Efficiency Improvement of a Natural Gas Marine Engine Using a Hybrid Turbocharger

The use of a computer simulator, previously developed and validated, applied to a four-stroke marine dual-fuel engine, has allowed the authors to present in this paper a solution to improve the overall efficiency of the engine by adopting a hybrid turbocharger. This component replaces the original one allowing, in addition to maintaining the previous usual functions, the production of electricity to satisfy part of the ship's electric load. In this study the application of the hybrid turbocharger concerns an engine powered by natural gas in particular. The turbocharger substitution involves a significant variation of the engine load governor operating mode. The improved engine characteristics that the hybrid turbocharger facilitates, compared to the original, are highlighted by the results reported in tabular and graphical form, for different engine loads and speed

Systems modeling for electric ship design

Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004.Leaf 185 blank.Includes bibliographical references (leaves 172-174).Diesel and gas turbine electric ship propulsion are of current interest for several types of vessels that are important for commercial shipping and for the next generation of war ships. During the design process of a platform, a choice has to be made between two different fundamental concepts regarding propulsion; a conventional arrangement, and a diesel or gas turbine electric propulsion. For both concepts, the electrical installation is present and the demand for additional electric energy becomes a dominant parameter. In both cases, the selection of the prime mover significantly influences the effectiveness of the design. In this thesis, the simulation modeling of a complete propulsion system will be attempted, with overall emphasis on the prime movers. In the first part a diesel engine is considered. The time delay between changing a set point for the revolutions of the engine and the change of the real revolutions is often modeled as a first order system. However, this modeling is too simple to describe the real behavior of the diesel engine. More complex models exist, but in general they are too complex, describing the full thermodynamic behavior of diesels.(cont.) So there is a need for a model that is more advanced than a first order system and less complex than complete thermodynamic models. Such a model has been derived, based on the Seiliger (thermodynamic) process. The results of the model show that the diesel engine behaves like a second order system when operating in the governor area and more like a first order system in the constant torque (overload) area. The simulation model of a diesel engine can be regarded as an explanation of the real engine operation, which combines the mathematical relationship between the relative components and can be used to simulate dynamic loading of the diesel engine. In the second part, a development of a nonlinear gas turbine model for loop- shaping control purposes is presented. The nonlinear dynamic equations of the gas turbine are based on first engineering principles. In order to complete the model, constitutive algebraic equations are also needed. These equations describe the static behavior of the gas turbine at various operating points.(cont.) The complete, substituted nonlinear model is presented along with its model verification results based on a simulator and measured data. A mathematical description for the electric part of the propulsion and energy generation system with respect to numbers of components such as generators and thruster drives is attempted. Other electrical loads may be represented with an aggregate load. Based on the control functions focus on power production, advanced dynamic models shall be used for the generators and simplified static models shall be used for thruster drives and other loads. The final model shall be in a state-space vector form, suitable for control design. As a conclusion, a reliability analysis on the decision for the electric propulsion system is utilized based on market data, speed and electric energy requirements studies. The purpose of this study is to justify the employment of innovative and efficient electric propulsion systems for the future needs of the commercial and naval ship industries.y Charalambos Soultatis.Nav.E.and S.M

Proceedings of SIRM 2023 - The 15th European Conference on Rotordynamics

It was our great honor and pleasure to host the SIRM Conference after 2003 and 2011 for the third time in Darmstadt. Rotordynamics covers a huge variety of different applications and challenges which are all in the scope of this conference. The conference was opened with a keynote lecture given by Rainer Nordmann, one of the three founders of SIRM “Schwingungen in rotierenden Maschinen”. In total 53 papers passed our strict review process and were presented. This impressively shows that rotordynamics is relevant as ever. These contributions cover a very wide spectrum of session topics: fluid bearings and seals; air foil bearings; magnetic bearings; rotor blade interaction; rotor fluid interactions; unbalance and balancing; vibrations in turbomachines; vibration control; instability; electrical machines; monitoring, identification and diagnosis; advanced numerical tools and nonlinearities as well as general rotordynamics. The international character of the conference has been significantly enhanced by the Scientific Board since the 14th SIRM resulting on one hand in an expanded Scientific Committee which meanwhile consists of 31 members from 13 different European countries and on the other hand in the new name “European Conference on Rotordynamics”. This new international profile has also been emphasized by participants of the 15th SIRM coming from 17 different countries out of three continents. We experienced a vital discussion and dialogue between industry and academia at the conference where roughly one third of the papers were presented by industry and two thirds by academia being an excellent basis to follow a bidirectional transfer what we call xchange at Technical University of Darmstadt. At this point we also want to give our special thanks to the eleven industry sponsors for their great support of the conference. On behalf of the Darmstadt Local Committee I welcome you to read the papers of the 15th SIRM giving you further insight into the topics and presentations

Optimisation model for a ship's hybrid energy system with a Flettner rotor

This thesis attempts to investigate the effect of the implementation of Flettner rotors in the topology of the cruise ship Silja Serenade, which, in the year of this thesis dissertation, travels from Helsinki to Stockholm. The aim is the implementation of simulation models written in Matlab that simulate the behaviour of the ship topologies’ components, with the goal of minimising the global fuel consumption. The models refer to a particular time period defined by the provided data, but the structure is completely general and can be applied to the most different data and time periods, and for every ship. The topologies will consider the presence of a battery and a shaft generator. In the first part of this work, the literature part is described, covering the reasons of fuel consumption’s restrictions, the Flettner rotor’s old and recent history, the fundamentals of the ships’ topologies and a brief introduction to the optimisation theory. Those chapters are essential in order to comprehend what are the motivations for the research topic and how the work is developed. The second part includes the building of the optimisation models, the logic that they follow and the results. Each component of the topologies is explained separately, clarifying the assumptions taken over them and explaining why they are reasonable. The optimisation models are explained step by step, discussing why each decision is taken and how they influence the final results. In the final part, final conclusions are drawn. Results compare the case of different topologies in order to establish firmly the impact of the various topologies arrangements on the total fuel consumption, with a special focus on the effects that the Flettner rotors’ implementation has on it

Annual General Assembly of the International Association of Maritime Universities

978-84-947311-7-

30th International Conference on Condition Monitoring and Diagnostic Engineering Management (COMADEM 2017)

Proceedings of COMADEM 201

Logic-based optimal control for shipboard power system management

The capability to dynamically reconfigure future naval integrated electric power systems is central to the Navy’s vision of the future combat ship. The objective in this thesis is to design, implement and evaluate a Shipboard Power System Management system that will prevent loss of power at critical buses when damage conditions are encountered. The approach that we are proposing is based on a new paradigm for the design of optimal control systems for hybrid systems, i.e., systems composed of continuous dynamics and discrete events. Discrete events may involve external disturbances, the discrete action of protection devices or control systems. The essence of the idea is that the discrete acting subsystems are naturally associated with a set of logical conditions or logical and the continuous system dynamics are usually described by differential equations or differential-algebraic equations. We will introduce a dynamic programming method forhybrid systems that solves dynamic optimization problems involving both binary and real variables. The stability analysis of the hybrid control systems is conducted via bifurcation control analysis. The state feedback controller strategy for the mode switching of the power system is obtained through Mixed Integer Dynamic Programming. It is computed in the form of a lookup table that represents a mapping from combinations of modes, and continuous states to the required switching actions. Simulations results will be analyzed.Ph.D., Mechanical Engineering -- Drexel University, 200

Radar Technology

In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design

Modelling and optimisation of Solid Polymer Fuel Cell (SPFC) systems for transportation and stationary applications

Research and development of solid polymer fuel cell (SPFC) systems for the transportation and stationary power generation industries has evolved rapidly over the last decade. This growth has been due to the ever-increasing demand for a cleaner and more efficient technology in these industries. To compete with the existing technology, SPFC systems have to be highly efficient at both full and partial loads, environmentally friendly (in terms of emissions and noise) and competitively priced. For many applications, SPFCs have the potential to deliver a system that can fulfil these criteria. However, a number of system design issues have to be addressed in order to provide a well-integrated and optimised system, which is a practical alternative to conventional modes of energy conversion. [Continues.