چكيده به لاتين
A large number of propulsion systems are belonged to vehicles which affect the performance of the propulsion part strongly, such as Underwater vehicles and high speed marine vessels. Nowadays, a vast number of problems are existing in this field which made the topic of development of hydrodynamic design algorithm of underwater high speed vessels propulsion unit as the objective of this research. Propeller based propulsion units are strongly affected by the wake flow of the underwater vehicle. So, a designer must be able to design such a propulsion unit suitable for a special radially variable regime of wake flow. Fixed pitch propellers, ducted propellers, Counter rotating propellers (CRP) and pumpjets are the most important propulsion units which are utilized on underwater vehicles that a designer could select each one with regard to design aspects. This research focuses on CRP and Pumpjet CRP type propulsion units because of some design aspects such as, operating in shallow water, high speed movement, removing the axial torque over the body and low noise propagation. The developed design algorithm uses an iterative method in initial steps in order to make a deep knowledge over design challenges and to obtain an appropriate geometry for the propulsion system and after that applies optmization method based on genetic lagorithm and kriging method over the propulsion unit. In this research, an appropriate geometry of CRP and Pumpjet CRP were obtained using iterative method for an axisymmetric body with a diameter of 500mm and a length of 8m for operating in an advance speed of 55 knots. After that, an optimization process was performed using genetic algorithm and kriging method. The applied tools in this research were a RANS based CFD tool, an FEM tool and MATLAB commercial software as an optimization tool. The hydrodynamic performance of designed propulsion units was 93 percent for operation in a depth of 10m without cavitation.
Keywords: Propulsion unit, High speed underwater vehicle, CRP, Pumpjet CRP.
