Leakage and rotordynamic performance of T type labyrinth seal

Jia, Xingyun; Zheng, Qun; Jiang, Yuting; Zhang, Hai

doi:10.1016/j.ast.2019.02.043

Cited by 28 publications

(12 citation statements)

References 22 publications

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“…The sealing ring was made into various zigzag shapes to increase the loss of local kinetic energy, so as to reduce leakage flowrate [12]. One of the most common research was to compare the sealing effect of different sealing types, such as straight-through, stepped, and labyrinth types [13][14][15]. The other was to explore the influence of sealing size on the clearance leakage and unit efficiency [16,17].…”

Section: Introductionmentioning

confidence: 99%

Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine

Hou

Cheng

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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The clearance flow of pump-turbine has significant influence on hydraulic forces of the runner, which is related to safety of the unit. To clarify the influence factors, clearance flowrate and clearance hydraulic axial force of a prototype pump-turbine were analyzed by 3D CFD simulations. The results show that the rotational speed, and the smallest radial sizes of clearance inlet, outlet, and the seal ring sizes are the determinant factors for clearance leakage flowrate, while the rotational speed and the radial size at clearance inlet are the major factors for clearance axial force. The rotational speed of rotating surfaces mainly affects the strength of rotating shear flow, while geometric sizes mainly affect the hydraulic loss of leakage flow. By assuming that the clearance region as several ring pipes, we obtained the simplified calculation formulas for estimating clearance leakage flowrate and clearance axial force. The flowrate can be expressed as a function of the water head difference across the clearance region, the rotational speed, and the sizes of clearance inlet, outlet and sealing ring, while the clearance axial force is a function of the inlet pressure and the square of both radius and rotational speed. The formula calculations agree with the numerical simulations well. This paper can provide a reference for runner clearance size design.

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Section: Introductionmentioning

confidence: 99%

Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine

Hou

Cheng

et al. 2022

IOP Conf. Ser.: Earth Environ. Sci.

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“…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. Compared to the straight seal, leakage decreased by 23-25%, but compared to the staggered seal, leakage increased by 7-8%.…”

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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“…Wu 6 analyzed the influence of geometric and operating parameters on the friction coefficients. A T-type labyrinth seal tooth was proposed by Jia 7 to reduce the leakage. Yuan 8 carried out the simulation on flow characteristics of the SCO 2 labyrinth seal and compared with experimental results.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on the performance of impeller back seal configuration in a supercritical CO₂ radial-inflow turbine

Wang

Zhang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Radial-inflow turbine is a core component in supercritical CO2 (SCO2) Brayton cycle. The leakage from the nozzle outlet towards the impeller back brings a great challenge to the efficiency and security of the power system. In this paper, the labyrinth seal (LS) and dry gas seal (DGS) are arranged on the impeller back of a SCO2 radial-inflow turbine and the influence on the comprehensive performance is investigated. Results demonstrate that both LS and DGS configurations can significantly reduce leakage of the impeller back and DGS configuration performs better. Compared with the configuration without leakage, the power and efficiency of DGS configuration are only reduced by 0.27% and 0.35% respectively. The seal clearance and the inlet width have a greater effect on LS configuration. The thermo-mechanical seal deformation values of DGS configurations are all less than 8 μm, which verifies the feasibility. Finally, a novel combined seal configuration with both LS and DGS is proposed and excellent performance is achieved, providing a potential approach for the sealing problem of SCO2 radial-inflow turbine.

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Leakage and rotordynamic performance of T type labyrinth seal

Cited by 28 publications

References 22 publications

Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine

Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine

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

Numerical investigation on the performance of impeller back seal configuration in a supercritical CO₂ radial-inflow turbine

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Leakage and rotordynamic performance of T type labyrinth seal

Cited by 28 publications

References 22 publications

Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine

Influence factors of clearance leakage flowrate and clearance hydraulic axial force of pump-turbine

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

Numerical investigation on the performance of impeller back seal configuration in a supercritical CO2 radial-inflow turbine

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Numerical investigation on the performance of impeller back seal configuration in a supercritical CO₂ radial-inflow turbine