某項目冷卻水泵汽蝕余量分析及探討
Analysis and discussion of net positive suction head of cooling water pump in a project
摘要：
對某項目不同方案的冷卻水泵的汽蝕余量進行了分析和探討，指出在當地大氣壓和輸送液體溫度已定的情況下，汽蝕余量的影響因素為冷卻水泵入口與冷卻塔底盤液面的高差和兩者之間的管路阻力。提出了采用壓出式冷卻水泵安裝方式，以及把冷卻塔布置在裙房或塔樓屋頂，利用建筑本身的高度有效克服管路阻力、避免汽蝕現象的措施。建議水管控制流速不大于3 m/s，單個彎頭局部阻力（水頭）小于等于0.5 m。
Abstract：
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.
Keywords:netpositivesuctionhead;coolingwaterpump;press-outinstallation;localresistance;schemeoptimization;velocitycontrol