Hydrodynamic analysis of a novel thruster for amphibious sphere robots

Four novel thrusters as the actuator of amphibious spherical robots play an important role. The resultant force of four thrusters is the main driving force of the robot. In order to achieve better control of the amphibious spherical robots, it is necessary to analyze the effects on the propelling force of the novel thruster. This paper utilize Computational Fluid Dynamics (CFD) to simulate hydrodynamic behavior of the new thruster and analyze the thrust force with different rotating velocity and inlet velocity. Further, as the inlet velocity is susceptible by the rotating velocity, we defined advanced coefficient with inlet velocity and rotating velocity. We analyze the thrust force and efficiency with different advanced coefficients. The result shows that the thrust force is more sensitive to rotating velocity of blades than the inlet velocity. The curves also show that the efficiency traces a downward parabola with the advanced coefficient. According to the simulation results, I should keep the advanced coefficient at 0.6 as our best as possible to take full use of the energy. Thus, these results provide foundation for the mathematical model building.