Indeed, many gas turbine engine seals leak by design. Brush seals are a proven technology in the aerospace and power generation industries, delivering significant efficiency improvements over traditional labyrinth seals. Compared with conventional labyrinth seals, mtu brush seals reduce leakage rates in engines, gas turbines, steam turbines and compressors by up to 80%. While odessa babbitt bearing is most often associated with babbitt bearings, our second largest product line is labyrinth seals. In addition, stiffness recovery by crack healing was lower in specimens. The tip thickness of labyrinth glands is made as thin as practicable so that if an accidental rub occurs between the shaft and the gland, the fins will rub away with little heating of the shaft. Dec 03, 2015 overlooked gland seal can be big trouble december 3, 2015 in steam turbine tips by psgweb the steam turbine gland steam seal system is designed to keep steam from leaking out of the turbine and to prevent air from leaking into the turbine. Because liquidfilled labyrinth seals still generate heat due to the viscosity of the seal oil, and because seal oil can contaminate the process fluids, modern highperformance gas turbines use dry gas seals which use springloaded rings with an inert gas in between the faces of the rings to provide the seal. Conditions subject to which replacement of conventional seals by honeycomb ones can be justified are pointed out. Primary and secondary seal modules are oriented in the same direction, with or without an integrated intermediate labyrinth seal. Gas turbine engine bearings and seals flight mechanic. John crane type 28st dry gas seals ensure reliability and uptime in missioncritical applications.
Request pdf brush seals and labyrinth seals in gas turbine applications the overall efficiency of gas turbines is strongly affected by the performance of the. Each time the steam passes through one of the small gaps, its pressure is reduced somewhat. Seals are basic mechanical devices used in machinery to avoid undesired flow losses of working fluids. Our database of drawings is extensive with more than 10,000 different labyrinth seals. Cross is a leading innovator and manufacturer of brush seals for new equipment and for performance enhancing projects on existing equipment. Labyrinth packing an overview sciencedirect topics.
Any oil that makes it past the first part of the seal is thrown outwards due to the centrifugal force, forms vortices and therefore cannot pass the second part. All dry gas seals need additional protection from the process and the bearing lubrication sides of the seal history. The method of separation gas control depends on the type of seal selected. Evaluation of rotordynamic stability of a steam turbine due. Another type of oil seal used on some of the later engines is the carbon seal. Us9683452b2 labyrinth seal for gas turbine engine turbine. In this video we will describe how compressor gas seal system work. Brush seals and labyrinth seals in gas turbine applications. Assume 4% of the compressor efficiency loss is attributable to internal labyrinth seals. If a crack does occur due to stress or fatigue, the multiple plies will contain. A labyrinth seal for a gas turbine engine of the type having a high pressure compressor and high pressure turbine, an outer shaft interconnecting the high pressure compressor and turbine, a low pressure compressor and turbine, and an inner shaft interconnecting the low pressure compressor and turbine in which the shafts are concentric and are separated by the seal.
Leakage reduction by mtu brush seals threefin straight labyrinth seal threefin stepped labyrinth seal mtu brush seal 5 patented design advantages of the mtu brush seal. The seals shaft is protected from the fluid in the top labyrinth chamber by the shaft guide tube. Oct 15, 2016 labyrinth packing creates a series of small gaps that the steam must go through in order to escape. May 18, 1993 accordingly, there is a need for a labyrinth seal designed for use between two corotating or counterrotating components in a gas turbine engine which does not transmit stress cracks to the component on which it is mounted and which effects a highly efficient seal. When this arrangement has been made, it is then customary to fit at least two special carbon gland rings between the balance.
Sealing efficiency an overview sciencedirect topics. The seal steam system enables the turbine to be sealed where the shaft exits the casingin effect keeping air out and steam in. The challenges associated with developing brush seals for steam turbine applications include very high operating pressures and rotordynamic effects. Labyrinths are the most frequently used gas seals in engines. Advanced labyrinth seals for steam turbine generators. Significant surface cracking indi cates a significant. When using labyrinth seals, purging gas at a pressure higher than the.
In these applications, it is the long and difficult path and the formation of controlled fluid vortices plus some limited contactsealing action that creates the seal. Rotordynamics of turbine labyrinth seals with rotor axial. September though when a cracked knife edge was discovered. Rotors in highperformance steam turbines experience a significant axial shifting during starting and stopping processes due to thermal expansion, for example. Inboard of the dry gas seal is an inner labyrinth seal, which separates the process gas from the gas seal. As turbine exhaust is connected to a condenser which is operated below atm pressure so there are chances of air ingres or va. A labyrinth seal for a gas turbine engine of the type having a high. Honeycombbrazing essentials for successful use as turbine seals. Selection of labyrinth seals in steam turbines springerlink. It is a proven rotating groove technology that reduces steam leakage, compared to traditional sealing devices. Labyrinth seals for gas turbine engine general electric company. The primary seal process gas side handles the full pressure drop, and the secondary seal atmosphere side serves as a.
This is evident by the latest advances weve made in seal face technology and seal design. An inexpensive and effective labyrinth seal can be made using pressed steel sealing washers. Type 28st dry gas seals john crane mechanical seals. The labyrinth seal of a large scales steam turbine is taken as an object of analysis and a 3d model with eccentric rotor is solved to obtain the rotordynamic force components. Sets of labyrinth packing are used along the turbine rotor where the rotor exits the turbine casing to maintain this pressure differential between inside and outside. A comparison between the conventional and honeycomb seals is given.
Particularly annular seals are one of the most widely used in. A turbine for a gas turbine engine comprising at least one turbine stator and one turbine rotor, said turbine stator comprising at least one inner annular platform, said inner platform comprising a radial wall delimiting at least one cavity between the turbine stator and the turbine rotor, wherein the turbine rotor comprises at least one elongate element positioned substantially axially and. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Explainmedia created this video in a joint venture with esd simulation training. For carbon ring seals, pressure control could limit. The rotordynamic force is derived by integrating the pressure on the rotor surface. Outboard of the dry gas seal is a barrier seal, which separates the gas seal from the compressor shaft bearings fig. Labyrinth seals are also found on pistons, which use them to store oil and seal against high pressure during compression and power strokes, as well as on other nonrotating shafts. The seals annular cavities provide a tortuous path that minimizes gas leakage.
The depth of our experience in gas turbine and other industrial applications for mechanical seals is unmatched. The labyrinth seal is usually pressurized, but the helical seal depends solely on reverse threading to stop oil leakage. An example of such a seal is sometimes found within an axles bearing to help prevent the leakage of the oil lubricating the bearing. The typical utility steam turbine brush seal configuration is shown in figure 2. Labyrinth seals for gas turbine engine general electric. Manufacturer of steam turbine labyrinth seal turbine labyrinth brush, turbine labyrinth seal offered by swarup industry, new delhi, delhi. Overlooked gland seal can be big trouble power services group. Steam turbine labyrinth seal turbine labyrinth brush. Apr 20, 2015 we are excited to announce the release of the first centrifugal compressor training video developed in over 20 years. Performance and reliability improvements for heavyduty gas turbines. Oct 31, 2015 labyrinth seals, noncontact type mechanical seals, consisting of a series of annular orifices or cavities, are critical components in a centrifugal gas compressor. Thermoplastic labyrinth seals in centrifugal compressors 15. Figure 6 shows the original labyrinth seal design between the compressor. Labyrinth seals article about labyrinth seals by the free.
The main function of labyrinth seals are to help prevent leakeage. Design integration integration of abradables seal coatings into existing steam turbine labyrinth seals is relatively easily achieved by simply using the abradable coating system bond and top coat thickness to reduce the seal clearance. Leadingedge, noncontacting face technologies the gas turbine industry demands seals that operate at. This axial shifting could significantly alter the flow pattern and the flowinduced rotordynamic forces in labyrinth seals, which in turn, can considerably affect the rotor seal system performance. Aug 17, 2010 honeycombbrazing essentials for successful use as turbine seals august 17, 2010 by dan kay a honeycomb structure serves as an excellent gas flow seal and a sacrificial wearsurface to rotating turbine blades in hightemperature turbines. Sep 11, 2018 in this video we will describe how compressor gas seal system work. For large machines a direct drive with a steam turbine is often used but an. A labyrinth seal is a type of mechanical seal that provides a tortuous path to help prevent leakage. The use of variablepitch multicomb seals as the most promising. Likewise, the web of the ushaped inner ring, on its surface facing the rotor, has one half of a labyrinth seal, which together with the second half arranged on the rotor forms the labyrinth seal. Brush seals and labyrinth seals in gas turbine applications request.
It is a proven rotating groove technology that reduces steam leakage, compared to. These two types of seals are very similar, differing only in thread size and the fact that the labyrinth seal is pressurized. Labyrinth seals labyrinth seal manufacturer odessa babbitt. These multiple labyrinth seal systems take up considerable space and are generally too costly and difficult to accommodate in small engines. Wyssmann sulzerescher wyss ltd zurich, switzerland the prediction of rotordynamic coefficients for gas seals is achieved with the aid of a twovolume bulk flow model based on turbulent rotationally symmetric 3d flow calculations including swirl.
I believe i understand how a labyrinth seal in a turbine engine works when a the engine is running. Us20110150640a1 labyrinth seal in a stationary gas turbine. In aircraft and electric power generation gas turbine engines alike, it is. Apr 17, 2014 a turbine stator for a turbine as claimed in claim 1, said turbine stator comprising at least one element made of abradable material which is designed to engage with at least one spur of a turbine rotor of said turbine so as to form a labyrinth seal. Field applications of dry gas seal designs were completed in 1952. Dec 17, 2014 the efficiency, vibration stability, operational durability, and cost of the main types of peripheral seals used in steam turbines are considered. What is the difference between carbon and labyrinth packing. A minimumleakage seal that offers resistance to fluid flow while providing radial or axial clearance. For labyrinth and abradable labyrinth seals, the best practice is to use differential pressure control seal supply pressure secondary vent pressure to each seal. An experimental study of the high speed interaction. Extensive investigations on radial crack formation in labyrinth. The tandem seal configuration is the most common in the oil and gas industry. If a crack is found through visual inspection, the part is. Evaluation formula is formed from the results of numerical calculation, which is used.
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