Fluid machine for underwater vehicle and underwater vehicle

Abstract

A fluid machine includes: a shaft portion; a shroud having an inside surface with a diameter decreasing from an upstream side toward a downstream side, a flow path being formed between the shroud and the shaft portion and having a flow path cross-sectional area decreasing toward the downstream side; a propeller rotatably provided about an axis between the shaft portion and the shroud and configured to pump a fluid from the upstream side toward the downstream side; and a motor provided to correspond to the propeller and including a rotor having a ring-like shape fixed to an outer circumference portion of the propeller and accommodated in the shroud and a stator having a ring-like shape surrounding the rotor and fixed in the shroud, in which a plurality of the propellers are provided to be spaced apart in the axis direction, the motors are provided in an identical number to the propellers to correspond to each of the propellers, and of a plurality of motors, the rotor of the motor positioned more on the downstream side has a smaller average outside diameter.