Rolls-Royce Motor Cars

About: Rolls-Royce Motor Cars is a based out in . It is known for research contribution in the topics: Turbine & Gas compressor. The organization has 3845 authors who have published 4934 publications receiving 58973 citations. The organization is also known as: Rolls-Royce Motor Cars Limited.

A contribution to the understanding and prediction of jet noise generation in forced mixers

Abstract: In recent work on coplanar, coaxial jet noise prediction, single stream noise methods have been successfully employed to predict the noise contribution of each region of the jet plume and the results summed to calculate the total far-field noise spectrum. The objective of the present work is to extend this approach to the ‘buried’ nozzle configurations, in which initial mixing is constrained within a short pipe before both flows exit through a common nozzle. Two basic configurations are considered, the unforced, annular or confluent mixer, in which the primary nozzle is of circular cross-section and the lobed or forced mixer, in which the primary nozzle is of lobed form designed to promote more rapid mixing between the primary and secondary flows prior to the final nozzle. For the annular configuration very little mixing takes place between the primary and final nozzle exit planes. The mixing takes place externally, and the noise is consistent with the acoustic modelling described previously. The lowest frequencies are controlled by the fully mixed flow, while the remainder of the spectrum is due to the ‘effective jet’, that is the free mixing of the primary and secondary flows. For the forced or lobed mixer, the noise reduction at low frequencies, relative to the annular, is due to the fact that the primary flow has almost ‘mixed out’ prior to the final nozzle; an observation confirmed by aerodynamic surveys. The low frequency decrease is therefore limited to the levels of noise anticipated for the fully mixed flow. The penalty paid for forced mixing is an increase in noise at higher frequencies, which increases with increased penetration. The spectrum of this forced mixer noise source appears to correlate with the mixed jet Strouhal number and velocity, except for the highest Mach number condition, where an additional source is identified, termed the ‘high Mach number lift’. An initial modelling of the forced mixer noise source is presented, based on a mixed jet with an enhanced turbulence level, which is in reasonable agreement with the measured data.

From blue skies to green skies: engine technology to reduce the climate-change impacts of aviation

Abstract: The environmental challenge facing the aerospace industry is a significant one. Despite consistent, continued efforts by industry to reduce the fuel burn, emissions and noise produced by aircraft, concern over climate change means that further advances in technology are required to mitigate the climate impacts of aviation. This paper outlines the current status of the industry, the current understanding of aviation's climate impacts and technology's progress to environmental targets, before investigating opportunities for further emissions reductions. These include technologies to improve the engine's propulsive and thermal efficiencies, technologies enabling reduced thrust requirements and alternative fuels. This paper discusses how Rolls-Royce's Technology Strategy, ‘Rolls-Royce Technology Visions’, enables these innovative technologies to be brought to market, the timescales and challenges associated with their development, and the partnership required between industry and government.

A nozzle guide vane structure for a gas turbine engine

Abstract: A nozzle guide vane structure for a gas turbine engine in which the vane comprises an aerofoil portion and inner and outer platforms. The non gas-contacting surfaces of the platforms are provided with forward and rearward sealing flanges sealed to adjacent engine structure to provide spaces sealed against ingress of working fluid between each pair of forward and rearward flanges. The mounting means for the vane projects into these spaces from the non gas-contacting surface.

Apparatus for premixing in a gas turbine engine

Abstract: An apparatus for mixing fuel with oxidizing agent is disclosed comprising an outer body and an inner body. The outer body has an interior surface extending between an inlet end toward an outlet end. The interior surface includes a first plurality of openings. The inner body has an exterior surface extending between the first end and the second end of the inner body. The exterior surface of the inner body includes a second plurality of openings. At least a portion of the exterior surface of the inner body is positioned within the outer body to define a mixing channel between the exterior surface of the inner body and the interior surface of the outer body. In one form the first and second plurality of openings substantially longitudinally span at least one of the outer body and the inner body. In another form the first and second plurality of openings are substantially radially oriented. In yet another form the first and second plurality of openings are offset from one another.