Academic literature on the topic 'Labyrinth packing'
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Journal articles on the topic "Labyrinth packing"
1
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.
Full textAbstract:
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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Mammar, Lahouari, Yahiaoui Tayeb, Omar Ladjedel, and Ondřej Šikula. "Fluid Thermal Effect on Non-contacting Labyrinth Seal of 20 MW Steam Turbine." Periodica Polytechnica Mechanical Engineering 64, no. 1 (December 17, 2019): 31–42. http://dx.doi.org/10.3311/ppme.14176.
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This paper is divided into two parts; the first describes a CFD analysis of a gland packing labyrinth seals in 20 MW steam turbine in LNG plant using ANSYS CFX code as an isothermal simulation in fluid domain. The results of two turbulence models k-ε and k-ω SST are compared and validated against experimental data. It is shown that the labyrinth seal leakage is proportional to the clearance cube so any variation in clearance can have a significant impact on the steam leakage. This clearance between the shaft and the labyrinth seal vary as a function of operating temperature due to the different rates of thermal expansion of the materials for these two components. Likewise the fluid temperature has a direct effect on fluid dynamic behavior. For that; the second part of the paper investigates the effect of fluid thermal conditions of the labyrinth seal via the heat transfer and Nusselt number variation in the stator and the rotor, for different cases of inlet temperature (400 °C, 200 °C, 100 °C, 50 °C) and pressure ratio (2.5, 4.5, 6.5) for an ideal gas. Also it is important to know the temperature distribution across tooth and cavities of the labyrinth seal, and finally the Influence of Inlet total temperature on fluid pressure drop in the labyrinth seal will be treated for improving and readjusting the steam turbine sealing system.
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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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Ridwan, Mohamad, Rosna Yuherlina, and Dimas Andhika Putra. "Analisa dan Penanganan Terjadinya Penurunan Kevakuman pada Kondensor Utama Terhadap Kinerja Turbin Uap Di Kapal LNG." Prosiding Seminar Pelayaran dan Teknologi Terapan 2, no. 1 (October 27, 2020): 130–39. http://dx.doi.org/10.36101/pcsa.v2i1.134.
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Penggunaan turbin uap sangat diperlukan dalam penggerak utama kapal LNG. Tujuan penelitian ini adalah untuk mengetahui faktor-faktor apa yang mempengaruhi terjadinya penurunan kevakuman pada kondensor utama, dampak yang terjadi dengan adanya penurunan kevakuman pada kondensor utama dan upaya yang dapat dilakukan untuk mengatasi turunnya kevakuman di kondensor utama tersebut. Penelitian ini menggunakan metode kualitatif deskriptif yang bersifat eksplorasi untuk menggambarkan atas suatu fenomena. Fenomena yang diambil adalah tentang penurunan kevakuman pada main condenser yang berpengaruh besar terhadap kinerja dari main turbin. Kebocoran udara di dalam sistem, vacuum pump yang tidak normal, pengaruh tekanan dan temperature air pendingin kondensor, serta kesalahan pengoperasian adalah beberapa hal yang mempengaruhi penurunan kevakmuman tersebut. Penurunan kevakuman tersebut dapat menyebabkan sistem uap utama menjadi terganggu dan mengalami fail (auto slowdown) pada main turbin. Dan hal tersebut dapat diatasi dengan melakukan perawatan pada sistem dan meminimalisir kesalahan pengoperasian. Dari hasil penelitian disimpulkan bahwa penurunan kevakuman disebabkan oleh beberapa faktor diantaranya kebocoran udara ke dalam sistem melalui sambungan flans dan packing labyrinth, kinerja vacuum pump yang tidak optimal, turunnya tekanan air pendingin main condenser, naiknya suhu air pendingin yang dipengaruhi oleh faktor alam, dan kesalahan pengoperasian dalam menjalankan turbo generator
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Sherstyuk, A. N., and V. S. Orbis-Diyas. "Effect of leakages through labyrinth packings of cover plate on the stage characteristics of a centrifugal compressor." Chemical and Petroleum Engineering 25, no. 4 (April 1989): 173–75. http://dx.doi.org/10.1007/bf01218800.
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Lalvani, Haresh. "Non-periodic Space Structures." International Journal of Space Structures 2, no. 2 (June 1987): 93–108. http://dx.doi.org/10.1177/026635118700200204.
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An interesting class of two- and three-dimensional space structures can be derived from projections of higher-dimensional structures. Regular polygons and regular-faced polyhedra provide the geometry of families of n-stars from which two- and three-dimensional projections of n-dimensional grids can be derived. These projections are rhombic space grids composed of all-space filling rhombi and rhombohedra with edges parallel to n directions. An infinite class of single-, double- and multi-layered grids can be derived from n-sided polygons and prisms, and a finite class of multi-directional grids from the polyhedral symmetry groups. The grids can be periodic, centrally symmetric or non-periodic, and act as skeletons to generate corresponding classes of space-filling, packings and labyrinths.
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Tang, Xufeng, Xue Sun, Fangwei Zhang, Zhidan Liu, and Shuhong Wang. "Method for Zoning Operation of Roundabout Warehouse for Packaging Dangerous Goods under Safety Red Line." Maritime Technology and Research 2, no. 4 (May 2, 2020): Manuscript. http://dx.doi.org/10.33175/mtr.2020.237444.
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In order to comprehensively consider the safety, efficiency and other factors in the in-and-out operation of dangerous goods, this studytakes the setting of forklift rounding rules as the research background and uses optimization theory and the newly proposed cost formula to study the partitioning question of the warehouse. The practical innovation of this study is to propose the concept of the safety red line as well as obtain the safety formula under this circumstances. The theoretical innovation of this paper is to combine the labyrinth path finding algorithm and the utility theory together to solve the problem of in-and-out operations of the dangerous goods. The application field of the results in this essay includes dangerous goods warehouse management and may extend to all kinds of management in warehouse. Finally, this study takes the actual data of Shanghai Lingang Dangerous Goods Warehouse as parameters and uses the dual-container-truck out operation and single-container-truck in operation as examples. Simulation technology is also used to verify the newly proposed model as well as its validity and feasibility
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"Packing acts like a labyrinth seal." Sealing Technology 1996, no. 28 (April 1996): 3–4. http://dx.doi.org/10.1016/s1350-4789(96)80036-5.
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Childs, Dara W., James E. Mclean, Min Zhang, and Stephen P. Arthur. "Rotordynamic Performance of a Negative-Swirl Brake for a Tooth-on-Stator Labyrinth Seal." Journal of Engineering for Gas Turbines and Power 138, no. 6 (November 24, 2015). http://dx.doi.org/10.1115/1.4031877.
Full textAbstract:
In the late 1970s, Benckert and Wachter (Technical University Stuttgart) tested labyrinth seals using air as the test media and measured direct and cross-coupled stiffness coefficients. They reported the following results: (1) fluid preswirl in the direction of shaft rotation creates destabilizing cross-coupled stiffness coefficients and (2) effective swirl brakes at the inlet to the seal can markedly reduce the cross-coupled stiffness coefficients, in many cases reducing them to zero. In recent years, “negative-swirl” swirl brakes have been employed, which attempt to reverse the circumferential direction of inlet flow, changing the sign of the cross-coupled stiffness coefficients and creating stabilizing stiffness forces. This study presents test results for a 16-tooth labyrinth seal with positive inlet preswirl (in the direction of shaft rotation) for the following inlet conditions: (1) no swirl brakes, (2) straight, conventional swirl brakes, and (3) negative-swirl swirl brakes. The negative-swirl swirl-brake designs were developed based on computational fluid dynamics (CFD) predictions. Tests were conducted at 10.2, 15.35, and 20.2 krpm with 70 bar of inlet pressure for pressure ratios of 0.3, 0.4, and 0.5. Test results include leakage and rotordynamic coefficients. In terms of leakage, the negative-swirl brake configuration leaked the least, followed by the conventional brake, followed by the no-brake design. Normalized to the negative-swirl brake configuration, the conventional-brake and no-brake configurations mass flow rate was greater, respectively, by factors of 1.04 and 1.09. The direct-stiffness coefficients are negative but small, consistent with past experience. The conventional swirl brake drops the destabilizing cross-coupled stiffness coefficients k by a factor of about 0.8 as compared to the no-brake results. The negative-swirl brake produces a change in sign of k with an appreciable magnitude; hence, the stability of forward precessing modes would be enhanced. In descending order, the direct-damping coefficients C are: no-swirl, negative-swirl, and conventional-swirl. Normalized in terms of the no-swirl case, C for the negative and conventional brake designs is, respectively, 0.7 and 0.6 smaller. The effective damping Ceff combines the effect of k and C. Ceff is large and positive for the negative-swirl configuration and near zero for the no-brake and conventional-brake designs. The present results for a negative-brake design are very encouraging for both eye-packing seals (where conventional swirl brakes have been previously employed) and division-wall and balance-piston seals, where negative shunt injection has been employed.
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Hildebrandt, Manuel, Corina Schwitzke, and Hans-Jörg Bauer. "Experimental Investigation on the Influence of Geometrical Parameters on the Frictional Heat Input and Leakage Performance of Brush Seals." Journal of Engineering for Gas Turbines and Power 141, no. 4 (February 27, 2019). http://dx.doi.org/10.1115/1.4038767.
Full textAbstract:
Because of the superior sealing characteristics compared to labyrinth seals, brush seals found an increased spread in turbomachinery in recent years. Their outstanding sealing performance results mainly from their flexibility. Thus, a very small gap between the rotor and bristle package can be obtained without running the risk of severe detrimental deterioration in case of rubbing. Rubbing between rotor and seal during operation might occur as a result of e.g., an unequal thermal expansion of the rotor and stator or a rotor elongation due to centrifugal forces or maneuver forces. Thanks to the flexible structure of the brush seal the contact forces during a rubbing event are reduced; however, the frictional heat input can still be considerable. Particularly, in aircraft engines with their thin and lightweight rotor structures, the permissible material stresses can easily be exceeded by an increased heat input and thus harm the engine's integrity. The geometry of the seal has a decisive influence on the resulting contact forces and consequently the heat input. The complex interactions between the geometric parameters of the seal and the heat input and leakage characteristics are not yet fully understood. This paper presents the investigation of the influence of the geometric parameters of a brush seal on the heat input into the rotor and the leakage behavior. Two seals with different packing densities were tested under relevant engine conditions with pressure differences ranging from 1 to 7 bar, relative surface speeds ranging from 30 to 180 m/s, and radial overlaps ranging from 0.1 to 0.4 mm. The transient temperature rise during the rub event was recorded with 24 thermocouples in close proximity to the rub contact embedded in the rotor structure. By comparing the temperature curves with the results of a thermal finite element (FE) analysis of the rotor the heat input into the rotor was calculated iteratively. It could be shown that the packing density has a decisive influence on the overall operating behavior of a brush seal. Furthermore, results for the heat flux distribution between seal and rotor are shown.
Dissertations / Theses on the topic "Labyrinth packing"
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Бондаренко, Герман Андрійович, Герман Андреевич Бондаренко, Herman Andriiovych Bondarenko, Вадим Миколайович Бага, Вадим Николаевич Бага, and Vadym Mykolaiovych Baha. "Влияние физических свойств газов на характеристики лабиринтного уплотнения." Thesis, Сумский государственный университет, 2015. http://essuir.sumdu.edu.ua/handle/123456789/39428.
Full textConference papers on the topic "Labyrinth packing"
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Roy, Binayak, Hrishikesh V. Deo, and Xiaoqing Zheng. "Progressive Clearance Labyrinth Seal for Turbo-Machinery Applications." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64870.
Full textAbstract:
Turbomachinery sealing is a challenging problem due to the varying clearances caused by thermal transients, vibrations, bearing lift-off etc. Leakage reduction has significant benefits in improving engine efficiency and reducing emissions. Conventional labyrinth seals have to be assembled with large clearances to avoid rubbing during large rotor transients. This results in large leakage and lower efficiency. In this paper, we propose a novel Progressive Clearance Labyrinth Seal that is capable of providing passive fluidic feedback forces that balance at a small tip-clearance. A modified packing ring is supported on flexures and employs progressively tighter teeth from the upstream to the downstream direction. When the tip-clearance reduces below the equilibrium clearance, fluidic feedback forces cause the packing ring to open. Conversely, when the tip-clearance increases above the equilibrium clearance, the fluidic feedback forces cause the packing ring to close. Due to this self-correcting behavior, the seal provides high differential pressure capability, low leakage and non-contact operation even in the presence of large rotor transients. Theoretical models for the feedback phenomenon have been developed and validated by experimental results.
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Vakili, Ahmad D., Abraham J. Meganathan, Sricharan Ayyalasomayajula, Stephen Hesler, and Lewis Shuster. "Advanced Labyrinth Seals for Steam Turbine Generators." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-91263.
Full textAbstract:
A new class of knives (C-Shaped) for reduced labyrinth seal discharge has been designed and assessed through two dimensional numerical modeling of the seal’s internal flow passages. Modeling procedures used for the analysis have been previously validated by comparison with static labyrinth seal experiments. The objectives of the new seal are to: 1) reduce flow leakage through the seal and 2) introduce structural flexibility in the knives so that design clearances could be maintained even after rub events during startup. The baseline chosen for comparative evaluation is an N2 packing used in GE steam turbines. The new seals have compliant C-shaped knives instead of the straight knives, found in an N2 packing. The best performing configuration has one tall ‘C’ shaped long knife and three ‘C’ shaped short knives in each stage. It was found that the best configuration at clearances similar to the baseline seal reduces flow leakage by 42%. Two dimensional numerical structural analyses showed that the new seal knife is more flexible than a straight knife. This is also intuitive by virtue of its geometric profile. A non-dimensional geometric parameter correlates with the degree of flexibility in the knife. These results indicate a potential for design of labyrinth seals that maintain lower design clearances throughout their life time by carefully selecting the knives’ geometric parameters and incorporating high performance composite materials. Then, the new design would result in significantly lower steam leakage.
3
Childs, Dara W., James E. Mclean, Min Zhang, and Stephen P. Arthur. "Rotordynamic Performance of a Negative-Swirl Brake for a Tooth-on-Stator Labyrinth Seal." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-25577.
Full textAbstract:
In the late 1970’s, Benckert and Wachter (Technical University Stuttgart) tested labyrinth seals using air as the test media and measured direct and cross-coupled stiffness coefficients. They reported the following results: (1) Fluid pre-swirl in the direction of shaft rotation creates destabilizing cross-coupled stiffness coefficients, and (2) Effective swirl brakes at the inlet to the seal can markedly reduce the cross-coupled stiffness coefficients, in many cases reducing them to zero. In recent years, “negative-swirl” swirl brakes have been employed that attempt to reverse the circumferential direction of inlet flow, changing the sign of the cross-coupled stiffness coefficients and creating stabilizing stiffness forces. This study presents test results for a 16-tooth labyrinth seal with positive inlet preswirl (in the direction of shaft rotation) for the following inlet conditions: (1) No swirl brakes, (2) Straight, conventional swirl brakes, and (3) Negative-swirl swirl brakes. The negative-swirl swirl-brake designs were developed based on CFD predictions. Tests were conducted at 10.2, 15.35, and 20.2 krpm with 70 bars of inlet pressure for pressure ratios of 0.3, 0.4, 0.5. Test results include leakage and rotordynamic coefficients. In terms of leakage, the negative-swirl brake configuration leaked the least, followed by the conventional brake, followed by the no-brake design. Normalized to the negative-swirl brake configuration, the conventional-brake and no-brake configurations mass flow rate were greater, respectively, by factors of 1.04 and 1.09. The direct stiffness coefficients are negative but small, consistent with past experience. The conventional swirl brake drops the destabilizing cross-coupled stiffness coefficients k by a factor of about 0.8 as compared to the no-brake results. The negative-swirl brake produces a change in sign of k with an appreciable magnitude; hence, the stability of forwardly-precessing modes would be enhanced. In descending order, the direct damping coefficients C are: no-swirl, negative-swirl, conventional-swirl. Normalized in terms of the no-swirl case, C for the negative and conventional brake designs are, respectively, 0.7 and 0.6 smaller. The effective damping Ceff combines the effect of k and C. Ceff is large and positive for the negative-swirl configuration and near zero for the no-brake and conventional-brake designs. The present results for a negative-brake design are very encouraging for both eye-packing seals (where conventional swirl brakes have been previously employed) and division-wall and balance-piston seals where negative shunt injection has been employed.
4
Hildebrandt, Manuel, Corina Schwitzke, and Hans-Jörg Bauer. "Experimental Investigation on the Influence of Geometrical Parameters on the Frictional Heat Input and Leakage Performance of Brush Seals." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63423.
Full textAbstract:
Because of the superior sealing characteristics compared to labyrinth seals, brush seals found an increased spread in turbomachinery in recent years. Their outstanding sealing performance results mainly from their flexibility. Thus, a very small gap between the rotor and bristle package can be obtained without running the risk of severe detrimental deterioration in case of rubbing. Rubbing between rotor and seal during operation might occur as a result of e.g. an unequal thermal expansion of the rotor and stator or a rotor elongation due to centrifugal forces or manoeuvre forces. Thanks to the flexible structure of the brush seal the contact forces during a rubbing event are reduced, however the frictional heat input can still be considerable. Particularly in aircraft engines with their thin and lightweight rotor structures the permissible material stresses can easily be exceeded by an increased heat input and thus harm the engine’s integrity. The geometry of the seal has a decisive influence on the resulting contact forces and consequently the heat input. The complex interactions between the geometric parameters of the seal and the heat input and leakage characteristics are not yet fully understood. This paper presents the investigation of the influence of the geometric parameters of a brush seal on the heat input into the rotor and the leakage behaviour. Two seals with different packing densities were tested under relevant engine conditions with pressure differences ranging from 1 to 7 bar, relative surface speeds ranging from 30 to 180 m/s and radial overlaps ranging from 0.1 to 0.4 mm. The transient temperature rise during the rub event was recorded with 24 thermocouples in close proximity to the rub contact embedded in the rotor structure. By comparing the temperature curves with the results of a thermal finite element analysis of the rotor the heat input into the rotor was calculated iteratively. It could be shown that the packing density has a decisive influence on the overall operating behaviour of a brush seal. Furthermore, results are obtained for the heat flux distribution between seal and rotor are shown.
5
Atlason, Reynir S., Almar Gunnarsson, and Runar Unnthorsson. "Necessity is the Mother of Invention: The Dawn of Domestic Geothermal Turbine Repairs in Iceland." In ASME 2014 Power Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/power2014-32304.
Full textAbstract:
Even though the Icelandic public relies greatly on geothermal power, to date, intensive maintenance procedures on the geothermal turbines have been conducted by foreign contractors. Such repairs are very time consuming, risky, expensive and leak capital out of the country. This has been discussed greatly within the industry and plans have been made on how the power companies, along with domestic machine shops can address this problem. However, in spring 2013 a turbine failure was observed in a routine quadrennial check at the Nesjavellir geothermal power plant. Corrosion products where found on the last set of the labyrinth packing and the rotor had been worn down approximately 8 mm radius. The backup rotor was also in a non-operational state. The unexpected downtime in power production had to be minimized in order to fulfill contracts. Because of time constraints, foreign service companies were not considered to be feasible due to their waiting queues and the time required for shipping overseas. This scenario initiated collaboration between the power company and domestic machine shops to manufacture spare parts and conduct the overall repair on site. This was due to several reasons such as; currency exchange rate, machines and know-how at the machine shops had improved over the last decade and the fact that the power company was ready to pay for the development cost. This paper presents the problem, how it was solved collaboratively domestically in only a fraction of time that conventional procedures would have taken. The paper investigates the causes of the turbine failure and provides a description the current state of turbine repair facilities in Iceland.
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Ingistov, Steve. "Upgrades of Steam Turbine Generator Units in Watson Cogeneration Combined Cycle Plant." In ASME Turbo Expo 2002: Power for Land, Sea, and Air. ASMEDC, 2002. http://dx.doi.org/10.1115/gt2002-30251.
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This paper describes efforts that were implemented in modifying two Steam Turbine Generators (STG) that are presently operating in Watson Cogeneration Company (WCC) Plant. WCC Plant is comprised of four identical GE made Gas Turbine Generators (GTG) and four Heat Recovery Steam Generators (HRSG) designed and fabricated by Vogt. Portion of high pressure steam is expanded inside two Dresser-Rand-made Steam Turbine Generators (STG). The modifications presented in this paper include replacement of six original stages of expansion, introduction of shaft retractable labyrinths/packing and installation of the spill strips around shrouded blades. The modifications of high pressure steam path (except 1st stage blading) were completed in 1992 and modification of rotor steam sealing elements such as shaft labyrinths were completed in April and May 2001. The steam path modification uprated STG from original 34.50MW to present 40MW each. The upgrades of the rotor sealing elements resulted in 2.80% Heat Rate (HR) reduction.