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Design and Fabrication of an Optimized Wake Equalizing Duct in Order to Improve Propulsion System Operation

Ali Mirzazadeh, Siamak | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 45534 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Seif, Mohammad S; Rad, Manouchehr
  7. Abstract:
  8. Special geometrical sections, known as “duct”, which can be installed on merchant vessels stern in order to improve propulsion system and propeller performance, today have evolved considerably. The force which produces by the propeller depends on efficiency of propulsion system. In the way of improving the efficiency of propulsion systems, by using these special geometrical sections, to much research have been done from the mid-twentieth century. The Wake Equalizing Ducts (WEDs) in addition to conduct the more uniform fluid flow to the propeller disk (which causes to improve the propeller operation), affect on flow separation in ship stern zone and will decrease the separated flow zone. However, the propeller performance and separation amount decrease will lead to power saving.
    There are more than 6,000 of traditional vessels fleet (dhow) already being used in our country. The traditional vessel design is based on experience instead of advanced engineering simulations via computer. Considering this issue, the optimization and to decrease fuel consumption is an important stuff for these kinds of vessels. However, If we can improve their propulsion efficiency, In any kind, It will be a big step in the way of improving the traditional vessels performance. In this thesis, we focus on a one of the traditional vessel kinds called “Nako”.
    In the present thesis, by utilization of CFD, The operation and effect of a WED on the Nako resistance has investigated and the positive impact and the efficacy of the duct has been shown. In the next step, after fabricating the mentioned duct in the model scale (with Aluminium), its effect on propeller performance has been investigated in the cavitation tunnel of the Marine Engineering Laboratory of the Sharif University of Technology. A wakescreen has used in order to produce axial wake in the cavitation tunnel. Finally, the results have shown and analyzed in the way of energy saving for Nako traditional vessel.

  9. Keywords:
  10. Ship Propeller ; Efficiency ; Propulsion ; Wakes ; Propellers Blades ; Duct ; Dhow

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