Question

The whey obtained from centrifugation to extract some proteins is stored in a preliminary tank and subsequently pumped at a rate of 20 L / s to the general storage tanks, to be used in other processes. The starting tank and the storage tank are kept at atmospheric pressure and the difference of 10 m in height that exists between the whey in each tank is constant. The total length of pipe in the suction line is 5 m with a standard 4-inch diameter and absolute roughness equal to 0.00125 m. The discharge length is 25 m with a diameter of 6 in and the same roughness. Consider the vapor pressure of the whey similar to that of water at 30 ° C (4243 Pa).

The density of the whey at operating conditions is 1027 kg / m3
The viscosity of the whey can be considered 0.0012 Pa * s.
The valves and accessories that are installed in the system's piping system are:
Accessory type

Resistances (K) for each accessory

2 Standard 90 ° elbows = 0.75

1 gate valve at the pump outlet = 0.17

1 globe valve fully open at the pump inlet = 10

Centrifugal tank inlet to pipeline = 0.5

Inlet from storage tank to pipeline = 0.6

Determine the following parameters:
a) Fluid velocity in the piping system (suction and discharge)
b) Energy losses due to friction in pipes (suction and discharge)
c) Reynolds number (suction and discharge).
d) Value of the friction factor (suction and discharge).
e) Friction energy losses in valves and accessories (suction and discharge).
f) Determine the NPSH available and required for the system
g) Pressure drop in the system.
h) Dynamic load of the system that the pump must deliver to propel the fluid from section A to section B shown in the figure.
i) The power received by the liquid, supplied by the pump.
j) The motor power, considering an efficiency of the motor-pump set of 60%.

Answer 1

Please refer the following images for the solution.