Analysis and discussion of net positive suction head of cooling water pump in a project

 This paper analyses and discusses the net positive suction head (NPSH) of different schemes of the cooling water pump of a project， and points out that the influencing factors of NPSH are the height difference between the inlet of the cooling water pump and the liquid level of the cooling tower bottom tray and the pipeline resistance between them when the local atmospheric pressure and the temperature of the transmitted liquid have been determined. This paper proposes the installation method of press-out cooling water pump, and the arrangement of cooling towers on the podium or the tower roof to effectively overcome the pipeline resistance and avoid cavitation by using the height of the building itself. It is recommended that the flow rate of the water pipe is not be greater than 3 m/s, and the local resistance (water head) of a single elbow is less than or equal to 0.5 m.