MODELLING SCREW PROPELLER CHARACTERISTICS FOR OPTIMAL PERFORMANCE
MODELLING SCREW PROPELLER CHARACTERISTICS FOR OPTIMAL PERFORMANCE
Abstract
For the screw propeller to operate optimally there is the need to model the propeller characteristics using its hydrodynamic parameters. This work entails the use of MATLAB to model the performance characteristics of the propeller taking into consideration the propeller design equations with reference to the methodical series. The performance analysis was done with a four (4) bladed propeller with varying blade area ratio (expanded area ratio) of 0.4, 0.55, 0.70, 0.85 and 1.00. The performance (including cavitation criteria effects) of the largest possible optimal diameter was evaluated. The results show reasonable values of diameter for all the BAR’s except for expanded area ratio of 0.4 where a value of 8.75m larger than the draft was obtained and thus unacceptable. A table of propeller hydrodynamic values (diameter, open water efficiency, area and area ratios, advance coefficient) was obtained after two or more design iterations during the modeling process. A noticeable variation was observed to exist between the parameters, particularly with the diameter which was chosen as the core modeling parameter for establishing the optimal performance condition of the propeller. The results of the analysis reveal that a total ship resistance of 816.9612kN and an effective power of 8398.4434kW are expected for a vessel speed of 20knots during operation.
Keywords
Efficiency; Propeller Blade Area Ratios; Speed, Effective Power; Ship Resistance;
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