Ducted Propeller Design And Experimental Study

The shrouded-propeller has been used since 1930, because of the shroud around the propeller, the flow speed passing through the propeller is increased, then thrust produced by the propeller increased as well. The shroud itself also provided thrust, so the shrouded-propeller has more thrust and higher efficiency. In the other hand, the shroud designedproperly can decrease the noise of the propeller system. So it is used widely in ships, aircraft,and is developing all along.In the present work, there are two methods to design the shrouded-propeller. One is based on the blade element and momentum theory, the other is based on the Ufbng-line(surface) theory derived from circumfluence theory. The former is used widely because it avoids complex calculations. The later is used more widely with the developing of the CFD, and it can get more detail data and higher precise result for the propeller design.In the 1960's, the circumfluence theory has been used to design the shroud-propeller, and it can be divided to two methods, one is that the profile of die shroud is provided, the other is that the pressure distribution of the shroud is provided.. In this thesis we have get the profile of the shroud, the shroud is simulated by circle source and sink series, and the propeller is simulated by a actuating disk. The aerodynamic interference between the shroud and the propeller is calculated by lifting line theory.Its precise, proved by wind tunnel test here, satisfies the engineering demand. And the optimum design used here also gets the expected result.