Performance Simulation of Marine Cycloidal Propellers: A Both Theoretical and Heuristic Approach

open4The importance of mathematical and numerical simulation in marine engineering is growing together with the complexity of the designed systems. In general, simulation a makes it possible to improve the engineering design, reducing working time and costs of production as well. In this respect, the implementation of a simulation model for cycloidal propellers is presented. Cycloidal thrusters are being increasingly used in marine applications. Their best performance concerns low-speed applications, due to their ability to steer thrust in any direction. The proposed simulator is able to assess the performance of cycloidal propellers in terms of the generated thrust and torque, without resorting to consuming and demanding computational tools, such as CFD methods. This feature makes the presented model particularly suitable for the simulation in the time domain of the maneuverability of surface units, equipped with cycloidal propellers. In this regard, after embodying the implemented model in an already existing simulation platform for maneuverability, we show the most significant outputs concerning some simulated maneuvers, performed at cruise speed.openMarco Altosole, Silvia Donnarumma, Valentina Spagnolo, Stefano VignoloAltosole, Marco; Donnarumma, Silvia; Spagnolo, Valentina; Vignolo, Stefan

Design and construction of a modular pump-jet thruster for autonomous surface vehicle operations in extremely shallow water

open5noThis paper describes a customized thruster for Autonomous Surface Vehicles (ASV). The thruster is a Pump-Jet Module (PJM), which has been expressly designed, modeled, constructed, and tested for small-/medium-sized ASVs that perform environmental monitoring in extremely shallow waters such as wetlands (rivers, lakes, swamps, marshes), where water depth is only a few centimeters. The PJM is a fully-electric propulsion unit with a 360-degree continuous steering capability. Its main advantage is that the unit is flush with the flat bottom of the vehicle. This makes the PJM suitable for operation in extremely shallow waters because the risk of damaging the thrusting unit in case of grounding is very limited. The PJM was produced using innovative materials, and the hydraulic components were all constructed using a 3D printer.openOdetti A.; Altosole M.; Bruzzone G.; Caccia M.; Viviani M.Odetti, Angelo; Altosole, M.; Bruzzone, G.; Caccia, M.; Viviani, M

Marine dual-fuel engines power smart management by hybrid turbocharging systems

The performance of a marine dual-fuel engine, equipped with an innovative hybrid turbocharger producing electric power to satisfy part of the ship’s electric load, is presented by a simulation comparison with the traditional turbocharging technology. The two distinct fuel types, combined with the hybrid turbocharger, involve a substantial change in the engine control modes, resulting in more flexible and efficient power management. Therefore, the investigation requires a numerical analysis depending on the engine load variation, in both fuelling modes, to highlight different behaviours. In detail, a dual-fuel engine simulation model is validated for a particular application in order to perform a complete comparison, reported in tabular and graphical form, between the two examined turbocharging solutions. The simulation analysis is presented in terms of the engine working data and overall energy conversion efficiency

LNG fueled barge for cold ironing: feasibility study for the emission abatement in the Port of Genoa

The scientific analysis presented in this paper aims at studying some maritime technical solutions for the electric energy generation and delivery to ships moored in port by means of LNG fueled generators installed onboard a floating unit. Two different scenarios regarding the LNG supply chain are supposed and some options for producing cleaner electric energy are then investigated. The reference area considered in this study is the old port of Genoa where the traffic of both passenger and cargo ships takes place. The paper presents an analysis concerning the main technical features of the considered solutions for an actual port calls scenario. The results regard dimensions and weights of the proposed floating units and the most significant characteristics of the generation equipment, as far as average load factor, fuel consumption and cost are concerned

Dynamic behaviour and stability of marine propulsion systems

The 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 \u2018geometric non-linear dynamics\u2019 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