THE DEVELOPMENT OF COMPUTER PROGRAMME TO CALCULATE THE HYDRODYNAMIC LUBRICATION PERFORMANCE OF A SHIP JOURNAL BEARING

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.