what is npsh and how to calculate it for a centrifugal pump
Answer Posted / saravanan
NPSH is Net Positive Suction Head.. As the name indicates
it is the Positive suction head that should be necessarily
available at suction to prevent the liquid from boil up due
the vapor pressure of the liquid at pumping temperature. It
is also said as the Head necessary at the suction to over
come the vapor pressure of the liquid at pumping
temperature.
Liquid if pumped at low pressure & high temperature (close
to boiling point) nullifies vapor pressure and cavitates.
NPSH available should always be greater than NPSH required
defined by the pump vendor (NPSH R is function of the pump
impeller geometry) to get improved performance.
NPSH available = Suction Pressure - Vapor Pressure + Static
Head - Frictional loss across the suction line.
Since the velocity at the suction is minimum, dynamic head
can be ignored. Hence the only deciding factor is Static
Head, Suction pressure & Operating Temperature..
Higher the static head, higher is the suction pressure &
lower is the pumping temperature better would be the NPSH
avaialble at the impeller eye.
| Is This Answer Correct ? | 37 Yes | 11 No |
Post New Answer View All Answers
what will be the minimum bearing clearance that after it will not profitable for machines?
Who built the tr alaska pipelene?
What are the requirements of a good fuel?
plz sent me jindal placement papers in mechanical enginnering
which technology use in bikes
What is the indication of leaking starting valve of an engine?
what is the rpm of Turbocharger of Cummins KTA50G3 Diesel Engine?/ Normally What is the rpm of Turbocharger for any 1 MW Engine?
Name Of Parts And Each Purpose
What type of paper when made into a paper boat floats longest?
Explain how to clean LO
Is critical speed temperature dependent or speed dependent or both?
respected sir, i had applied for the post of GET for JSPL so kindly send me the syllabus and exam pattern for the concerned examination. my mail id: starsunny49@gmail.com thanking you sir
hello, this is sai preparing for mvi exam if any having previous year question papers please help me out
draw p-v dia distingshing naturally aspirated and supercharged engine with reference to pumping loss?
Is your basic salary of $...... , good for you if employed?In case of any eventuailt,who is your next of kin?