The shipping of traditional vessels that are currently used in our country is more than 6,000. Traditional vessels are built more on experience and, unlike modern commercial vessels, are not based on advanced engineering calculations, complicated computer modeling, and laboratory tests. Therefore, optimizing and reducing their fuel consumption is important, and if it is possible to increase the efficiency of the propulsion system of this type of vessels, this will be a big step towards increasing the efficiency of traditional vessels.
Special geometric sections called ducts, which are installed on the stern of commercial vessels to improve the performance of the thrust system and increase the efficiency of the propeller, have evolved significantly today. The thrust force produced by the propeller depends on the thrust efficiency. In order to improve the efficiency of the thrust system, by using these geometric sections (Ducts), many researches have been done in this field since the middle of the twentieth century. Ducts, in addition to making the wake in stern of the ship more uniform and directing the flow more uniformly towards the propeller, which improves the propeller performance, also affect the flow separation in the stern area and reduce the separation rate, which This reduces the pressure drag.
In this thesis, in addition to a detailed review of the work done in this field and also a review of the basic principles of operation of this type of equipment, especially ducts, according to the experimental hull form of traditional vessels, has been tried to install ducts around the propeller to improve the thrust efficiency of these vessels as much as possible. Also, in this research using CFD method, the performance of the duct on resistance has been investigated and its positive effect in order to increase the propeller efficiency has been observed.