Thesis

A systematic methodology enabling marine engine health assessment by employing first-principles digital twins

Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2023
Thesis identifier
  • T16572
Person Identifier (Local)
  • 201952386
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • The maritime industry faces significant challenges due to its dependence on the global economy, stringent regulations, and harsh operating environment of ships. Inevitably, motivated by the advent of digitalisation, the ship’s engines play a prominent role in addressing such challenges, considering that they are the largest energy consumer on board. Therefore, this drives the need for a systematic methodology incorporating digital twins, to enable the health assessment of marine engines. This is achieved via a five stage systematic methodology, in which the first stage involves the setup and formulation of a thermodynamics model. In the second stage, this model is utilised in a rigorous calibration process along with minimal shop test data to develop the healthy conditions digital twin. In the third stage a novel approach considers an inverse crankshaft dynamics model to reconstruct the in-cylinder pressure curves employing Instantaneous Crankshaft Torque (ICT) measurements. In the fourth stage the inverse crankshaft dynamics model is employed in tandem with the thermodynamics model to configure the current engine conditions digital twin. In the fifth and final stage, the healthy and current conditions digital twins are utilised to benchmark the engine performance and assess the engine health. The healthy conditions digital twin provides results of sufficient accuracy with less than 3% maximum error in the BSFC and peak in-cylinder pressure, considering a 4-stroke W9L46C and 2-stroke 6RTflex50 engines. Furthermore, the inverse crankshaft dynamics model reconstructs the in-cylinder pressures with errors just exceeding 5% for the W9L46C engine. Finally, the health assessment reveals a 2.1% average increase in BSFC, as well as 6.1% increase and 6.8% reduction in Exhaust Gas Temperatures (EGTs) and Indicated Mean E↵ective Pressures (IMEP) respectively, for the under-performing cylinders of the W9L46C engine. The systematic methodology proposed successfully develops both healthy and current engine conditions digital twins, making novel use of ICT measurements as well as first-principles models for any engine type (4-stroke, 2-stroke) and configuration. Therefore a systematic approach which leads to quantified benchmarking is established, enabling effective health assessment of marine engines.
Advisor / supervisor
  • Theotokatos, Gerasimos
Resource Type
DOI

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