Topic
Propulsion
About: Propulsion is a research topic. Over the lifetime, 24977 publications have been published within this topic receiving 200311 citations.
Papers published on a yearly basis
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TL;DR: In this paper, an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations is presented. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3-D unsteady, full wheel CRP CFD computations and aero-acoustic simulations.
Abstract: Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3-D unsteady, full wheel CRP CFD computations and aero-acoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full wheel unsteady 3-D RANS simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method were extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in the literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was re-designed for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the re-designed CRP demonstrated an average reduction of 7.25 dB in mean SPL computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the re-designed CRP demonstrated a reduction of 9.2 EPNdB and 8.6 EPNdB at the FAR 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.Copyright © 2010 by ASME
41 citations
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25 May 2020TL;DR: In this paper, a multiphase permanent magnet synchronous motor (PMSM) for the more electric aircraft propulsion is presented, where the stator winding of the motor is composed of multiple sets of multi-phase windings with different parameters.
Abstract: This article presents a multiphase permanent magnet synchronous motor (PMSM) for the more electric aircraft propulsion. The stator winding of the motor is composed of multiple sets of multiphase windings with different parameters. The purpose of the motor design is to modify the distribution of the high-efficiency area of the motor by reasonably matching the winding parameters of each set, thereby making the motor more suitable for the working condition of more electric aircraft and improving the working efficiency of the motor. This article analyzes the selection principle of slot–pole combination and the influence that asymmetric windings have on the motor magnetic field. Three basic matching modes are proposed: equal torque matching, equal power matching, and equal speed matching. The motor model is established, with the external characteristics, efficiency, and dynamic response of different matching modes being compared and analyzed. The results show that equal torque matching and equal speed matching can reduce the total loss of the motor in a complete flight working condition, whereas equal power matching is not suitable for more electric aircraft.
41 citations
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23 Dec 1993TL;DR: In this article, a hybrid-drive vehicle equipped with a main IC engine and a battery-powered electric machine and including separate clutch couplings is described, where an electrical auxiliary can be engaged to power the transmission shaft and output gearbox when independently supplied from an accumulator.
Abstract: A method of controlling a hybrid-drive vehicle i.e. a vehicle equipped with a main IC engine (6) and a battery powered electric machine and including separate clutch couplings (3, 5) employs an electrical auxiliary (4) which can be engaged to power the transmission shaft (1) and output gearbox (2) when independently supplied from an accumulator (7) or to operate as a recharging generator. In this latter mode the IC engine (6) provides both vehicle propulsion and generator drive or on a downward incline regenerative braking may temporarily replace the engine (6) for accumulator (7) re-charging.The electric drive is employed for environmentally restricted low speed/low energy running e.g. in town centres followed by main engine running/recharging elsewhere.
41 citations
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17 Sep 1982TL;DR: In this article, a vehicle equipped with a propulsion control system combined with an anti-blocking system, a pressure reservoir provided as a brake pressure supply-source which can be charged by means of the return pump of the antiblocking system is described.
Abstract: In a vehicle equipped with a propulsion control system combined with an anti-blocking system, a pressure reservoir provided as a brake pressure supply-source which can be charged by means of the return pump of the anti-blocking system, whereby the charging operation is valve-controlled so that the feed from the return pump is directed into the pressure reservoir during pressure-reduction phases of the propulsion control system, the pressure reservoir can also be charged, outside the control phases of the propulsion control system, either by operating the driver's brake pedal or by automatic activation of a charging circuit accompanied by the operation of the return pump.
41 citations
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06 Oct 1996
TL;DR: A new type of contact-less wafer manipulator, featuring "direct electrostatic levitation and propulsion of silicon wafer" (DELP-SW), has been successfully developed.
Abstract: A new type of contact-less wafer manipulator, featuring "direct electrostatic levitation and propulsion of silicon wafer" (DELP-SW), has been successfully developed. The novel aspect of this manipulator is that a silicon wafer can be directly levitated and driven via electrostatic forces. In this paper, a brief review of basic principles is presented. This is followed by a description of the structure of a prototype DELP-SW mechanism, including electrode design, position feedback control method, driving principle and the operational procedure. Experimental results which demonstrate completely contact-less transportation of an 8-inch silicon wafer are also presented.
41 citations