Preliminary Investigations for a Pressure Balanced Back Plate at Low Inclined Brush Seals

Schwarz, H.; Friedrichs, Jens

doi:10.1115/gt2015-42580

Cited by 3 publications

(3 citation statements)

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“…In order to allow for a wide operating range, a novel seal design with pressure-actuated backplate based on the idea of Schwarz and Friedrichs (2015) was designed, targeting on the utilization of the positive operating properties of both the low and high inclined seals. The further development of Schwarz's concept into a testable configuration is presented.…”

Section: The Novel Seal Designmentioning

confidence: 99%

Investigation of a Novel Pressure-Actuated Brush Seal Under Hot Steam Conditions

Reggentin

Friedrichs

Flegler

et al. 2020

J. Glob. Power Propuls. Soc.

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Due to the increasing demand towards flexible operation of conventional power plants also the seals of their turbines have to adapt to varying loads. Based on the basic design of a clamped brush seal, a novel seal with a pressure-actuated backplate is introduced which is capable of combining the advantages of low and high inclined brush seals while avoiding their undesired properties for flexible operation. During preliminary investigations on a test rig operated with compressed air and without rotation, the functionality of the improved design was demonstrated. It is shown that the leakage mass flow was lowered by up to 40% while undesired bristle oscillations were reduced by up to 90% at low pressure differences compared to conventional seal designs. After the adaption of the design for subsequent investigations under realistic conditions comparable to those in a steam turbine, further tests were conducted at TU Braunschweig's hot steam test rig. Within these investigations the novel design showed improved properties regarding a high leakage performance and an advanced capability to avoid deterioration due to shaft excursions compared to brush seals with fixed backplate design.

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Section: The Novel Seal Designmentioning

confidence: 99%

Investigation of a Novel Pressure-Actuated Brush Seal Under Hot Steam Conditions

Reggentin

Friedrichs

Flegler

et al. 2020

J. Glob. Power Propuls. Soc.

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“…The stiffness itself is calculated for a displacement increment of 0.1 mm based on the maximum displacement and the corresponding force difference (see Figure 3). Reproduced with permission from [7], Copyright@ ASME, 2015.…”

Section: Cold Air Test Facility (Ifas)mentioning

confidence: 99%

“…Figure 2. Main test arrangements ((A): blow-down; (B): axial behaviour of the bristle pack; (C): stiffness).Reproduced with permission from[7], Copyright@ ASME, 2015.…”

mentioning

confidence: 99%

Effects of the Back Plate Inner Diameter on the Frictional Heat Input and General Performance of Brush Seals

et al. 2018

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Reducing losses in the secondary air system of gas and steam turbines can significantly increase the efficiency of such machines. Meanwhile, brush seals are a widely used alternative to labyrinth seals. Their most valuable advantage over other sealing concepts is the very small gap between the sealing package and the rotor and thus reduced leakage mass flow. This small gap can be achieved due to the great radial flexibility 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. This paper is a contribution to further understand the influence of the geometrical parameters of the brush seal on the heat input and the leakage during the rubbing of the seal on the rotor. In this paper, a total of three seals with varied back plate inner diameter are examined in more detail. The experimental tests were carried out on the brush seal test rig of the Institute of Thermal Turbomachinery (ITS) under machine-relevant conditions. These are represented by pressure differences of 1 to 7 bar, surface speeds of 30 to 180 m/s and radial interferences of 0.1 to 0.4 mm. For a better interpretation, the results were compared with those obtained at the static test rig of the Institute of Jet Propulsion and Turbomachinery (IFAS) at the Technical University of Braunschweig. The stiffness, the blow-down and the axial behaviour of the seals as a function of the differential pressure can be examined at this test rig. It could be shown that the back plate inner diameter has a decisive influence on the overall operating behaviour of a brush seal.

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Various cooling systems for advanced gas turbine jets: efficiency study

Malinovskiy¹,

Nesterenko

Starodumov³

et al. 2022

EJSI

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The paper focuses on foreign and Russian aviation bypass turbojets with an afterburner, studies the design of their turbine cooling systems, and introduces the research findings. For computational research and comparative analysis, we used Russian and foreign samples of advanced bypass turbojets with an afterburner with the most optimal technical characteristics, made calculations of the gas-dynamic parameters of their cooling systems in four critical jet operating modes. In this paper, we introduce the results of hydraulic calculations of various schemes for supplying cooling air to the nozzle and working blades of a high-pressure turbine. Relying on the results of the calculation, we comparatively analyzed the foreign and Russian cooling systems design, in terms of power indicators and efficiency of a gas turbine jet. To do this, we used the following parameters: cooling air bleeding value at maximum jet speed and cruising mode, value of cooling air leakage through the axial gaps into the flow path, the change in the cooling air bleeding value as a percentage of the flow rate through the high-pressure compressor when switching from maximum to cruising mode, i.e. adaptability of the cooling system, the temperature of the cooling air at the point of supply to the cooling cavities of the blade of the nozzle apparatus or the working blade.

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Preliminary Investigations for a Pressure Balanced Back Plate at Low Inclined Brush Seals

Cited by 3 publications

References 0 publications

Investigation of a Novel Pressure-Actuated Brush Seal Under Hot Steam Conditions

Investigation of a Novel Pressure-Actuated Brush Seal Under Hot Steam Conditions

Effects of the Back Plate Inner Diameter on the Frictional Heat Input and General Performance of Brush Seals

Various cooling systems for advanced gas turbine jets: efficiency study

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