Cavitation calculation
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This post was last edited by BoneBrother on 2016-8-26 at 15:55. For our company’s desulfurization unit’s absorption tower, the operating water level is between 7 meters and 9 meters; the liquid surface is in contact with the atmosphere (atmospheric pressure: 101,000 Pa). The slurry temperature is assumed to be 50 degrees Celsius (saturated pressure: 12,327 Pa), and its density is taken as 1,000 kg/m3. The distance from the center of the pump to the bottom of the tower is 2 meters (the pump is above the bottom of the tower). The pressure loss in the pump inlet pipeline is assumed to be equivalent to 1 meter of water column, and the pump’s nominal NPSHr value is 7.9 meters. Calculated using the formula and the minimum liquid level: effective net positive suction head available NPSHa = (101000 – 12327) / 1000 / 9.81 + 7 – 2 – 1 = 13.04 meters; thus cavitation should not occur. Excuse me, is the calculation correct? Thank you.
It seems that it should be: Effective net positive suction head available NPSHa = (101000 – 12327) / 1000 / 9.81 + 7 + 2 – 1 = 17.04 meters. I’m not sure if this is correct :lol
Determine whether the pump’s center is above or below the bottom of the tower. Everything else is fine
How to estimate the pressure loss in the pump inlet pipeline?
The pump is above the bottom of the tank, so it should be deducted when calculating NPSHa – no problem. However, your pump’s net positive suction head available NPSHr is quite high.