Blade tip geometry modifications to energize the centerline flow through the Rim Driven Thruster

Unlike a conventional thrust-producing fan, which is driven by a shaft located along the centerline, rim driven thruster blades are actuated into a rotational motion at their outer radius. In such a configuration, blades are attached to the outer rim and extend toward the center leaving an unobstructed flow through the centerline region. Previous investigations of the velocity field downstream of a rim driven thruster prototype showed the existence of an accelerated fluid stream in the centerline. In the current study, a numerical simulation is performed to confirm the presence of the accelerated flow region. An attempt is made to modify the blade tip geometry to further energize the flow in the centerline and increase thrust.