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.

Optical monitoring method and apparatus

Abstract: Monitor signals are produced which are qualitative or quantitative measures of the shape, size or position of a light spot on an optical head relative to fibre-optic receptors in the optical head. One pair or two pairs of receptors may be used. Production of the monitor signals involves modulating the incident light forming the light spot at a predetermined frequency, delaying the light signals in one or more of the fibre-optic receptors relative to the light signals in one or more of the other receptors by, say half a wavelength of the predetermined frequency, combining the outputs of the fibre-optic receptors to produce a compound light signal, producing an equivalent compound electrical signal by means of a photodiode, and processing the compound electrical signal in electronic processors to extract one or more of its components to act as the monitor signals. Use of the invention is particularly in the monitoring of relative displacements involving optical systems which image a light source on one object onto an optical head on another object, thereby forming the light spot whose shape, size, or position alters according to the relative displacement between the two objects and the type of optical system used.

Gas Turbine Rotor Blade Film Cooling With and Without Simulated NGV Shock Waves and Wakes

Abstract: Detailed heat transfer measurements have been made around a film-cooled transonic gas turbine rotor blade in the Oxford Isentropic Light Piston Tunnel. Film cooling behaviour for four film cooling configurations has been analysed for a range of blowing rates both without and with simulated nozzle guide vane (NGV) shock wave and wake passing. The superposition model of film cooling has been employed in analysis of time-mean heat transfer data, while time resolved unsteady heat transfer measurements have been analysed to determine interaction between film-cooling and unsteady shock wave and wake passing. It is found that there is a significant change of film-cooling behaviour on the suction surface when simulated NGV unsteady effects are introduced.© 1990 ASME

Multibladerow Forced Response Modeling in Axial-Flow Core Compressors

Abstract: This paper describes the formulation and application of an advanced numerical model for the simulation of blade-passing and low-engine order forced response in turbomachinery core compressors. The Reynolds averaged Navier-Stokes equations are used to represent the flow in a nonlinear time-accurate fashion on unstructured meshes of mixed elements. The structural model is based on a standard finite-element representation. The fluid mesh is moved at each time step according to the structural motion so that changes in blade aerodynamic damping and flow unsteadiness can be accommodated automatically. A whole-annulus 5-bladerow forced response calculation, where three upstream and one downstream bladerows were considered in addition to the rotor bladerow of interest, was undertaken using over 20 million grid points. The results showed not only some potential shortcomings of equivalent 2-bladerow computations for the determination of the main blade-passing forced response, but also revealed the potential importance of low engine-order harmonics. Such harmonics, due to stator blade number differences, or arising from common symmetric sectors, can only be taken into account by including all stator bladerows of interest. The low engine-order excitation that could arise from a blocked passage was investigated next. It was shown that high vibration response could arise in such cases.

Sprung brush seals

Abstract: A brush seal is formed by bristles tightly packed between two annular sideplates having different inner radii and secured to a housing. The free ends of the bristles are in rubbing contact with a shaft. The differential pressure which the seal can support is increased by loading the bristles against the annular sideplate having the smaller inner radius, the loading force being such that the bristles can still move in the plane of the seal. As a result the amount of relative movement of shaft and housing that the seal can tolerate is not reduced.