Institution
Rolls-Royce Holdings
Company•Derby, United Kingdom•
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.
Topics: Turbine, Gas compressor, Rotor (electric), Turbine blade, Casing
Papers published on a yearly basis
Papers
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TL;DR: In this article, the characteristics of the thermal field and the resulting surface metallurgy induced in a next generation nickel-base superalloy have been studied for cutting scenarios involving different combinations of thermo-mechanical boundary conditions.
Abstract: Despite the ongoing progress in metallurgical characterisation of machined surfaces, knowledge of the thermal conditions under which they originate during the workpiece-flank interaction is still lacking. When cutting advanced superalloys, little is known about temperature evolution in the machined part volume, where workpiece material interacts with the tool flank. In this work, the characteristics of the thermal field and the resulting surface metallurgy induced in a next generation nickel-base superalloy have been studied for cutting scenarios involving different combinations of thermo-mechanical boundary conditions. Analysis of the thermal field evolution in the workpiece subsurface has allowed the heating and cooling rates induced by cutting to be revealed, allowing description of two distinct types of thermal cycle, with a Heating-Peaking-Cooling (H–P–C) and a Heating-Quasi-isothermal Deformation-Cooling (HQC) structure depending on the process aggressiveness. Subsurface thermal history has been found to relate with the severity of the cutting-induced deformation, as it combines information on thermal field magnitude and on the process rates. Furthermore, thermal balance equations have been applied to study the rate of the heat generation in the machined subsurface due to its own plastic deformation while interacting with the tool flank. This has revealed that the highest rate of heat generation induced by plastic deformation occurred in thin surface layers at the beginning of the workpiece-flank contact, which has been associated to the conditions under which white layers (WLs) are generated. Energy balance analysis has furthermore indicated the development of a less severe and less impulsive deformation process at higher subsurface depths, which has been linked to the formation mechanism of material drag (MD) layers. In this way, the thermal history of machined surfaces has been related to their resulting metallurgical integrity, allowing in-depth understanding of the physical conditions developing when cutting next-generation superalloys.
29 citations
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12 Aug 2015
TL;DR: In this article, an extension of the CAD-based parametrisation termed as NURBS-based Parametrization with Complex Constraints (NSPCC) is developed and applied to the aerodynamic shape optimisition of a one-stage high pressure turbine.
Abstract: An extension of the CAD-based parametrisation termed ‘NURBS-based parametrisation with complex constraints’, or NsPCC, is developed and applied to the aerodynamic shape optimisition of a one-stage high pressure turbine. NsPCC uses a test-point approach to impose various geometric constraints such as continuity, thickness and trailing edge radius constraint.To perform the shape optimisation using NsPCC, The surface sensitivity is first computed efficiently using a discrete adjoint solver. The displacements of the control points of the NURBS patches are used as the design variables and linked to the surface sensitivity through consistent application of Automatic Differentiation. A robust mesh deformation based on linear elasticity and further enhanced with sliding mesh capability is used to deform the mesh at each design step. Finally, the optimised rotor shape is exported as a STEP file. The method is demonstrated on a turbine stage where isentropic efficiency is improved by over 0.4% with both the inlet capacity and rotor reaction ratio deviation below the prescribed thresholds. Satisfaction of the G1 continuity, thickness and trailing radius constraints is verified.Copyright © 2015 by Rolls-Royce Deutschland Ltd & Co KG
29 citations
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TL;DR: In this paper, a coupled solution algorithm for the Navier-Stoke equations is proposed, in which the linearized momentum and continuity equations are solved simultaneously, and compared with the SIMPLEC method.
Abstract: In many popular solution algorithms for the incompressible Navier–Stoke equations the coupling between the momentum equations is neglected when the linearized momentum equations are solved to update the velocities. This is known to lead to poor convergence in highly swirling flows where coupling between the radial and tangential momentum equations is strong. Here we propose a coupled solution algorithm in which the linearized momentum and continuity equations are solved simultaneously. Comparisons between the new method and the well-known SIMPLEC method are presented.
29 citations
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15 Apr 2010TL;DR: In this paper, an aircraft has a lift/propulsion unit which includes a power unit such as a turboshaft engine which drives a fan through a transmission mechanism, which can be independently swivelled to provide lift or propulsion thrust.
Abstract: An aircraft having a lift/propulsion unit which includes a power unit such as a turboshaft engine which drives a fan through a transmission mechanism. The fan discharges to vectoring nozzles which can be independently swivelled to provide lift or propulsion thrust. An output shaft of the transmission mechanism serves as the main shaft of a motor/generator of modular form. The motor/generator can act as a generator to charge an electrical storage device such as a battery, or as a motor to drive the fan, either alone or to supplement the output of engine. Reaction control nozzles are provided at extremities of the aircraft to provide stabilizing thrust. The aircraft is capable of vertical take off and hovering, with the vectoring nozzles swivelled to a lift position, and forward thrust with the vectoring nozzles swivelled to a propulsion position.
29 citations
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TL;DR: A review of flow physics in diffusive s-shaped ducts is presented in this paper, focusing on flow control methods employed to counteract the onset of separation, swirl formation, and non-uniformity of pressure at the duct exit plane.
29 citations
Authors
Showing all 4029 results
Name | H-index | Papers | Citations |
---|---|---|---|
David A. Jackson | 136 | 1095 | 68352 |
David Harvey | 115 | 738 | 94678 |
David J. Williams | 107 | 2060 | 62440 |
Michael Walsh | 102 | 963 | 42231 |
Zi-Qiang Zhu | 89 | 1049 | 33963 |
H. K. D. H. Bhadeshia | 77 | 476 | 27588 |
Nigel P. Brandon | 71 | 412 | 18511 |
Sanjib Kumar Panda | 64 | 633 | 13808 |
Fabrizio Scarpa | 63 | 467 | 13559 |
Robert J.K. Wood | 56 | 314 | 10439 |
Howard P. Hodson | 50 | 226 | 7118 |
Martin Rose | 49 | 241 | 10299 |
Andy J. Keane | 46 | 301 | 13753 |
Stephen J. Finney | 45 | 263 | 6821 |
D.M. Vilathgamuwa | 45 | 212 | 7827 |