Failure Mode and Effects Analysis of Equipment Based on Grey Theory

Based on the uncertaintyproblem of decision factors in the fault diagnosis and maintenance ofequipment, the fuzzy method and grey theory were introduced. Firstly, fuzzyterms were applied to describe the basic variables (probability of occurrence,severity and detection). Triangular fuzzy number was selected to carry out thequantitative calculation of fuzzy terms and the defuzzification of membershipfunctions. Then the grey correlations of all Failure modes were computed andrisks were ranked, considering the relative importance of decision factors. Thefuel system of marine diesel engine was taken as an example. It is pointed thatalthough the risk priority numbers are equal, if the values or weights ofdecision factors are different, then the risk levels of Failure modes aredifferent as well. The results indicate that the calculation model can identifythe failures of ship equipment more precisely and optimize allocation ofmaintenance resources.

Download Full-text

Risk Assessment tools for categorisation of failure modes of Marine Diesel Engine: A comparative study

Journal of Advanced Engineering and Computation ◽

10.25073/jaec.201821.80 ◽

2018 ◽

Vol 2 (1) ◽

pp. 30

Author(s):

Ikuobase Emovon ◽

Modestus Okechukwu Okwu

Keyword(s):

Risk Assessment ◽

Diesel Engine ◽

Failure Modes ◽

Assessment Tools ◽

Risk Level ◽

Marine Diesel Engine ◽

Risk Matrix ◽

Creative Commons ◽

Risk Assessment Tools ◽

Marine Diesel

Risk assessment is a vital element of most maintenance system, this is because safeguarding of equipment item requires maintenance strategies which usually depend on the degree of risk of the equipment item. In this paper two risk assessment tools; Risk Priority Number (RPN) based approach and Risk Matrix (RM) based approach, are presented for categorisation of risk of failure modes of marine diesel engine. The techniques are used to categorise failure modes into three risk levels; low, medium and high in turn and based on the risk level, maintenance strategy are assigned to each failure modes. Furthermore, the two techniques are compared and the result of the analysis revealed that, the extent of Risk matrix method similarity to the RPN approach depends on the benchmark for setting the risk level limit in the RPN method. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Download Full-text

Combustion Fault Simulation of Diesel Engine Based on AVL-FIRE Software

10.3233/atde210271 ◽

2021 ◽

Author(s):

Junfu Yuan ◽

Chunsheng Zhao

Keyword(s):

Diesel Engine ◽

Fault Simulation ◽

Complex Structure ◽

Combustion Process ◽

Calculation Model ◽

Marine Diesel Engine ◽

Marine Diesel ◽

Cause Of Failure ◽

Engine System ◽

Engine Failure

Marine diesel engine is developing towards the direction of precision, automation and systematization, and it has the characteristics of complex structure and many parts. If it breaks down, it will affect the operation safety of the whole ship. If it is serious, accidents may occur, which may cause maritime accidents. Therefore, how to prevent the occurrence of marine diesel engine failure and analyze the cause of failure after the accident has been paid more and more attention by scholars at home and abroad. In the simulation study of the working process of diesel engine, for different types of diesel engines, the laws of combustion process are different, even for the same diesel engine in different working conditions, the combustion laws are also different, which will cause great difficulties to study the combustion process. Using computer simulation technology, the physical calculation model of diesel engine system is established by simulating the typical combustion faults of marine diesel engine. AVL-FIRE software is used to simulate different faults of diesel engine combustion process, and the changes of various performance parameters of diesel engine under corresponding faults are obtained, so as to grasp its working state macroscopically, and provide relevant basis for the design, optimization and operation management of diesel engine system.

Download Full-text

Research of the radial-axial turbine of the marine diesel engine impulse turbocharging system

MORSKIE INTELLEKTUAL`NYE TEHNOLOGII ◽

10.37220/mit.2021.52.2.010 ◽

2021 ◽

pp. 74-79

Author(s):

А.В. Пассар ◽

Д.В. Тимошенко ◽

А.Н. Бердник

Keyword(s):

Diesel Engine ◽

Design Method ◽

Stationary Flow ◽

Calculation Model ◽

Marine Diesel Engine ◽

Closed Model ◽

Axial Turbine ◽

Medium Speed ◽

Effective Performance ◽

Marine Diesel

В статье представлены результаты исследований радиально-осевой турбины, работающей в составе импульсной системы наддува среднеоборотного судового дизеля. Исследования носили теоретический и экспериментальный характер и базировались на предлагаемом методе проектирования и расчета, который комбинируя на определенных этапах модели расчета радиально-осевой турбины, а также замкнутую модель рабочего процесса комбинированного двигателя, позволяет решать задачи проектирования проточных частей турбины для работы в нестационарном потоке импульсной системы наддува. Целью исследований является отработка основных положений предлагаемого метода проектирования радиально-осевой турбины, работающей в составе импульсной системы наддува комбинированного двигателя, на примере поиска оптимальных параметров радиально-осевой турбины турбокомпрессора среднеоборотного судового дизеля размерности 18/22. В работе получена модернизированная геометрия проточной части турбины. Представлены результаты экспериментальных и расчетных исследований характеристик модернизированной и штатной турбин, подтверждающие повышение эффективности модернизированной турбины во всем диапазоне ее характеристики. Представлены результаты испытаний судового дизеля 6ЧН 18/22 с модернизированной и штатной турбинами по нагрузочной характеристике, показывающие положительное влияние измененной геометрии турбины на эффективные показатели дизеля и подтверждающие возможность использования предлагаемого метода проектирования радиально-осевой турбины системы наддува комбинированного двигателя. The article presents the results of research on a radial-axial turbine operating as part of a pulsed boost system for a medium-speed marine diesel engine. The research was theoretical and experimental in nature and was based on the proposed design and calculation method, which combines at certain stages of the radial-axial turbine calculation model, as well as a closed model of the combined engine workflow, allows you to solve the problems of designing the flow parts of the turbine for operation in a non-stationary flow of a pulse boost system. The aim of the research is to develop basic provisions of the proposed design method of the radial-axial turbine, which is part of pulse systems boost engine combined, for example, finding the optimal parameters of the radial-axial turbine of the turbocharger, the medium-speed marine diesel dimensions 18/22. The upgraded geometry of the flow part of the turbine is obtained. The results of experimental and computational studies of the characteristics of upgraded and standard turbines are presented, confirming the increase in the efficiency of the upgraded turbine over the entire range of its characteristics. The results of tests of the 6ChN 18/22 marine diesel engine with upgraded and standard turbines on load characteristics are presented, showing the positive effect of the changed turbine geometry on the effective performance of the diesel engine and confirming the possibility of using the proposed method of designing a radial-axial turbine of the combined engine supercharging system.

Download Full-text