That's a water impeller that goes inside a water pump.

它个排水叶轮，放在水。

Three large impeller fans quietly channel air from front to back, while a blower pulls heat from the memory.

三个大型叶轮风扇悄然将空气从前部导到后部，而一个鼓风机则带走内存散热。

The pump is a brushless DC motor constructed from a PCB, a control chip and a stator on the dry side, a barrier in the middle, and then the permanent magnet rotor and impeller on the liquid side.

一个无刷直流电机，由干侧PCB、控制芯片和定子，中间屏障， 以及液侧永磁转子和叶轮构成。