A centrifugal pump and a gear pump are operating in series in a closed loop to deliver a 20% ethylene glycol solution at an average temperature of 10°C through a long pipe system. In the capacity range up to 2 m3/s, the pump performance equations expressed in terms of pressure increase as a function of capacity are given by,

A detailed friction analysis reveals that the pressure drop through the closed loop system is given by,

In the equations above, the pressure changes are in kPa and the capacity is in m3/s.

a. On the same plot, show the system curve, the performance curves for each pump, and the performance curve of the combined series pumps in terms of head (m) as a function of capacity (m3/s). Draw the curves from 0 to 2 m3/s.

b. Write a simulation of the system and determine its operating point.

c. If the economic velocity of the ethylene glycol solution for this system is 2.9 m/s, specify the standard schedule steel pipe required for this application.

Transcribed Image Text:

centrifugal pump: gear pump: AP = 50+ 0.2V-10 AP=30-10-