Abstract
A series of model self-propulsion tests are designed by orthogonal optimization method in order to discuss the propulsive performance of a four-propeller model. The research on propulsive performance includes propulsive efficiency, axial thrust and shaft torque. Axial thrust and shaft torque are got from self-propulsion experiments, and propulsive efficiency of every propeller is calculated based on five parameters measured in self-propulsion tests and resistance tests, respectively. After testing and calculating, the percentages of propulsive performance are obtained to analyze four-propeller arrangement. Five factors with different levels are confirmed in the orthogonal experimental design. By changing transverse positions and longitudinal positions with three levels and rotation directions of four propellers with two levels, propulsive performance of each propeller would change obviously. Three ways are performed to analyze experimental results and discuss the influencing factors. The optimum combination of five factors with different levels is obtained by analyzing the effect of four-propeller arrangement. And the major factor is found according to the order of magnitude of five factors. Depending on all analyses, the optimum arrangement of propeller positions and rotation directions is acquired to distribute four propellers in the wake of the model hull.