Experimental Study of Temperature Effect on Labyrinth Seal Leakage and Vibration Characteristics of Rotor
01 Jan 2021-pp 227-236
TL;DR: In this article, the effect of thermal growth of labyrinth seal on the leakage flow rates and effect on vibration characteristics of the system is evaluated. But the main design concern is to prevent the seal rub with the stator in the range of operating conditions and to control the system rotordynamics.
Abstract: Labyrinth seals are the most widely used non-contact-type turbine seals. The main design concern is to prevent the seal rub with the stator in the range of operating conditions and to control the system rotordynamics. This work aims at experimentally evaluating the effect of thermal growth of labyrinth seal on the leakage flow rates and effect on vibration characteristics of the system. An experimental seal test rig for teeth on rotor (TOR)-type straight labyrinth seal with four flat tip teeth has been developed. Constant clearance between seal and stator is maintained and tested at different speeds and temperatures by varying the inlet air pressure. Leakage results are compared for the seal for the range of operating conditions and for a given seal radial clearance. In addition, vibration data are measured at various locations to understand the influence of seal on the vibration characteristics of the rotor system. It is seen that flow leakage rate and vibration of system are influenced by the pressure difference and the temperature.
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TL;DR: In this paper, heat transfer and leakage loss measurements were obtained for compressible flows in typical straight-through labyrinth seals with high rotational speeds, and the experiments were an extension of earlier measurements in a stationary test facility.
Abstract: Heat transfer and leakage loss measurements were obtained for compressible flows in typical straight-through labyrinth seals with high rotational speeds. The experiments are an extension of our earlier measurements in a stationary test facility. In order to ensure direct comparisons to the original experiments, the principal dimensions of the test facility and gas dynamic parameters of the hot gas were kept similar. The new study encompasses a wide range of Taylor numbers, Reynolds numbers, and clearances between the rotating annular fins and the stationary shroud
77 citations
TL;DR: In this paper, an experimental test facility is used to measure the leakage and rotordynamic coefficients of teeth-on-rotor and teethon-stator labyrinth gas seals.
Abstract: An experimental test facility is used to measure the leakage and rotordynamic coefficients of teeth-on-rotor and teeth-on-stator labyrinth gas seals. The test results are presented along with the theoretically predicted values for the two seal configurations at three different radial clearances and shaft speeds to 16,000 cpm. The test results show that the theory accurately predicts the cross-coupled stiffness for both seal configurations and shows improvement in the prediction of the direct damping for the teeth-on-rotor seal. The theory fails to predict a decrease in the direct damping coefficient for an increase in the radial clearance for the teeth-on-stator seal.
75 citations
37 citations
TL;DR: In this paper, a generic rotating labyrinth seal used in the gas turbine secondary air system was 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.
Abstract: 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.
18 citations