Leakage reduction by optimisation of the straight–through labyrinth seal with a honeycomb and alternative land configurations

Wróblewski, Włodzimierz; Frączek, Daniel; Marugi, Krzysztof

doi:10.1016/j.ijheatmasstransfer.2018.05.070

Cited by 30 publications

(13 citation statements)

References 20 publications

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“…The fins are inclined towards the inflow. The dimensions of the labyrinth as well as of the land structure can be found in [22]. The analysed labyrinth configurations included a variety of load (pressure ratio) and clearance size, but the nominal operation point was for  = 1.16 and clearance s = 0.75 mm.…”

Section: Investigated Geometriesmentioning

confidence: 99%

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Experimental and numerical tip leakage flow visualization in the LP turbine labyrinth seal

et al. 2019

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The subject of this publication is the identification of basic flow parameters and flow structures in the seal experimentally and compare them with CFD results. A straight-through seal with two leaning fins and smooth or honeycomb land was analysed. The sealing concept is characteristic for the tip seal of the last stage of an aircraft low-pressure turbine. Due to the limitations of the test rig the analyses presented here were conducted on a highly simplified, stationary model of the seal itself, with an axial inflow and no curvature in the circumferential direction. The characteristics of the discharge coefficient as a function of the pressure ratio for different clearances and the pressure distribution along the seal, for different pressure ratios are presented. In addition, an attempt was made to visualize the flow using the schlieren technique. The main idea of application schlieren photography was to observe the vortex and separation structures occurring during the flow through the labyrinth seal, which is the major source of pressure losses. CFD calculations were carried out using the Ansys CFX commercial code.

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Section: Investigated Geometriesmentioning

confidence: 99%

“…The studies presented here were a part of the research of the rotor tip seal of the low-pressure part of an aircraft engine turbine. Some parts of the research were described in [20][21][22][23]. The main goal of the research was to improve the efficiency of the analysed seal.…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical tip leakage flow visualization in the LP turbine labyrinth seal

et al. 2019

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“…It was confirmed that the MLS had about 30% less leakage performance than an SLS. Wroblewski et al [25] suggested an optimal geometry of four labyrinth seals with different geometrical land configurations (solid land, honeycomb, squeezed honeycomb, and rhomboid). Jia et al [26] proposed a staggered seal using T-shaped teeth (TLS) and compared the leakage with those of conventional straight and staggered seals through computational analysis.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Leakage Characteristics of a Stepped Labyrinth Seal with a Ribbed Casing

2021

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A new type of stepped seal with a ribbed casing is proposed to efficiently reduce the leakage at the tips of turbine blades. The leakage characteristics of two different types of labyrinth seals (conventional seal vs. ribbed seal) were compared and analyzed through computational fluid dynamics (CFD) in a wide operating range of pressure ratios and clearances. The analysis showed that the ribbed seal has superior leakage performance to the conventional seal at all clearance sizes. With the same clearance size (S/H = 1.0), the flow function of the ribbed seal was approximately 21.5–42.6% less than that of the conventional seal. Also, different trends of variation in the flow function according to the increase of the clearance were found between the conventional and ribbed seals. The leakage flow inside the labyrinth seal was analyzed to explain the cause of this difference in tendency, and it was confirmed that the added ribs cause collision between the leakage flow and the tooth wall, even with the increase of the clearance. Also, the ribbed seal enables operation at a larger clearance with the same leakage performance when comparing the absolute leakage flow rate of the two seals. In addition, a parametric study on the influence of the rib height and rib inclination angle revealed that the flow function generally decreases as both parameters increase.

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“…The Computational Fluid Dynamics (CFD) method was adopted to study the influence of structural and operation parameters on tangential friction coefficients by Wu [9] and the leakage performance of four LS configurations was also studied [10]. Wlodzimierz [11] optimized the structural variables of LS with honeycomb holes and achieved a reduction in leakage. Parametric research on a type of LS with honeycomb holes was conducted by Kali [12] and the influence of honeycomb size, pressure ratio and clearance on performance was obtained.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Flow Characteristics and Aerodynamic Performance of a 1.5-Stage SCO2 Axial-Inflow Turbine with Labyrinth Seals

Zhang

2020

Applied Sciences

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The leakage problem of supercritical carbon dioxide (SCO2) axial-inflow turbine brings great challenges to the efficiency and security of the power system. Labyrinth seals are usually utilized to improve the leakage characteristics of the blade tip. In this paper, a 1.5-stage SCO2 axial-inflow turbine is established and labyrinth seals are arranged on the top of the first stage stator and rotor blades. The effects of seal clearance, groove on seal cavity surface and circle groove shape on flow characteristics and aerodynamic performance under different pressure ratio are investigated. Increasing seal clearance can significantly weaken the turbine performance. Arranging rectangle, circle and V-shaped grooves on the seal cavity surface near the outlet of the seal gap can enhance the energy dissipation, reduce the relative leakage and improve the power and efficiency. Increasing the groove width can improve the aerodynamic performance while the effect of the groove depth is weak. The configuration where the circle groove width is 50% of the pitch of seal tooth achieves the best performance with the relative leakage of stator1 and rotor, power and efficiency of 6.04 × 10−3, 8.09 × 10−3, 3.467 MW and 86.86% respectively. With an increase in pressure ratio, the relative leakage increases firstly and then remains almost constant. The power increases while the efficiency increases firstly and then decreases, reaching the peak value under the design condition.

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Leakage reduction by optimisation of the straight–through labyrinth seal with a honeycomb and alternative land configurations

Cited by 30 publications

References 20 publications

Experimental and numerical tip leakage flow visualization in the LP turbine labyrinth seal

Experimental and numerical tip leakage flow visualization in the LP turbine labyrinth seal

A Study on the Leakage Characteristics of a Stepped Labyrinth Seal with a Ribbed Casing

Numerical Investigation on Flow Characteristics and Aerodynamic Performance of a 1.5-Stage SCO2 Axial-Inflow Turbine with Labyrinth Seals

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