Propulsion

About: Propulsion is a research topic. Over the lifetime, 24977 publications have been published within this topic receiving 200311 citations.

Design and performance tests of cycloidal propulsion systems

Abstract: The cycloidal propeller, which can be described as a horizontal rotary wing, offers powerful thrust levels, and a unique ability to change the direction of the thrust almost instantly. In this work, cycloidal propulsion system was designed and implemented with sinusoidal low pitch system to investigate the fundamental characteristics of hovering states. Before experimental study, computational analysis was made in commercial CFD tool, CD Adopco/StarCD. This work gives schematic view of flow field around rotor. And it predicts the load variation on a blade with respect to revolution and the total thrust from cycloidal rotor, at specific condition. CFD analysis also makes it possible to check the camber effect. The propulsion system was built up with sinusoidal low pitch control mechanism. Thrust, power and efficiency were measured for various conditions of parameter setting. It was accomplished by designing the equipment which can change the rotational radius, number of blade, phase angle of eccentricity and amplitude of eccentricity.

Electromagnetic Design of Superconducting Synchronous Motors for Electric Aircraft Propulsion

Abstract: This paper evaluates the electromagnetic characteristics as to two types of superconducting motors: one is the superconducting motors adopting high-temperature superconducting field coils and copper armature windings; and the other is fully-superconducting motors, which have high-temperature superconducting field coils and MgB 2 superconducting armature windings. Analytical formulas and FEM are employed for the designs of 1.5-, 3.0-, and 5.0-MW motors. We consider how to reduce ac loss in MgB 2 winding structure as well. The analysis of our results, which was conducted mainly over output density and efficiency, suggests that the adoption of superconducting motors is more realistic in realizing electrical aircraft propulsion system in terms of higher output; the analysis results show that the fully-superconducting motors have a potential to reach over 16 kw/kg.

Improvement of drive range, acceleration and deceleration performance in an electric vehicle propulsion system

Abstract: This paper presents technologies that will be employed in a battery electric vehicle, aiming at improving the vehicle drive range, acceleration and deceleration performance and reducing the cost. Firstly it discusses a short-term power management scheme employing a high-power-density ultracapacitor bank to load level a high-energy-density, cost-effective but low-power-density Zn-Br battery for satisfactory overall performance of the vehicle power source. Then it looks at the issue of constant power operation of a BDCM propulsion system. A novel multifunctional DC-DC converter topology has been proposed for both short-term power management and the constant power operation of the BDCM propulsion system. It features simple circuitry, high efficiency, and low cost. Analysis of the operation principles of the multifunctional DC-DC converter is given. Control methods of regenerative braking of a BDCM at different operation modes are especially addressed.

Optimum interplanetary rendezvous with power-limited vehicles

Abstract: The optimum thrust programs for power-limited propulsion systems are used to generate rendezvous trajectories from Earth to Mars for various flight times and launch dates during the years 1968 to 1971. The manner in which the propulsion requirements vary with flight time and launch date is considered, and a comparison of vehicle performance using the variable and constant thrust programs is presented. The existence of optimum launch dates is interpreted in terms of certain transversality conditions derivable from the calculus of variations. A brief comparison of the advanced propulsion vehicle and the ballistic vehicle propulsion requirements is made for Earth-Mars rendezvous trajectories.

Multi-unit articulated road train propulsion system

Abstract: A distributed propulsion system is provided for a multi-unit articulated road train. The distributed propulsion system includes a tractor having a first propulsion system for propelling the tractor. A trailer is secured to the tractor at an articulated joint, such as a fifth wheel or draw bar connection. The tractor has a second propulsion system for substantially propelling the trailer. A load sensor for detecting a load between the tractor and the trailer, preferably the tensile load, is associated with the articulated joint. The load sensor produces a load signal. An input device produces a request signal for actuating the second propulsion system. An electronic control mechanism is electrically connected to the input device and the load sensor for coordinating the various sensors and inputs. The control mechanism commands the second propulsion system in response to the load signal and the request signal such that the trailer is propelled in a controlled manner relative to the tractor.