Abstract:
This study is based on the calculations of hydrodynamic lubrication
performances of a ship journal bearing. About nine (9) Raimondi and Boyd
charts were imported into MATLAB as numerical values. A computer
programme was developed by using MATLAB Graphical User Interface (GUI)
where all the codes necessary for the programming were written prior to the
analysis. The optimum clearance for the journal bearing lubrication
performances was checked by using Trumpler’s Criteria. Four analysis were
performed throughout the research where the first analysis was carried out on
the clearance of the oil-lubricated bearing. The clearances were validated with
commercial marine bearing clearance design data of Feroform and Japan
Marine Technology (JMT) for oil-lubricated bearing. The result shows a close
agreement between the clearance data. The second analysis was performed
on the water-lubricated bearing clearance and a new formula was developed
as Trumpler’s Criteria is only valid for the oil-lubricated bearing. The formula is
based on Thordon and Feroform running clearance data. The result of
comparison by applying the new formula showed a close agreement with the
commercial marine design data of Thordon and Feroform. The third analysis
was then performed by comparing the clearances for oil and water-lubricated
bearing and it shows a close agreement with Feroform bearing design data.
The last analysis was performed on the lubrication performances of the journal
bearing of different SAE oil grades and L/D ratios by using the optimum
clearances that were analyzed in the first and second analysis.
