As daar kavitasie vir sentrifugale pompe is, kan dit vibrasie en geraas veroorsaak tydens die daaglikse werking daarvan, soms moet ons dalk ophou werk. Ons moet dus uitvind watter soort redes tot die kavitasie vir sentrifugale pompe sal lei, dan kan ons hierdie vrae op 'n baie slim manier vermy.
The cavitation of centrifugal pumps, or the cavitation , is a process for flow liquid bubbles and then burst. When the absolute speed of flow liquid increase, as the static pressure of flow liquid decrease, for certain particle at a certain temperature of the fluid , although there is no heat from external input, but they have reached the vapor pressure, so that particle vaporization, and the bubble generated. Along the flow path.
As die statiese druk van die vloeistof weer verhoog word, hoër as die dampdruk, sal die borrel baie vinnig bars. 'n Groot deel van die kondensasie-implosie-impak. As die borrel bars wanneer dit nie in die vloei van die vloeistof is nie, maar in die wand van die geleidingsonderdele, sal kavitasie daartoe lei dat die nat dele aan erosie blootgestel word.
Wanneer die sentrifugale pomp onder kavitasietoestand werk, selfs al is daar geen erosie van nat dele nie, kan jy ook vind dat die geraas van die sentrifugale pomp op hierdie tydstip baie groot is, vibrasie toeneem, doeltreffendheid afneem en die druk dienooreenkomstig baie laag word.
The equipment NPSHa , also called as effective NPSH. The equipment is provided by suction equipment, in the suction position of centrifugal pump, unit weight of the liquid have surplus energy more than vaporization pressure and head . Overseas call this an effective net positive suction head, That pump inlet (head position is zero) with a full head of liquid minus vaporization pressure and the net surplus value, represented by NPSHa. Its value and parameters related to liquid properties. Because inhalation device is proportional to the square of the flow and hydraulic loss. So NPSH decreases with the increase in capacity. NPSH-Q is a decreasing curve. The NPSH have relationship with the flow condition of pumps, it was balance pump inlet pressure drop decided by centrifugal pump itself. That is to say, in order to avoid the cavitation for the pump, we require that there is extra energy that could exceed vapor pressure head in the pump inlet. Overseas call this a required net positive suction head. The physical meaning of the pump NPSH indicates the degree of pump inlet pressure drop of the liquid. The so-called net positive suction head required, It is to require the inhalation device must be provided such a large net positive suction head, in order to compensate the pressure drops, to ensure that the pump cavitation does not occur.
NPSH van meerstadium-sentrifugale pompe het geen verband met toerustingparameters nie. Slegs verwant aan bewegingsparameters in die pompinlaat. Bewegingsparameters teen 'n sekere spoed en vloeiparameters word deur die geometrie bepaal. Dit wil sê, NPSH word deur die pomp self bepaal. Vir 'n gegewe pomp, ongeag die vloeistof, teen 'n sekere spoed en vloei deur die pompinlaat, dus, as gevolg van dieselfde spoed, het hulle dieselfde drukval, dieselfde NPSHr. Dus het NPSHr geen verband met vloeistofeienskappe nie. Hoe kleiner die NPSH, hoe kleiner die druk.
Ti vereis dat die toerusting kleiner NPSHa moet bied, en dan 'n beter weerstand teen pompkavitasie.
