Comparison of leakage performance and fluid-induced force of turbine tip labyrinth seal and a new kind of radial annular seal

Zhang, Wanfu; Yang, Jiangang; Li, Chun; Tian, Yu

doi:10.1016/j.compfluid.2014.09.010

Cited by 23 publications

(12 citation statements)

References 16 publications

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“…Leak-tightness of the seal depends on such features of the seal geometry as pitch, length and height of the chamber (Zhang et al 2014, Wang et al 2007, Joachimiak and Krzyślak 2019, Szymanski et al 2018, Lampart, 2009. Of significant impact on the seal leak-tightness is its wear, Joachimiak and Krzyślak (2017).…”

Section: Introductionmentioning

confidence: 99%

Universal Method for Determination of Leakage in Labyrinth Seal

Joachimmiak

2020

JAFM

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This paper presents calculation model enabling determination of the leakage rate in labyrinth seals. Described model is based on the Saint-Venant equation. It includes a new type of flow coefficient, which was determined based on experimental tests and described depending on the Reynolds number and the radial clearance. The structure of this calculation model can be applied to determine the leakage rate in straight through, staggered labyrinth seals as well as with various number of clearances. This model enables determining distribution of thermodynamic and flow parameters of the gas along the seal length. Results obtained from this model were next compared with experimental data for various types of seals. It enabled determination of kinetic energy carry-over coefficient in geometries under investigation. The value of this coefficient was then compared with the value of the coefficient from the Scharrer's, Neumann's and Hodkinson's models. Obtained results indicate that the value of the kinetic energy carry-over coefficient depends not only on the seal geometry, but also on the pressure decrease.

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Section: Introductionmentioning

confidence: 99%

Universal Method for Determination of Leakage in Labyrinth Seal

Joachimmiak

2020

JAFM

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“…The coupled analysis of LS and blade was also conducted by plenty of scholars. Giboni [15] studied the mixing effect of flows in leakage passage and cascade when the LS was arranged on the top of the rotor blade. The results agreed utterly with the test data.…”

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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“…The presented investigations were related to the geometry of the straight-through labyrinth seal of different configuration and number of sealing teeth. Zhang et al (2014) made CFD calculations of the over-shroud seal of an axial turbine. The calculations were performed for the geometry of a two-tooth straight-through labyrinth seal.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Gas Flow in a Labyrinth Seal of Variable Pitch

Joachimmiak

Krzyślak

2019

JAFM

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The paper discusses the results of investigations performed for the segments of straight-through labyrinth seals of constant length. Increasing the number of teeth of a segment resulted in a reduction of the pitch length to obtain the slot seals. The phenomena occurring during gas flow in labyrinth and slot seals differ significantly. They are described with different calculation models. The analysis presented in this paper is related to the change of the tightness and the nature of the flow from a straight-through labyrinth seal to a slot seal. The paper includes the results of experimental research and CFD calculations. Models applied for the Neumann and Scharer labyrinth seals as well as the model of the Salzman and Fravi slot seals were discussed. For the Neumann and Scharer models, correction coefficients for the tested geometry were proposed. Based on the assumptions for the said models and the obtained results, the phenomena responsible for the minimization of the leakage were discussed. The leakage rate in segments of different gap heights depending on the number of teeth and the pressure ratio upstream and downstream of the segment has been analyzed. Based on the experimental data, an optimum number of teeth in the segment for minimum leakage was determined. CFD calculations allowed determining the minimum leakage geometry. The experimental data contained in this paper confirm that the determined optimum pitch range is independent of the pressure drop.

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Comparison of leakage performance and fluid-induced force of turbine tip labyrinth seal and a new kind of radial annular seal

Cited by 23 publications

References 16 publications

Universal Method for Determination of Leakage in Labyrinth Seal

Universal Method for Determination of Leakage in Labyrinth Seal

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

Analysis of the Gas Flow in a Labyrinth Seal of Variable Pitch

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