Computational and experimental investigations are carried out to estimate leakage flow rate in a static straight-through labyrinth seal. Tests were conducted over a range of pressure ratios, varying from 1.003 to 1.897, for three clearance values of 0.2, 0.36 and 0.6 mm respectively. The measured values of leakage flow parameter are corroborated with the results obtained from the simulations using FLUENT computer package. The agreement was within 8.6%. The flow details, e.g., the stream line pattern, velocity vectors, static pressure and turbulent kinetic energy in a typical seal passage, are presented. © 1997 by ASME.

B. V.S.S.S. Prasad

Department of Mechanical Engineering

Aircraft engines

Gas turbines

Heat transfer

Kinetic energy

Kinetics

Leakage (fluid)

CLEARANCE VALUE

COMPUTER PACKAGES

Experimental investigations

LEAKAGE FLOW RATE

Measured values

Static pressure

Turbulent kinetic energy

Velocity vectors

Seals

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Computational and Experimental Investigations of Straight-Through Labyrinth Seals

Proceedings of the ASME Turbo Expo

Radial growth predictions of rotating labyrinth seals are conventionally obtained from one-dimensional analytical models. However, these predictions quantitatively differ within themselves by about 5-500%. Simulations using three-dimensional finite element method (FEM) are carried out in this paper for a typical labyrinth seal, subjected to high rotational speed and temperature, for a range of radius-to-length ratio of the rotor. Taking the predicted values by FEM as reference, four analytical models are assessed and their errors are quantified. These errors are found to be independent of rotational speed and temperature but significantly vary with the radius-to-length ratio of the rotor. Based on this finding, simple analytical models, together with correction factor charts, are suggested. © 2018 Walter de Gruyter GmbH, Berlin/Boston.

International Journal of Turbo and Jet Engines

Assessment of Analytical Predictions for Radial Growth of Rotating Labyrinth Seals

Leakage characteristics, influenced by centrifugal and thermal radial growth are determined computationally for a generic rotating labyrinth seal used in the gas turbine secondary air system. Three seal locations, namely, R25, R50 and R75 are represented by means of varying the rotor radius mimicking different radial positions of the seal from the shaft axis. The combined influence of seal location and its radial (Centrifugal and thermal) growth on the leakage performance is investigated for a wide-ranging speeds from 1000 to 3000 rad/s, temperatures ranging from 200 to 450 °C and pressure ratios varying from 1.1 to 2.5, for a chosen initial clearance of 500 micron. A comparison of the effect of rotation and temperature gradient among different rotors shows that the radial growth and leakage flow rates significantly vary with the increasing radius. © 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

Journal of Mechanical Science and Technology

Influence of combined radial location and growth on the leakage performance of a rotating labyrinth gas turbine seal

A computational methodology is proposed to predict the running clearance of a six-tooth straight-through rotating labyrinth seal numerically by taking into account both the centrifugal and thermal growths. Four different angular velocities ranging from 0 to 3000 rad/s are chosen to study the influence of rotation on the leakage flow rate. The detailed leakage flow fields and the structural deformations are presented. Further, different pressure ratios in the range of 1.1 to 2.5 have been investigated for a wide range of initial clearances. The methodology is validated against the available data in the literature. It is found out that there is a significant reduction in leakage flow rate by incorporating the radial growth for a particular operating condition. However, for a given initial clearance, the rotation has negligible effect on the reduction in the leakage flow rate, except at pressure ratios lower than 1.7. Further; the rotation has more prominent effect for smaller clearance values. Copyright © 2013 by ASME.

Performance analysis of a rotating labyrinth seal with radial growth

Sodium cooled Fast Breeder Reactors (FBR) form the second stage of India's Nuclear power programme. Through a narrow annular space in the grid plate assembly of a prototype FBR, a very low leakage flow of liquid metal sodium should pass, experiencing a stipulated high pressure drop, and without much cavitation. To achieve this, a suitable labyrinth seal is required to be developed for use in the annulus. Water is employed as the model testing liquid which is estimated to experience a pressure drop ratio of 10.5 at the rated leakage flow. Previously studied circular or sinusoidal-grooved square, triangular or curved cavity labyrinth seals were unable to meet this value. In the present work, Computational Fluid Dynamics (CFD) analyses are carried out on Helical-grooved Square cavity Labyrinth Seals (HSLS), using commercial code Fluent. It is found that the geometrical configuration of the grooves plays a major role on the pressure drop. Experimental results reveal close agreement with CFD predictions. An optimal configuration of this square cavity seal is identified by applying genetic algorithm (GA) using commercial packages. It meets just about 24% of the targeted value. Later, using parametric CFD analyses, a Helical-grooved Triangular cavity Labyrinth Seal (HTLS) and different Helical-grooved Curved cavity Labyrinth Seals (HCLS) are analysed. The most favourable profile is tested and found to reach the required pressure drop. CFD cavitation analyses predict the intensity of cavitation in these seals to be below prohibitive levels. © 2011 Elsevier B.V. All rights reserved.

Nuclear Engineering and Design

Pressure drop and cavitation investigations on static helical-grooved square, triangular and curved cavity liquid labyrinth seals

Polish Maritime Research

A method of diagnosing labyrinth seals in fluid-flow machines

Journal of Turbomachinery

Windage Heating of Air Passing Through Labyrinth Seals

Tribology Transactions

Labyrinth Seal Leakage Resistance and Visualization Experiments in a Novel, Variable-Configuration Facility

A New Approach for Stabilizing Labyrinth Seal Leakage

Importance of Labyrinth Seal Through-Flow Deflection for Enlarging Clearance Without Increasing Leakage

Computational and experimental investigations of straight -through labyrinth seals

Journal	Proceedings of the ASME Turbo Expo
Publisher	American Society of Mechanical Engineers (ASME)
Open Access	Yes