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.

Variable pressure ratio compressor

Abstract: A compressor of a gas turbine engine may have a bypass that routes a compressed air flow from within the compressor and directs the compressed air flow to a combustor. The bypass may have an inlet positioned just ahead of a downstream stage of the compressor and an outlet positioned to route the compressed air flow from the bypass to a diffuser or directly to a combustor. A valve may be used within the bypass and may be located near the inlet, near the outlet, or both. The valve may have the form of an annular sleeve in some embodiments and may be actuated with an actuator. The various arrangements allow for a compressor having a variable compression ratio.

Strategy of incorporating Ni-based braze alloy in cold sprayed Inconel 718 coating

Abstract: Ni-based superalloy (Inconel 718) and Ni-based braze alloy (MAR-M 002) composite coatings were deposited on Inconel 718 substrates via a high-pressure cold spray process. The effects of post heat treatment on microstructural evolution and chemical diffusion of the composite coatings were systematically investigated. The microstructures of the powders and composite coatings were investigated using scanning electron microscopy, electron backscatter diffraction, energy-dispersive X-ray spectroscopy and nanoindentation. After cold spray deposition, it was found that MAR-M 002 particles were uniformly distributed within the as-sprayed composite coatings. During the heat treatment process, it was noted that the diffusion of chemical species occurred across the Inconel 718 and MAR-M 002 particulate interfaces with the width of the diffusion zone being around 10 μm. The enhanced chemical diffusion between Inconel 718 and MAR-M 002 particles could effectively heal out the splat boundaries and reduce coating porosity, which was proved with the microstructure analysis. The effect of chemical diffusion on interparticle bonding strength was investigated through tensile testing. The heat-treated Inconel 718/MAR-M 002 composite coating had a tensile strength of about 810 MPa that was about 17% higher compared to the heat-treated pure Inconel 718 coating. From the SEM observations, the fractured surface of the heat-treated IN718/MAR-M 002 composite specimen was characterized by the presence of more dimples, which indicated a higher fraction of metallurgically bonded interparticle boundaries. These results demonstrated that the proposed methodology for the formation of Inconel 718/MAR-M 002 composite deposits was beneficial for improving the interparticle bonding strength in the deposits.

Turbo-electric Distributed Aircraft Propulsion: Microgrid Architecture and Evaluation for ECO-150

Abstract: This work describes the architecture and evaluation of a turbo-electric distributed propulsion microgrid for ECO-150, a NASA funded 154 passenger subsonic fixed wing commercial transport aircraft concept for entry into service by 2035. Three different microgrid types are considered: ac synchronous distribution, dc distribution, and a hybrid approach. A high level architecture for each grid type is proposed, considering requirements for single point failure accommodation, redundancy and reconfigurability, and electrical protection. Component sizing models were developed for rotating electrical machines, power converters, distribution, and protection equipment, targeting a technology readiness level (TRL) of TRL-6 by 2025. These tools are combined to evaluate the mass and efficiency metrics for each microgrid type. Sensitivity sweeps on grid voltage and frequency were completed in order to determine optimal choices for both parameters. Results indicate that microgrid performance metrics are optimized for ECO-150 near 6 kilovolts (kV) and 1 kilohertz (kHz), with the dc and hybrid grids having a greater sensitivity to voltage than the ac grid. Advantages of the dc and hybrid grids include ability to provide powered yaw, and ability to incorporate energy storage. However, powered yaw control was investigated and determined to be less effective than a conventional tail on a per mass basis. After accounting for the mass of the associated thermal management system (TMS), the dc grid emerges as the lowest mass option above 3 kV, followed by the ac and the hybrid grid. However, ac grid achieves a transmission efficiency 2–3% higher than the dc grid, which will have system level effects on fuel burn, fuel weight, and overall propulsive efficiency. For near term practical implementation of turbo-electric distributed propulsion, the ac synchronous system should be considered seriously as a strong candidate.

ROSAS Wind Tunnel Test Campaign Dedicated to Unconventional Aircraft Concepts Study

Abstract: An extensive acoustic wind tunnel test campaign was conducted between March and September 2003 in the frame of the European research project ROSAS to assess experimentally the noise shielding effectiveness of classic airframe components for unconventional aircraft configurations for the first time ever in Europe. A complete aircraft model (1/11th-scale) was installed in the ONERA CEPrA19 anechoic wind tunnel, successively with a fan and a jet noise simulator representing the noise sources of an advanced, high bypass ratio turbofan. Various positions of the engine with respect to the airframe were tested with noise measurements being performed in the far field. The ROSAS test campaign has allowed gathering a comprehensive database on noise installation effects for novel aircraft concepts, yet with the shortcomings of the first of its kind. Hence the effects of the noise source characteristics, of a number of geometrical parameters and of the external flow were analyzed to some extent. Significant noise attenuation was evidenced as expected, and other secondary installation effects were also studied. This paper presents the ROSAS experiment, results and preliminary analyses of the acoustic shielding phenomena.

Liquid level monitor having a plurality of proximity sensors and a sensor actuating element

Abstract: Signal generating apparatus comprises a linear series of Hall-effect switches (44) arranged as a plurality of linear arrays in discrete probes (46a, 46b . . . 46n) which are butted end to end. Each switch is closed when in proximity of an actuating magnet (40) moveable along the series of switches. In each array a resistance chain (66) is linked at intervals to the switches. Movement of the magnet along an array thereby gives a progressively changing voltage on an output line (50) from the resistance chain as a cumulative signal indicating the position of the magnet. When the magnet moves from one array to the succeeding array after generating a maximum cumulative signal from said one array, that signal is maintained by a latch connection (56) between the two arrays. A cumulative signal representing the magnet position relative to the complete series of switches can thus be generated. The arrays are powered in parallel so that it is possible to extend substantially the total number of switches or indicating points in the apparatus.