Interested to Buy Any Domain ? << Click Here >> for more details...
what is npsh and how to calculate it for a centrifugal pump
- 15 Answers
- 47829 Views
- Essar, I also Faced
- E-Mail Answers
Answer Posted / nasser khattab
Given:
• Atmospheric pressure = 14.7 psi
• Gage pressure =the tank is at sea level and open to atmospheric pressure.
• Liquid level above pump centerline = 5 feet
• Piping = a total of 10 feet of 2 inch pipe plus one 90° long radius screwed elbow.
• Pumping =100 gpm. 68°F. Fresh water with a specific gravity of one (1).
• Vapor pressure of 68°F. Water = 0.27 psi from the vapor chart.
• Specific gravity = 1
• NPSHR (net positive suction head required, from the pump curve at 100 gpm) = 9 feet
Now for the calculations:
NPSHA = Atmospheric pressure(converted to head) + static head + surface pressure head - vapor pressure of your product - loss in the piping, valves and fittings
• Static head = 5 feet
• Atmospheric pressure = pressure x 2.31/sg. = 14.7 x 2.31/1 = 34 feet absolute
• Gage pressure = 0
• Vapor pressure of 68°F. water converted to head = pressure x 2.31/sg = 0.27 x 2.31/1 = 0.62 feet
• Looking at the friction charts:
o 100 gpm flowing through 2 inch pipe shows a loss of 17.4 feet for each 100 feet of pipe or 17.4/10 = 1.74 feet of head loss in the piping
o The K factor for one 2 inch elbow is 0.4 x 1.42 = 0.6 feet
• Adding these numbers together, 1.74 + 0.6 = a total of 2.34 feet friction loss in the pipe and fitting.
NPSHA (net positive suction head available) = 34 + 5 + 0 - 0.62 - 2.34 = 36.04 feet
The pump required 9 feet of head at 100 gpm. And we have 36.04 feet so we have plenty to spare.
| Is This Answer Correct ? | 6 Yes | 0 No |
Post New Answer View All Answers
What is comprehensive definition of compressor surging
What is the principle of mechanical refrigeration ?
What causes a hydraulic cylinder to skip?
State fresh water generation plant made water flow.
How do you measure the moment of inertia?
Explain the formation of micro structures of pearlite, bainite and martensite in steel?
What is the date of first titan launch from cape canaveral?
Why do the radiators in your house click when you start the heating system?
Disposal of radioactive waste materials and spent fuel is a major and important technology. How the waste radioactive material is disposed off ?
Explain how the cylinder lubrication on main engine is done?
Explain important rules that must be kept in mind while designing castings?
How can we calculate the per hour productivity of a hydraulic rock breaker,for excavator..
What are the rules that must be kept in mind while designing castings?
What is the effect of inter cooling in gas turbines ?
Name two vital conditions of a perfect gas.
