The Preliminary Study Of Design Method Of Multi-Propeller Propulsion

The design method of multi-propeller propulsion is proposed in this thesis by the study of interaction factor. Interaction factor of multi propellers of conventional distribution is determined by the method of self-propelled test. The interaction factor of multi propellers is applied to triple-propeller craft, four-propeller boat and aircraft carriers. Besides, interaction factor of duct is also proposed to design ducted tandem propeller.The framework of this paper is as follow:Firstly, the author introduces the development of high-speed marine vehicles, presents the propulsion characteristics of multi-propeller vessels, and gives the focus of this paper.Secondly, interaction factor is proposed to design the propeller of multi-propeller vessels. An experimental method is suggested to determine the interaction factor of multi-propeller propulsion, and quantitative analysis of influence factor is also performed according to a series of model testing of a four-propeller craft. The optimum distribution of four propellers is discussed based on different response variables and the significant factor is also confirmed by unbalanced analysis of variance.Thirdly, the interaction factor is applied to propeller design and analysis of multi-propeller vessels. The difference in propeller design between considering and not considering interaction factor is compared based on a triple-propeller crew boat. Propeller cutting of considering interaction factor for a four-propeller craft is also discussed to improve the engine performance.Fourthly, the interaction factor is applied to propeller design of aircraft carriers. Two different longitudinal distributions are discussed for the propeller design of Kuznetsov class aircraft carriers. Meantime, empirical formulas relating the speed and power to principal dimensions of aircraft carriers have also been obtained through regression analysis of available data of106aircraft carriers. The goodness of fit of these formulas is finally analyzed through statistical tests.Chapter5gives a method to design ducted tandem propeller according to the open-water charts of ducted propeller and design theory of tandem propeller. The design procedure of ducted tandem propeller is introduced by an amphibious vehicle, and the propulsive performance of ducted tandem propeller is compared with ducted propeller for the same amphibious vehicle.