A centrifugal pump pumps 100 lbs/hr of water 100 ft high to the top nozzle of a distillation column. The pump impeller is 3 ft diameter?
To analyze the given information about the centrifugal pump, we need to determine the pump's power requirement to lift water to a certain height, taking into account the pump impeller diameter.
The power requirement to lift a fluid is given by the equation:
Power (P) = (Flow rate × Head) / (Density × Efficiency)
In this case, we are given the flow rate (100 lbs/hr) and the height (100 ft). However, we don't have the density or efficiency of the pump, so we cannot directly calculate the required power.
To proceed, we need additional information about the pump's efficiency or density. Alternatively, if we assume a reasonable efficiency value, we can still calculate the approximate power requirement for the given conditions.
Once we have the power requirement, we can calculate the impeller speed (RPM) required to achieve the desired flow rate by using the pump's characteristic curve or by using the affinity laws:
RPM = (Flow rate / Impeller area) × (60 / ΔP)
Here, Impeller area can be calculated using the diameter (3 ft) of the impeller:
Impeller area = π × (Diameter/2)^2
Finally, ΔP (Pressure difference) can be determined as the product of the head (100 ft) and the density (provided we have it).
Without additional information like pump efficiency, density, or impeller speed, we cannot calculate the accurate power requirement or RPM for the given conditions.