas ingestion and sealing efficiency. A two-sector axial rim seal model is used to carry out the numerical investigation. The simulation is performed using the URANS method by the commercial CFD code ANSYS CFX, in which the SST turbulent model is applied. The mechanism and influence of the unsteady flow structures are analyzed. It was found that two different types of unsteadiness are observed inside the wheel space cavity: radial large flow structures dominated by the mainstream pressure distribution and inertia wave, and circumferential Kelvin-Helmholtz vortexes induced by circumferential velocity discontinuous distribution. The number and rotating speed of the radial and circumferential flow structures can be calculated using a cross-correlation method, and it was found that they can lead to a deeper ingress. By increasing the sealing flow rate, the pressure fluctuation inside the wheel space cavity is suppressed and the rotating speed of the flow structures is deaccelerated; thus, the sealing flow stabilizes the flow inside the wheel space cavity. Meanwhile, the K-H vortices’ position is lifted by the increased sealing flow rate, and the strength of the K-H vortices is suppressed, thus the sealing efficiency inside the wheel space cavity is also improved.
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Mizuta, H., S. Nakaoka, Y. Sato, and J. Sugimura. "Simulation of Gas Transportation in Radial Shaft Seal With Model Surfaces." In STLE/ASME 2010 International Joint Tribology Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ijtc2010-41260.
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This paper describes an analytical study on gas transportation in radial shaft seal. A model is constructed in which seal surfaces with sinusoidal roughness, lubricant flow at the seal lip with gaseous cavity, dissolution of gas into and release of gas from the lubricant across double boundary films at gas-liquid interfaces, and convection of dissolved gas in the lubricant flow are considered. Polyalphaolefin as a lubricant, and helium, argon and carbon dioxide are assumed. The results demonstrate that the axial flow induced by surface roughness carries the gas, and that the gas flow through the lubricant film is proportional to the gas solubility coefficient, and the circumferential speed of the shaft, which agrees with the experimental finding for actual seals. The dependence of the gas flow on the axial flow of the oil and that on the boundary films are discussed.
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Li, Zhigang, Jun Li, Liming Song, Qing Gao, Xin Yan, and Tieyu Gao. "Effect of Outer Fin Axial Gap on the Sealing Effectiveness and Fluid Dynamics of Radial Rim Seal." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63505.
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The modern gas turbine is widely applied in the aviation propulsion and power generation. The rim seal is usually designed at the periphery of the wheel-space and prevented the hot gas ingestion in modern gas turbines. The high sealing effectiveness of rim seal can improve the aerodynamic performance of gas turbines and avoid of the disc overheating. Effect of outer fin axial gap of radial rim seal on the sealing effectiveness and fluid dynamics was numerically investigated in this work. The sealing effectiveness and fluid dynamics of radial rim seal with three different outer fin axial gaps was conducted at different coolant flow rates using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulent model solutions. The accuracy of the presented numerical approach for the prediction of the sealing performance of the turbine rim seal was demonstrated. The obtained results show that the sealing effectiveness of radial rim seal increases with increase of coolant flow rate at the fixed axial outer fin gap. The sealing effectiveness increases with decrease of the axial outer fin gap at the fixed coolant flow rate. Furthermore, at the fixed coolant flow rate, the hot gas ingestion increases with the increase of the axial outer fin gap. This flow behavior intensifies the interaction between the hot gas and coolant flow at the clearance of radial rim seal. The preswirl coefficient in the wheel-space cavity is also illustrated to analyze the flow dynamics of radial rim seal at different axial outer fin gaps.
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Da Soghe, Riccardo, Cosimo Bianchini, Carl M. Sangan, James A. Scobie, and Gary D. Lock. "Numerical Characterization of Hot Gas Ingestion Through Turbine Rim Seals." In ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/gt2016-57421.
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This paper deals with a numerical study aimed at the characterization of hot gas ingestion through turbine rim seals. The numerical campaign focused on an experimental facility which models ingress through the rim seal into the upstream wheel-space of an axial-turbine stage. Single-clearance arrangements were considered in the form of axial- and radial-seal gap configurations. With the radial-seal clearance configuration, CFD steady-state solutions were able to predict the system sealing effectiveness over a wide range of coolant mass flow rates reasonably well. The greater insight of flow field provided by the computations illustrates the thermal buffering effect when ingress occurs: for a given sealing flow rate, the effectiveness on the rotor was significantly higher than that on the stator due to the axial flow of hot gases from stator to rotor caused by pumping effects. The predicted effectiveness on the rotor was compared with a theoretical model for the thermal buffering effect showing good agreement. When the axial-seal clearance arrangement is considered, the agreement between CFD and experiments worsens; the variation of sealing effectiveness with coolant flow rate calculated by means of the simulations display a distinct kink. It was found that the “kink phenomenon” can be ascribed to an over-estimation of the egress spoiling effects due to turbulence modelling limitations. Despite some weaknesses in the numerical predictions, the paper shows that CFD can be used to characterize the sealing performance of axial- and radial-clearance turbine rim seals.
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Innocenti, Luca, Stefania Ricupero, Rajeev Kumar Pandit, and Nuo Sheng. "Experimental Analysis of Abradable Labyrinth Seal Leakage With Simulated Groove: Part 2." In ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/gt2013-95646.
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In the secondary flow path of centrifugal compressors, abradable seals are in high demand when higher efficiency is the main requirement. This is because abradable seals can maintain very tight clearances between static and rotating components compared to other sealing technology. However, due to the rubbing of the teeth into the abradable material, some grooves can form. The flow physics and mass leakage of abradable seals are strongly dependent on the presence of these grooves and their shape. For cases where no grooves are present, seal leakage is mainly a function of inlet pressure, pressure ratio across the seal and tooth radial clearance. Once grooves are formed, the flow physics and seal leakage also are a function of groove dimensions, tooth clearance and tooth axial position inside the groove. The scope of the present paper is to describe the experimental campaign that has been performed to validate the numerical analysis of part 1 of the paper [1]. The experimental test matrix investigates the groove and teeth positioning effects on seal leakages. To achieve higher accuracy, the key geometric parameters, such as radial and axial gaps, were controlled in the test sample during the tests. For cases where grooves are present the experimental measurements reveal that flow field strongly depends on groove dimensions, tooth radial clearance and tooth axial position. The authors, finally, found generally a good agreement between numerical predictions and measured data, both in terms of leakage and pressure drops across the teeth.
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Bohn, Dieter E., Achim Decker, Nils Ohlendorf, and Ralf Jakoby. "Influence of an Axial and Radial Rim Seal Geometry on Hot Gas Ingestion Into the Upstream Cavity of a 1.5-Stage Turbine." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90453.
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In gas turbines hot gas ingestion into the cavities between rotor and stator disks has to be avoided almost completely in order to ensure that the guaranteed lifetime of the turbine rotor disk will be reached. The influence of an axial and radial rim seal configuration geometry on the phenomenon of hot gas ingestion into the rim seal section and inside the front cavity of a 1.5-stage axial turbine is experimentally investigated. The results obtained for the reference axial configuration are compared to those for the radial configuration in the upstream cavity of the turbine. The hot gas ingestion phenomenon is examined for different flow parameters such as non-dimensional seal flow rate, Reynolds number in the main annulus and rotational speed. The sealing efficiency is determined by measurements of the carbon dioxide gas concentration in the cavity. Static pressure distributions are measured using pressure taps at the stator disk and rim seal lip. It will be shown for the axial rim seal geometry that the guide vanes mainly influence the flow field in the rim seal gap and inside the cavity whereas for the radial rim seal geometry such an influence is limited almost exclusively to the rim seal gap. For the radial rim seal a higher sealing efficiency was detected, mainly due to the different type of the rim seal.
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Lei, Xie, Wang RuoNan, Liu Guang, Lian ZengYan, and Du Qiang. "Numerical Investigation on Unsteady Characteristics in Different Rim Seal Geometries: Part A." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14832.
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Abstract Secondary sealing flow is of great importance in the turbine disk cooling and sealing system. The amount of cooling air extracted from the compressor is crucial to engine efficiency. To determine a minimum amount of cooling air, the flow characteristic of the rim seal should be investigated. Numerical simulation is carried out to investigate the flow field near the rim seal region. Both RANS and URANS numerical simulation methods are used in the commercial CFD code ANSYS CFX to analyze axial and radial rim seals. In the simulation, a 1/33 sector is selected as computing region to simulate the flow field and the SST turbulent model is used. The steady and unsteady simulation results of pressure distribution and seal efficiency are analyzed and compared. The computed results show that due to the different geometry configuration, the pressure distribution also shows inconsistency. Unsteady phenomena are observed in both axial and radial type of rim seals. Radial sealing lip can suppress the inherent unsteadiness and interaction between main flow and sealing flow, thus showing higher sealing efficiency. Comparing to steady results using the RANS method; unsteady simulation, using the URANS method, can capture the pressure difference and seal efficiency fluctuation at the disk rim more efficiently. Also, the interaction between the rotor and stator is considered in unsteady simulation, so the unsteady simulation is recommended. The results obtained in the current paper are useful to the investigation and design of turbine rim seals.
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Bayley, F. J., and C. A. Long. "A Combined Experimental and Theoretical Study of Flow and Pressure Distributions in a Brush Seal." In ASME 1992 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/92-gt-355.
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A relatively simple theory is presented which can be used to model the flow and pressure distributions in a brush seal matrix. The model assumes laminar, compressible, isothermal flow and requires knowledge of an empirical constant: the seal porosity value. Measurements of the mass flowrate together with radial and axial distributions of pressure were taken on a non-rotating experimental rig. These were obtained using a 122 mm bore brush seal with 0.25 mm radial interference. The experimental data are used to estimate the seal porosity. Measurements of the pressure distributions along the backing ring and under the bristle tips are discussed. Predicted mass flows are compared with those actually measured and there is reasonable agreement considering the limitations of the model.