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.

Influence of Surface Roughness on Heat Transfer and Effectiveness for a Fully Film Cooled Nozzle Guide Vane Measured by Wide Band Liquid Crystals and Direct Heat Flux Gauges

Abstract: The influence of surface roughness on heat transfer coefficient and cooling effectiveness for a fully film cooled three-dimensional nozzle guide vane (NGV) has been measured in a transonic annular cascade using wide band liquid crystal and direct heat flux gages (DHFGs). The liquid crystal methods were used for rough surface measurements and the DHFGs were used for the smooth surfaces. The measurements have been made at engine representative Mach and Reynolds numbers and inlet free-stream turbulence intensity. The aerodynamic and thermodynamic characteristics of the coolant flow have been modeled to represent engine conditions by using a heavy foreign gas (30.2 percent SF 6 and 69.8 percent Ar by weight). Two cooling geometries (cylindrical and fan-shaped holes) have been tested. The strategies of obtaining accurate heat transfer data using a variety of transient heat transfer measurement techniques under the extreme conditions of transonic flow and high heat transfer coefficient are presented. The surfaces of interest are coated with wide-band thermochromic liquid crystals, which cover the range of NGV surface temperature variation encountered in the test. The liquid crystal has a natural peak-to-peak roughness height of 25 μm creating a transitionally rough surface on the NGV. The time variation of color is processed to give distributions of both heat transfer coefficient and film cooling effectiveness over the NGV surface. The NGV was first instrumented with the DHFGs and smooth surface tests preformed, Subsequently the surface was coated with liquid crystals for the rough surface tests. The DHFGs were then employed as the means of calibrating the liquid crystal layer. The roughness of 25 μm, which is the typical order of roughness for the in-service turbine blades and vanes, increases the heat transfer coefficient by up to 50 percent over the smooth surface level. The film cooling effectiveness is influenced less by the roughness.

Gas turbine engine with air and steam cooled turbine

Abstract: In a gas turbine engine including a turbine which has a closed cycle steam cooling system and an open cycle gas cooling system sealing arrangements are provided between adjacent pairs of turbine rotor stages. The sealing arrangement has axially extending passages to supply cooling gas from one of the turbine rotor stages to the cooling gas passages in the turbine rotor blades. Each sealing arrangement comprises a pair of sealing formations each made up of a plurality of sealing segments. Also the sealing arrangement has axially extending passages to supply steam from one of the turbine rotor stages to the steam cooling passages in the turbine rotor blades.

Calculating and communicating ensemble-based volcanic ash dosage and concentration risk for aviation

Abstract: During volcanic eruptions, aviation stakeholders require an assessment of the volcanic ash hazard. Operators and regulators are required to make fast decisions based on deterministic forecasts, which are subject to various sources of uncertainty. For a robust decision to be made, a measure of the uncertainty of the hazard should be considered but this can lead to added complexity preventing fast decision making. Here a proof-of-concept risk matrix approach is presented that combines uncertainty estimation and volcanic ash hazard forecasting into a simple warning system for aviation. To demonstrate the methodology, an ensemble of 600 dispersion model simulations is used to characterise uncertainty (due to eruption source parameters, meteorology and internal model parameters) in ash dosages and concentrations for a hypothetical Icelandic eruption. To simulate aircraft encounters with volcanic ash, trans-Atlantic air routes between New York (JFK) and London (LHR) are generated using time-optimal routing software. This approach has been developed in collaboration with operators, regulators and engine manufacturers; it demonstrates how an assessment of ash dosage and concentration risk can be used to make fast and robust flight-planning decisions even 23 when the model uncertainty spans several orders of magnitude. The results highlight the benefit of using an ensemble over a deterministic forecast and a new method for visualising dosage risk along flight paths. The risk matrix approach is applicable to other aviation hazards such as SO2 dosages, desert dust, aircraft icing and clear-air turbulence and is expected to aid flight-planning decisions by improving the communication of ensemble-based forecasts to aviation.

A composite blade

Abstract: A composite blade (26) comprises a root portion (36) and an aerofoil portion (38). The aerofoil portion (38) has a tip (42), a chord (C), a leading edge (44), a trailing edge (46), a suction surface (48) extending from the leading edge (44) to the trailing edge (46) and a pressure surface extending from the leading edge (44) to the trailing edge (46). The composite blade (26) comprises reinforcing fibres (52) in a matrix material (54). The aerofoil portion (38) adjacent the root portion (36) has regions (56, 58) at least at the leading edge (44) and trailing edge (46) comprising an asymmetric lay up of reinforcing fibres (52) and the aerofoil portion (38) adjacent the tip (42) having at least a region (62) at the mid-chord comprising an asymmetric lay up of reinforcing fibres (52).

A method, tool and system for increasing the efficiency of a design process

Abstract: The invention relates to a method, tool and system for increasing the efficiency of a design process, particularly the capture and reuse of rationale behind design decisions. A tool having an interactive graph editor is used to capture a first design rationale of a first design project, the first design rationale containing data on at least one design issue and a processing means allows the first design rationale to be identified hen the at least one design issue is encountered on a second design project. A computer and program are also described and these may be used as part of a system.