Technology
Wednesday 10th November 2010, 1600hrs–1730hrs
Chaired by Patricia Woody Modern Hybrid Propulsion Solutions and HTS (High Temperature Superconducting) Propulsion Technology Dipl.-Ing. Kay Tigges, Siemens AG, Germany When it comes to propulsion systems, hybrid solutions for navy surface vessels are now highly sought after, as evidenced by the trend of navy expenditure moving towards hybrid systems with electric propulsion motors. The paper will evaluate the significant savings in running and the increased flexibility in vessel design that these technology solutions create. It will show the options available and how the optimum solution is defined and selected. The propulsion solutions available today cover a wide performance spectrum and display considerable flexibility. In the past the prevailing mixed propulsion solutions usually consisted of diesel engines and a gas turbine (e.g. CODAG = Combined Diesel and Gas turbine). Today some navies are replacing their conventional diesel engines with electrical propulsion motors, while others are moving towards full electric propulsion. So what of tomorrows’ technology? With the emergence of HTS (High Temperature Superconducting) motor technologies and the migration of vehicle hybrid electrical technologies into the marine market the opportunity to benefit from these propulsion solutions is becoming realistic for a broader range of vessel designs, where today space limitations are restricting the opportunity. Up to now most of the efforts for developing HTS technology have been directed to devices for grid applications. However, HTS synchronous machines as motors and generators are becoming increasingly interesting within world-wide development programs. Since 1999, Siemens has been developing a future class of externally excited synchronous machines utilizing the benefits of high temperature superconductivity (HTS). Basic Principles For Ships Performance Ranking Merit Dr. Luigi Iannone, I.N.S.E.A.N., Italy Data of hydrodynamic performance of ships can be organized and presented either for making as easy as possible geometrically similar prototypes prediction calculations or for selecting the best hull form from a family or systematic series of hull forms. In this latter case, data must be organised so as to put at disposal of ship designers some so-called hull forms worthiness or merit ranking lists – or, more shortly, hull forms merit rankings – which allow to compare performance variations against geometrical parameters variations of a systematic series hull forms. In this paper, basic concepts of similitude laws and dimensional analysis will be recalled as a short but appropriate premise. Referred to the specific case of ship model testing, dimensionless parameters relative to several reference quantities – like hull length, submerged volume, wetted surface – of the physical quantity under comparison – like frictional, residual and total resistance – are also defined and illustrated in this premise. Naturally then, we will discuss the importance and significance of classifying ships power performance parameters according to simple order lists or according to much more useful merit lists: these latter ones confer the series hull forms with the meaning of behavior worthiness as the quantity under comparison concerns. These merit lists generally assume the form of an abacus comprising a set of curves – one for each hull form of the family – of the ordinate dimensionless parameter relative to the quantity under comparison against the abscissa dimensionless parameter satisfying the similitude law. Rarely is it possible to construct rigorous merit lists completely fulfilling the appropriate similitude law, in which the ordinate parameter is made dimensionless through all the quantities included in the abscissa dimensionless parameter. In some practical cases, it΄s required to know which is the family hull form having a given quantity with the minimum value of the quantity under comparison, like for instance the surface with the minimum total resistance. In such cases, approximate merit lists must be constructed, in which the ordinate parameter is made dimensionless through all the quantities included in the abscissa dimensionless parameter, only the above given quantity excluded.
In many other cases it΄s usual – as in the Anglo-Saxon literature – and very useful to construct virtual merit lists only virtually fulfilling the appropriate similitude law, in that all hull forms of the family are reported to a same given quantity, like volume of 1.000 m3 or length L = 400 ft: in such a case the similitude law and then the merit list hold only for the hull forms as reported in geometrical similitude to the assumed reference quantity. Of course, in this case too, virtual merit lists can be either rigorous or approximate. In summary, full details are given for constructing, interpreting and utilizing all possible merit lists, in conjunction with many examples of practical cases, for every hydrodynamic kind of hull forms, i.e. for both surface ships and submerged submarines. At last, but not at least, a noticeable property is also illustrated and appropriately pointed out, that allows to show up much more significant trends in the merit lists curves. Marine Machinery Health Monitoring and Prognostics - Opportunities and Challenges from the U.S. Navy Perspective Mr. Michael Dipilla, Naval Sea Systems Command (Philadelphia), United States Condition Based Maintenance (CBM) has been official U.S. Navy policy since 1998 and traces its roots back much earlier, to the late 1970's. Over the course of time, the ability to prognosticate 'remaining useful life' or RUL has been the brass ring of CBM. This capability, to large degree, has remained elusive as a wide-spread capability, yet remains a goal pursued by many organizations, including the USN. This paper will provide a survey of current efforts, successes and challenges in attaining the higher level of CBM enabled by prognostics. Topics addressed will include: data availability / quality, modeling, validation & verification, and selected case studies. The US Navy's Life Cycle Managers for Condition Based Maintenance Systems program office along with industry partners, will present their goals, real-world experiences and assessment of the current 'state-of-the-art'. Soft Kill – The Key to Affordable Defence of Ships Mr. Richard Lord, Chemring Countermeasures Ltd., United Kingdom This presentation will provide an overview of the major advances underway in improving soft kill capability through a combination of significantly improved launchers and effectors. How to defeat the most challenging targets will be the theme drawing the trends in changes to the threat which occur as a result of the roles Government’s expect the Navy to deliver.
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