Effects of Clearance on Leakage Flow Characteristics of Labyrinth Brush Seal

Yuan, Wancheng; Chen, Zhaobo; Jiao, Yu; Du, Xiaoxu; Zhang, Zhouqiang

doi:10.1007/978-3-319-06590-8_167

Cited by 3 publications

(3 citation statements)

References 14 publications

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“…For less detailed and more computationally efficient modeling of leakage flow and aerodynamic effects, porous medium representations of the bristle pack are often used within CFD models, Bayley and Long (1993), Wei et al (2015), and Gresham et al (2016) introduced a leakage based on a linear porous medium model for comparison with their experimental results. Chew et al (1995) proposed a nonlinear, anisotropic porous treatment and calibrated the viscous and inertial coefficients with experimental data.…”

Section: Introductionmentioning

confidence: 99%

Flow Conditioning to Control the Effects of Inlet Swirl on Brush Seal Performance in Gas Turbine Engines

et al. 2022

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When subject to highly swirling inlet flow, the bristles on the upstream face of a brush seal in gas turbine engines tend to slip circumferentially, which may lead to aeromechanical instability and seal failure. In this article, a new design of the front plate of brush seal, which mitigates this effect, is presented. Angled ribs on the upstream side of the front plate are used to reduce the swirl of the flow impacting on the bristle pack. The effects of the rib geometry, including angle of inclination and height-to-spacing ratio, are investigated using computational fluid dynamics, and a bulk porous medium model of the bristle pack, on a simple seal geometry. Results show that the ribs can effectively regulate the flow upstream of the bristle pack, reducing the swirl and channeling flow radially inward to the sealing section, resulting in decreased circumferential forces on the bristles. Ribs inclined at 20° to the radial direction and with height-to-spacing ratio of 0.4 were selected as the most effective of those investigated for the seal geometry under study. A model of an aeroengine preswirled cooling air chamber was created to give insight into the inlet swirl boundary conditions that a preswirl seal brush seal could be subjected to at a range of leakage flow rates and inlet swirl velocities. The new design and upstream roughness feature substantially reduced inlet swirl velocity incident on the bristle pack. The findings in this work could have a significant impact on brush seal design and, in particular, mitigate a significant operational risk of swirl-induced instability in high-pressure, high-speed shaft seal locations.

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Section: Introductionmentioning

confidence: 99%

Flow Conditioning to Control the Effects of Inlet Swirl on Brush Seal Performance in Gas Turbine Engines

et al. 2022

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“…In general, works featuring the use of high speed torque sensors to measure the brush seal forces are very limited in the open literature. And while parametric investigations (numerical or experimental), performed by Dogu et al Wei et al or Outirba et al [24][25][26] are slowly becoming an interest of the turbomachinery community regarding the leakage performance, they are yet to focus on the tribological performance.…”

Section: Introductionmentioning

confidence: 99%

Experimental characterization of friction and heat generation of carbon fibre brush seals for aero-engines

Outirba

Hendrick

2020

Tribology International

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Brush seals have been extensively studied for the last thirty years as an advanced sealing solution for gas turbine engines. The research is always aimed towards the reduction of the leakage flow, that has direct repercussions on the specific fuel consumption, the thrust-to-weight ratio, and the emission of pollutants. In addition, the sealing device must cope with side effects related to higher interface speeds, rotordynamics issues, or durability. Brush seals main assets are their excellent leakage performance with low friction properties compared to other contact seals like lip seals, and their ability to withstand rotor radial excursion without permanent damage. However, proper design optimization cannot be performed without the inclusion of the tribological performance. This paper presents a parametric investigation of the friction properties of carbon fibre brush seals as a function of the fibre pack geometry and the rotational speed. Carbon fibre and commonly used metallic brush seals present fundamentally different behaviour in presence of differential pressure or rotational speed. This paper also proposes an alternative method to predict the brush seal torque, based on measurements with a torque sensor. Heat generation was also evaluated with a thermographic camera. Both methods ensured consistency between results.

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“…A limited number of research works have been performed on this field, the most notorious ones being mostly focused on heat generation properties (4) , or their suitability to oil mist applications (5) , but to this day, no parametrical studies on leakage or tribological performance have been performed yet. The most common approach is to simulate the bristle pack behaviour as a porous medium (6)(7)(8) , and more recently, parametrical studies have been performed using CFD tools (10,11) . It was found that the fence height was the most important parameter influencing the leakage rate amongst the free height and the thickness.…”

Section: Introductionmentioning

confidence: 99%

Experimental characterisation of carbon fibre brush seal leakage performance as a function of bristle pack geometrical parameters under dry conditions

Outirba

Hendrick

Nicolas³

2017

Aeronaut. j.

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Over the last decades, it has been progressively acknowledged that reducing the specific fuel consumption and the emission of pollutants, as well as improving the thrust-to-weight ratio involves extensive research on advanced sealing technologies. Amongst these, brush seals are particularly well considered for their excellent leakage performance, their low friction properties, and their ability to cope with inevitable rotor excursions during flights. This paper presents the experimental work that has been carried on in order to characterise carbon fibre brush seals leakage rate in function of the bristle pack geometry, under different pressure loads and rotational speeds. The analysed parameters are the bristle-free length, the density and the inter-plate distance. The work, performed by the ULB (Université Libre de Bruxelles) in collaboration with French engine manufacturer Safran Aircraft Engines, highlights specific behaviour of carbon fibre brush seals under differential pressure, proposes a leakage prediction model developed through empirical equations, and discusses over the most influential parameters that influence the air consumption of a brush seal.

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Effects of Clearance on Leakage Flow Characteristics of Labyrinth Brush Seal

Cited by 3 publications

References 14 publications

Flow Conditioning to Control the Effects of Inlet Swirl on Brush Seal Performance in Gas Turbine Engines

Flow Conditioning to Control the Effects of Inlet Swirl on Brush Seal Performance in Gas Turbine Engines

Experimental characterization of friction and heat generation of carbon fibre brush seals for aero-engines

Experimental characterisation of carbon fibre brush seal leakage performance as a function of bristle pack geometrical parameters under dry conditions

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