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Experimental Investigation and Design of an Optimum Fouling Removal Method for a Hull Cleaning Robot

Gharaghani, Pedram | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54350 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Khorasanchi, Mahdi; Durali, Mohammad
  7. Abstract:
  8. The repair, maintenance and cleaning of marine equipment and ships, as well as the optimization of these operations to reduce their costs have always been of interest to researchers. After a few hours of floating in seawater, an inanimate organic layer forms on the surface of marine structures. After a few months, the thickness of this layer increases. This will increase the drag by 30 to 40 percent. Hull cleaning operation increases efficiency, saves time and money, prolongs equipment life and reduces maintenance and repair costs.In this project, the types of marine fouling according to environmental conditions were identified, next a type of fouling (Barnacle) was selected, which has more effect on the surface of ships and marine equipment. In the second phase, the most efficient method of fouling removal was selected by considering the cost, existing challenges and cleaning rate. By performing experimental tests on this method (waterjet system), the necessary data were obtained for validation of the numerical computations. In the third phase, by numerical modeling in STAR-CCM + software, CFD-DEM approach was used to simulate the fouling removal process and finally the effect of important parameters on cleaning speed (jet velocity, nozzle angle, jet length and traverse rate) were studied. The average error of the simulation results compared to the experimental tests was 16.3% (3.4 mm) of Barnacle cleaning width. The most influenced parameters on the cleaning width were: jet velocity output from the nozzle, nozzle angle, the distance traveled by the jet to reach the plate and the traverse rate, respectively.Among 45, 60 and 90 degrees as nozzle angles with the barnacle plate, 45 degree provides the most cleaned width. If the variable parameter is just the distance traveled by the water jet, there is a value as the optimal distance that provides the maximum cleaning width. The Traverse rate parameter had the greatest effect on the amount of Cleaning Rate. The most important error in the problem was the difference in the adhesion of the barnacles, which is due to the adhesion method in the three study environments namely; numerical modeling, experimental and real conditions
  9. Keywords:
  10. Fouling ; Fouling Removal Methods ; Waterjet Cleaning System ; Ship Hull Fouling Removal ; Marine Equipment Fouling Removal ; Computational Fluid Dynamics-Discrete Element Method (CFD-DEM)Simulation

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