| Water-jet propulsion is a type of special ship impetus system. It has many advantages over the other ones, including better cavitation performance than propeller, low noise, good protection, less adjunctive resistence, simple gearing, adaption to off-design condition, good control and position, and so on. Its predominance has been recognised since it has been widely applied on high-performance ship in 1960s.Of the water-jet system water pump is the core component. Cavitation deteriorates the performance of water pump. Thus it is necessary to research on the problerm to improve the performance of pump.With the development of computational fluid dynamics and rapid improvement of computer capacity, it has been possible to research the inner flow inside water pump by numerical simulation.numerical simulation can estimate the parameters that are difficult to measure in experiment. In the analysis and engineering design process of water pump, numerical simulation improves reliability and reduces the cost significantly. Numerical method has become an important tool to design hydromechanical mechanism.According to the requirement of engineering software, program is developed to generate the appropriate data code to describe the basic information of pump and its every blade section of the cascade. When the pump is modeled, FLUENT is imployed to simulate the flow inside, implementing standard k-ε two equations turbulence model ,MIXTURE multiphase model and SIMPLE algorithm method to achieve pressure-velocity coupling. By comparison and analysis, we obtain the distribution of the volume of fraction of the vapour inside pump. Thus we obtain the results on how the bowed blade and sweep blade influence the cavitation of the pump. The results are good reference for engineers majoring on hydromechanical mechanism. |
