THE AUTOMATIC DESIGN OF THE SCREW PROPELLER IN NONAXIAL FLOW

A computer program has been developed for the automatic generation of the characteristic curves of three bladed screw propellers in non-axial flow having as input the geometrical parameters of the screw propeller. The computer algorithms are based on the theoretical and experimental research on hydrodynamic characteristics of a screw propeller in non axial flow, carried out at Naval Engineering Department of Naples' University (D.I.N.) The numerical expressions of the thrust, torque, vertical force and thrust eccentricity coefficients are obtained using the ''equivalent section theory'' and introducing 'correcting'' coefficients given by the regression analysis carried out on the experimental data relative to 21 three bladed B-Wageningen screw propellers tested at D.I.N. in open water with shaft inclination of 0-degrees, 5-degrees, 1 0-degrees, 1 5-degrees, 20-degrees degrees. In this way the automatic design of three bladed propellers working in non-axial flow is developed by the knowledge of the geometrical parameters of the propeller and the inclination an le of the shaft.