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Ounaghi, Mohammad Safa | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 42772 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Abbaspour, Madjid
  7. Abstract:
  8. In order to design a ship with waterjet system, estimation of its hydrodynamic performance is crucial. Presence and operation of waterjet propulsion system changes the flow field and pressure distribution in bottom and stem of ship hull, so affect hydrodynamic performance of craft. In the present thesis, CFD analysis is applied to free surface flow around a waterjet propelled ship using ANSYS CFX software. Also a waterjet propulsion system is built and settled in a ship model and resistance and self propulsion tests are performed. In order to performing a systematic process in project, in the first step, pump design is performed with extracting optimum efficiency relations and cavitation parameters. Then one phase flow analysis is performed on the designed inlet. In the next step, waterjet inlet and pump components are built with casting. After that self propulsion tests is performed for calculation of drag, trim and sinkage. One phase flow analysis on inlet area show that with raise of IVR value, cavitation probability in cutwater area first decreases and then increases. For free surface flow analysis, flow field calculations are performed in bare hull and with and without waterjet operation conditions. In order to surveying effects of inlet presence and waterjet operation on flow field around the hull, qualitative results in mentioned three states are compared with each other. It is obtained from comparisons that wave making resistance in operation condition increase. Also pressure distribution in duct show that probability of flow separation occurrence is raised in operating condition. In addition, time series resistance diagram is extracted in each condition. These diagrams show that mean value resistance increase in waterjet operating condition. Comparison of numerical and experimental resistance diagrams in three test condition show acceptable results as Maximum error %13 is seen in waterjet operational condition. Main causes of this error may be difference in degrees of freedom between numerical and experimental and device errors
  9. Keywords:
  10. Model Test ; Towing Tank ; Free Surface Flow ; Waterjet ; Waterjet Propulsion ; Inlet ; Self Propulsion Test ; Axial Pump

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