INTEGRATION OF MODERN MACHINERY SYSTEMS

Abstract

AbstractWith the advent of gas turbine prime movers for both propulsion and electric power generation, new methods of optimizing thermal efficiency are needed if weight and cost limits are to be achieved by new ship designs without sacrificing operational capability. The balance of primary power generation from fuel and secondary power generation utilizing other energy media must be reviewed. Where once the basic shipboard energy conversion was Bunker C fuel into steam within a large boiler, using steam as the energy medium for all power and heating use, we now have machinery systems that convert fuel into energy at several subsystem levels, i.e. propulsion, electric power, auxiliary steam and so forth. The design challenge for today's machinery system engineer is to optimize thermal recovery from fuel much the same as economizers, etc. that were used in previous steam plant designs. This can be done by making one system dependent upon another for its source of energy. However the design constraint demanded by NAVY combatant ships is that operational flexibility, vulnerability protection and reliability/maintainability/availability goals for each dependent system must be maintained should the primary energy source system fail.This paper presents an engineering approach to generating and evaluating alternative machinery designs within the structure of a set of ship design criteria categories. These categories are defined and examples of machinery system design objectives given. A design process is then proposed which includes determination of energy requirements, identification of alternate energy generation/conversion hardware and verification of adequate energy supply under all operating modes. Discussion is given to the importance of selecting the proper energy medium (fuel, electricity, steam, etc.) for each functional service if energy generation and energy absorption are to be efficiently matched. An evaluation approach is then presented which compares total performance of candidate designs on a system‐level basis.Finally, the paper describes two recent ship designs where integration of machinery systems has taken place: the Canadian DDH‐280 Class Destroyer and the U.S. Navy DD‐963 Class Destroyer. Elements in the “trade‐off” studies for these ships are reviewed and design advantages discussed.