Propulsion

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

Study of braking energy recovery impact on cost-efficiency and environmental safety of vehicle

Abstract: The article addresses the evaluation of the impact of regenerative braking on fuel consumption and, consequently, on pollutant emissions from vehicles operated under conditions leading to frequent acceleration and deceleration. We assume that the vehicle is equipped with a system of conversion and accumulation of electric energy obtained only from braking. Basic analyzed characteristics are determined by a comparison of gasoline engine operation modes with braking energy recovery and without it. As initial physicomathematical tools, we use relationships of propulsion power and energy analysis and propulsion drive operation, which were previously suggested by one of the authors. As an example of using the mentioned relationships, the article presents the analysis results for a vehicle moving in the low-speed segment of the WLTC driving cycle. Energy passing through the battery and energy reserve in it are calculated. It is assumed that the accumulated braking energy makes it possible to start moving at the next segment not using the gasoline engine; the engine starts its operation only after the energy in the battery is exhausted. Superposition of the curves of gasoline engine operation modes with and without recovery allows us to estimate changes in the energy generated. In order to account for different values of specific fuel consumption, the authors use an adjustment factor, which takes into account pollutant emissions from the vehicle depending on the average speed. Functions of changes in fuel consumption and pollutant emissions when using regenerative braking are obtained by the integration of values. The authors compare the obtained results with the results of road tests of vehicles with the energy recovery system. The materials suggested expand our knowledge of the operational properties of vehicles with electromechanical and electrical power units

Gas Turbine Propulsion Systems

Abstract: Gas Turbine Propulsion Systems in Aerospace & Defense pulls together all of the systems and subsystems associated with gas turbine engines in aircraft and marine warship applications. The subject of engine (fuel) control has undergone major changes in the past 20 years due to the advent of the digital electronic control technology and therefore existing books on the subject are typically out of date with current methods. Gas Turbine Propulsion Systems in Aerospace & Defense discusses the latest technologies in this area; including marine propulsion which is an emerging application area for the technology that involves some interesting modifications to aviation technologies. This book also fits well into the systems engineering focus of the Aerospace Series.Includes chapters on aircraft engine systems functional overview, marine propulsion systems, fuel control and power management systems, engine lubrication and scavenging systems, nacelle and ancillary systems, engine certification, unique engine systems and future developments in gas turbine propulsion systemsIncludes case studies of specific enginesIncludes applications within marine defenceAccompanied by a book companion website featuring full colour images

Influence of propeller configuration on propulsion system efficiency of multi-rotor Unmanned Aerial Vehicles

Abstract: Multi-rotor Unmanned Aerial Vehicles make use of multiple propellers, mounted on arms, to produce the required lift. This article investigates the influence on propulsion system efficiency in hover due to the configuration of these propellers. Influence of pusher or puller configuration of the propeller, number of blades, shape and dimensions of the arm, coaxial and overlapping propellers, is presented. A dedicated test bench that allows testing of various experimental setups is designed and built in order to realistically represent multi-rotor arms. Test results show that a two-bladed pusher configuration is most efficient and slenderness of the arm has more influence on efficiency than shape. A coaxial propulsion system approaches the efficiency of a single-prop system at high disk loadings. Finally, interference effects due to overlapping propellers are discussed.

Trifan powered VSTOL aircraft

Abstract: A vertical or short takeoff and landing aircraft (VSTOL) employing three high bypass turbotip fans disposed in the fuselage and faired into the upper surfaces of the wings, and driven by two gas generators to produce vertical lift and transition to cruise flight such that the tripod arrangement for the turbotip fans generates stable powered flight. In the foregoing aircraft the gas generator - turbotip fan is an integrated propulsion system having thrust vectoring devices and gas flow control valved ducts between the two gas generators and the three turbotip fans to provide all lift, control transition and cruise functions, and in which the gas flow system produces variations in bypass ratios for the various modes of operation. Furthermore, in the foregoing aircraft the lift/cruise nacelles are positioned over the wing and blended into the upper wing surface and the adjacent fuselage to achieve high induced lift through supercirculation over the wing to produce stable flight and reduce sensitivity to gust conditions at low air speeds.

On the Conceptual Design and Performance of a Matrix Converter for Marine Electric Propulsion

Abstract: Marine electric propulsion systems in ships commonly use power electronic converters to drive variable-speed electrical propulsion motors connected to propellers. Several types of power electronic converter are used, each having advantages and disadvantages, so choice becomes a compromise between steady-state and dynamic performance, efficiency, volume and weight, redundancy, and cost. This paper considers a power electronic converter topology known as the matrix converter, evaluating its design and potential operating performance in a marine electric propulsion system, thereby allowing comparisons to be made against other power converter types to establish whether the matrix converter topology has the potential to offer improved operational performance to make investment in its development as a marine propulsion converter worthwhile.