الفهرس 
Chapter 1Only 14 pages are availabe for public view
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Abstract
Journal bearings are definitely among the most important components in ship shafting propulsion systems related to ships and marine fields. To get good propeller characteristics (e.g. high efficiency), marine shafts usually work at slow speeds. Such situation may have a negative effect on the behaviour of journal bearing. Hence, a very urgent need has arisen to construct a valid test rig and a CFD model to contain both the potential experimental trials in parallel to theoretical ones. The first task has been launched in the master thesis and has involved the initial design and construction of a valid journal bearing test rig. The present research is focused on developing and modifying the test rig, aiming at extending its ability to contain even wider ranges of experiments and trials. The modification has involved adding a hydraulic loading system and full monitoring processes utilizing SCADA system. Conducting versatile experiments, trials and measurements would result in inevitable errors, or rather more accurately uncertainties. Consequently, uncertainty analyses have been carried out regarding Universal Journal Bearing Test Rig (UJBTR) and the results were found out to be quite satisfactory.
The experimental results can be utilized in the development and validation of numerical model regarding hydrodynamic journal bearings. A new Computational Fluid Dynamic (CFD) model has been built using the well-known CFD package Ansys ver. 18.1, so that future experimental investigations could be coupled with computerized trials. The CFD model results were compared to the experimental outcomes and an acceptable deviation ranges were found indicating certified validity. After that, the research was focused on investigating the oil film pressure and temperature distribution within the circumferential groove bearing experimentally and numerically. Such investigations have comprised various speeds but under a constant load. They have also involved trials at a constant speed but under different loads. The CFD model has further been utilized for investigating the impacts of changing the oil viscosity grade in relation to the performance of groove journal bearing. Based on all the derived experimental and numerical outcomes, significant enhancements could be worked on and realized concerning the journal bearing performance and efficiency.