Technical Condition Indexes for Ship Engine Auxiliary Systems

• Main Author: Eriksen, Christofer Magnus
• Format: Others
• Language: English
• Published: Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk 2010
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11470

The topic of my individual Master Thesis study is the expansion of the Technical Condition Index (TCI) concept, developed at the Department of Marine Technology at NTNU, as to encompass the following Ship Engine Auxiliary Systems; Fuel Oil System, Lubricating Oil System and Cooling Water System. The first chapter is a literature study on condition monitoring techniques, including an introduction on the role of TCI’s and condition monitoring within a successful maintenance organization. FMECA analysis concluded during the candidate’s Specialization Project revealed three major common component groups subject to condition monitoring for the purpose of establishing TCI’; valves, pumps and heat exchangers. In order to reduce complexity and cost implications, TCI’s and the condition monitoring techniques providing input data should be based on standardized methods, applicable to all components within one such major group. For valves in the systems studied such standardized methods generally applicable to all valves could not be identified. The variety of valve types is vast, while common root-cause failure mechanisms are few, indicating that if valves truly are considered sufficiently critical to justify condition monitoring based on TCI’s, methods must be developed individually each system to be monitored. For pumps, TCI’s are proposed to be based on a combination of vibration monitoring and process parameter analysis. Vibration monitoring should be based on measurement of vibration velocity, given in mm/s-RMS at bearings. ISO standards classification threshold values are proposed utilized in the transfer functions for calculating TCI’s. TCI’s based on process parameter analysis of pumps should utilize the Head – flow test at duty point. This method requires repeatable measurements flow rate and pressure difference over the pump. TCI’s for heat exchangers are proposed to be based exclusively on process parameter analysis, where the parameter to be monitored is the reduction in the overall heat transfer coefficient. The heat transfer coefficient is calculated from measurement of inlet and outlet temperature of both mediums flowing through the heat exchanger as well as mass flow rate and knowledge of the specific heat capacity of at least one of the two mediums. Technical Condition Indexes proposed have been implemented into TeCoMan software for the Engine Fuel Oil System, and exemplified by calculation of aggregated higher level TCI’s using fabricated data. Detailed description of the TeCoMan software and how to efficiently include a planned condition monitoring programme to calculate TCI’s is included.