134 research outputs found
RESISTANCE AND PROPULSION OF AN ICEBREAKING VESSEL IN ULTRA-SHALLOW WATER
No full textThis paper highlights main aspects of the shallow water effects on resistance, hull-propeller interaction and propulsive qualities of anicebreaking emergency and evacuation vessel(IBEEVs). The IBEEV is a smallsized, shallow draft vessel, owned and operated by AGIP KCO on the sea basin in the Kazakhstan sector of the Northern Caspian Sea. It was designed specifically to evacuate personnel from offshore oil installations in emergency situations taking also into account a potential hydrocarbon/toxic environment. Because of generally unsatisfactory behavior of first prototypes in full-scale operations, a comprehensive research project was planned by AGIP KCO aimed at assessing overall performanceof the IBEEV as-it-is in order to plan a possible retrofit. A number of activities sequentially involving Navalprogettiand Krylov State Research Center were implemented with the key support from the first author. These activities encompassed analytical and numerical computations, model tests in deep and shallow water. The ultra-shallow water depth showed dramatic influence on the vessel’s resistance, hull-propeller interaction, and bollard pull capability. Finally, the rope pull capability of IBEEV was assessed on the basis of resistance and self-propulsion tests
Dynamic behaviour and stability of marine propulsion systems
No full textThe paper describes an approach used to study the dynamic behaviour of marine propulsion systems. The method consists of three main steps: analytical modelling of the ship propulsion system, stability analysis of the system, and dynamic behaviour of the propulsion plant. The model is based on non-linear first-order differential equations. The concepts of ‘geometric non-linear dynamics’ are used to highlight some important properties of the model. One of the main advantages of the method is that it enables some important dynamic properties of the propulsion system to be highlighted without solving the differential equations of motion. In particular circumstances an analytical solution of the proposed model is possible; the solution includes the steady state behaviour of the system, which is useful for the engine-propulsion matching
THE INFLUENCE OF THE OPERATIONAL SCENARIOS ON THE PROPULSION SYSTEM SELECTION IN THE PRELIMINARY NAVAL SHIP DESIGN
No full textARTIFICIAL AIR CAVITY AS ENERGY SAVING TECHNOLOGY
No full textAt a time when ‘greenships’ are going to become a must according to IMO requirements and looming restrictions against pollution at sea are entering into force, energy saving solutions are recommended. Minimization of environmental impact from ships is expected as a result of applied research in different fields: hull form design and propulsion, hybrid engine technology and fuel cells. The present paper is totally devoted to the reduction of resistance and powering obtained via hydrodynamic solution. Based on the results of thelatest investigations carried out at KSRC, pros and cons of the present level of Air Cavity System (ACS) technology are discussed. Economic advantage yielded by higher propulsion
efficiency on an ACS-fitted ship is demonstrated through application on a standard container ship developed at conceptual design level.Two design solutions, that is, the ‘standard ship’ and the ‘ACS-fitted ship’, are then compared according to criteria such as powering performance, fuel consumption and shipping economics by simulating a round-voyage route
EFFECTIVE SIMPLE METHODS FOR NUMERICAL MODELLING OF MARINE ENGINES IN SHIP PROPULSION CONTROL SYSTEMS DESIGN
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Controllable pitch propeller actuating mechanism, modelling and simulation
No full textThis article focuses on the mathematical model of the pitch control mechanism for a marine controllable pitch propeller, with the aim of describing the dynamic behaviour of this kind of system and its influence on ship performance. Too great a load on the blades can result in high pressures in the actuating system, response delays and control system problems, which are ultimately responsible for most mechanism failures. The behaviour of the controllable pitch propeller actuating mechanism is considered in terms of blade position, oil pressures inside the controllable pitch propeller hub and magnitudes of the forces acting on the blades. In the proposed mathematical model, the forces acting on the propeller blade are evaluated taking into account the yaw motion of the ship, the propeller speed (including shaft accelerations and decelerations) and the turning of the blade during the pitch change. On the basis of the introduced procedure, a controllable pitch propeller numerical model as part of an overall propulsion and manoeuvrability simulator representing the dynamic behaviour of a twin-screw fast vessel is developed. The aim of this work is to represent the ship propulsion dynamics through time-domain simulation, based on which the designers can develop and test several design options, in order to avoid possible machinery overloads with their consequent failures and to obtain the best possible ship performances. In this aspect, the controllable pitch propeller model is an essential design tool
Waterjet Craft Propulsion: Study and Validation of Jet Performance Prediction Techniques
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Nuova unità di concezione multiscafo adibita al recupero degli idrocarburi sversati in mare
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