Topic
Tip clearance
About: Tip clearance is a research topic. Over the lifetime, 2637 publications have been published within this topic receiving 32671 citations.
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11 Jun 1990
TL;DR: In this article, the authors used linear cascade experimental data as though it were a rotor with work transfer and found that radiused geometry, contoured to shed radial flow into the gap and reduce the leakage mass flow, was found to have a significantly higher efficiency.
Abstract: To assess the possibility of tip clearance loss reduction and to explore the nature and origin of tip clearance loss, blade tip geometries which reduce the roughly 40% of total loss occurring within the gap were studied. The shapes investigated aimed at reducing or avoiding the gap separation bubble thought to contribute significantly to both internal gap loss and to the endwall mixing loss. It was found that radiusing and contouring the blade at gap inlet eliminated the separation bubble and reduced the internal gap loss but created a higher mixing loss to give almost unchanged overall loss coefficients when compared with the simple sharp edged flat tipped blade. The separation bubble does not therefore appear to influence the mixing loss. Using a method of assessing linear cascade experimental data as though it were a rotor with work transfer, one radiused geometry, contoured to shed radial flow into the gap and reduce the leakage mass flow, was found to have a significantly higher efficiency. This demonstrates the effectiveness of the data analysis method and that cascade loss coefficient alone or gap discharge coefficient cannot be used to accurately evaluate tip clearance performance. Contouring may ultimately lead to better rotor blade performances.Copyright © 1990 by ASME
22 citations
01 Jul 1999
TL;DR: In this article, a computational study has been performed to predict the distribution of convective heat transfer coefficient on a simulated blade tip with cooling holes, and the results showed that the uniformity of wetting of the surface by the film cooling jet is helped by the reverse flow due to edge separation of the main flow.
Abstract: A computational study has been performed to predict the distribution of convective heat transfer coefficient on a simulated blade tip with cooling holes. The purpose of the examination was to assess the ability of a three-dimensional Reynolds-averaged Navier-Stokes solver to predict the rate of tip heat transfer and the distribution of cooling effectiveness. To this end, the simulation of tip clearance flow with blowing of Kim and Metzger was used. The agreement of the computed effectiveness with the data was quite good. The agreement with the heat transfer coefficient was not as good but improved away from the cooling holes. Numerical flow visualization showed that the uniformity of wetting of the surface by the film cooling jet is helped by the reverse flow due to edge separation of the main flow.
22 citations
Patent•
24 Nov 2015TL;DR: In this paper, a turbine shroud assembly or blade track assembly adapted to extend around a turbine wheel assembly is disclosed, which includes a carrier and a blade track coupled to the carrier.
Abstract: A turbine shroud assembly or blade track assembly adapted to extend around a turbine wheel assembly is disclosed. The turbine shroud assembly includes a carrier and a blade track coupled to the carrier. The blade track is movable between a radially-inward position having a first inner diameter and a radially-outward position having a second inner diameter larger than the first inner diameter.
22 citations
TL;DR: In this paper, a noncontact sensor with a precision of 30μm was developed to measure tip clearance in a turbine rig assembled in a wind tunnel and tested in two distinct turbines with the aim of minimizing the effect of the noise on the repeatability of the measurements.
Abstract: Tip clearance is critical to the performance of rotating turbomachinery. The objective of this paper is to develop a noncontact sensor with a precision of 30 μm to measure tip clearance in a turbine rig assembled in a wind tunnel. To carry out the measurements, an optical sensor whose main component is a bundle of optical fibers is employed. We use four different configurations of this sensor, which are tested in two distinct turbines with the aim of minimizing the effect of the noise on the repeatability of the measurements. Each configuration serves to increase the precision until the required performance is achieved for the measurement of the tip clearance. Our results may be helpful to develop applications related to structural health monitoring or active clearance-control systems.
22 citations
Patent•
16 Mar 1993
TL;DR: In this paper, a method and a device for controlling the blade tip clearance in a rotating machine where the machine comprises a turbine part and a compressor part separate from the turbine part is presented.
Abstract: A method and a device for controlling the blade tip clearance in a rotating machine where the machine comprises a turbine part (1) and a compressor part (4) separate from the turbine part. The stator housing (15) of the turbine part is formed with a stator cone (16). The invention is characterized in that one or more bladed (5) turbine discs (2), during non-steady operation, for example during start-up, stop and load changes, are moved out of the stator cone such that the blade tip clearance is increased and that the turbine discs during continuous operation are moved into the stator cone such that the blade tip clearance is reduced.
22 citations