Rolls-Royce Holdings

About: Rolls-Royce Holdings is a company organization based out in Derby, United Kingdom. It is known for research contribution in the topics: Turbine & Gas compressor. The organization has 4027 authors who have published 6305 publications receiving 80517 citations. The organization is also known as: Rolls-Royce Holdings plc.

Blade tip clearance control

Abstract: The invention is particularly concerned with the control of blade tip clearance in high pressure compressors of gas turbine engines. The compressor comprises a rotor assembly having radially extending rotor blades and a stator assembly. The stator assembly comprises an inner casing and a cylindrical wall member spaced radially from the inner casing to form a chamber. The axial ends of the cylindrical wall member seal with and are moveable radially with respect to the inner casing. The casing has radially inner and radially outer stops to limit radial movement of the cylindrical wall member. The cylindrical wall member carries a ring of shroud segments which are spaced radially from the rotor blades by a clearance. A valve supplies relatively high pressure air from the downstream end of the compressor into the chamber to contract the cylindrical wall member onto the inner stops to give optimum clearance during cruise, or connects the chamber to relatively low pressure air in the fan duct by aperture in outer casing by pipes to allow the cylindrical wall member to expand to the outer stops to prevent rubbing during transients.

Gas turbine engine sealing arrangement

Abstract: In a sealing arrangement between two discs of a gas turbine engine a split sealing arrangement comprising a pair of sealing formations each made up of a plurality of sealing segments is provided Each of the segments has a root accommodated in serrations of the discs The roots of the sealing segments are positively connected to roots of the rotor blades by dovetail or T-shaped tongues and grooves The sealing segments are also provided with internal cooling passages

Development of Blade Profiles for Low Pressure Turbine Applications

Abstract: This paper describes a programme of work, largely experimental, which was undertaken with the objective of developing an improved blade profile for the low-pressure turbine in aero-engine applications.Preliminary experiments were conducted using a novel technique. An existing cascade of datum blades was modified to enable the pressure distribution on the suction surface of one of the blades to be altered. Various means, such as shaped inserts, an adjustable flap at the trailing edge, and changing stagger were employed to change the geometry of the passage. These experiments provided boundary layer and lift data for a wide range of suction surface pressure distributions. The data was then used as a guide for the development of new blade profiles. The new blade profiles were then investigated in a low-speed cascade that included a set of moving bars upstream of the cascade of blades 10 simulate the effect of the incoming wakes from the previous blade row in a multistage turbine environment.Results are presented for two improved profiles that are compared with a datum representative of current practice. The experimental results include loss measurements by wake traverse, surface pressure distributions, and boundary layer measurements. The cascades were operated over a Reynolds Number range from 0.7 × 105 to 4.0 × 105. The first profile is a “laminar flow” design that was intended to improve the efficiency at the same loading as the datum. The other is a more highly loaded blade profile intended to permit a reduction in blade numbers. The more highly loaded profile is the most promising candidate for inclusion in future designs. It enables blade numbers to be reduced by 20%, without incurring any efficiency penalty. The results also indicate that unsteady effects must be taken into consideration when selecting a blade profile for the low-pressure turbine.Copyright © 1996 by ASME