Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
(OP)
Hi there, I'm having a problem behind the theory of bernoulli's theorem. Can it be applied in an application where water flows from a pump into a pipe with x diameter and out of a nozzle with y diameter to atmosphere. There is a pressure gauge on said pipe. There is a nozzle screwed into this pipe with no pressure gauge on it.
Is the gauge pressure at the nozzle atmospheric pressure, 0 or is it what can be calculated using bernoulli's theorem of conservation of energy?
Is the gauge pressure at the nozzle atmospheric pressure, 0 or is it what can be calculated using bernoulli's theorem of conservation of energy?





RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
MVerrall, not only is that a stupid question, it calls into question your fundamental understanding of the phenomena you are purporting to evaluate.
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
Since the only type of pressure mentioned in the example is gauge, I assume both pressures are given in gauge (that is the only thing that makes sense).
However, if you assume the 400 is absolute and convert the other, that other is said to be gauge, to atmospheric, you can also solve the problem. It's just a different answer.
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
The other form compares conditions at one place to conditions at another. If you have both pressures then you are calculating a differential pressure and gauge or absolute doesn't matter as long as you are sure what you are using.
Even in this form if you are solving for a missing pressure, then the one provided must by in absolute.
So, in 2 of the 3 ways that people use this equation you have to have absolute pressure. The third way is probably the most common form and it can be in either. My approach is to always work in absolute because then I can't get tripped up using gauge in the first or third form.
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
Learn from the mistakes of others. You don't have time to make them all yourself.
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
David Simpson, PE
MuleShoe Engineering
Law is the common force organized to act as an obstacle of injustice Frédéric Bastiat
RE: Bernoulli's theorem of conservation in a nozzle spraying to atmosphere
in order to estimate flow rate with a pump curve, you need TDH. If you were to install a pressure gauge and measure the suction pressure, you could get the TDH. without that, you cannot accurately estimate the flow through the pump (assuming a centrifugal pump). However, even if you did have that it would still only be an estimate. much better to install a flow meter and actually measure the discharge. I can see no reason to go through this exercise to estimate the nozzle coefficient using only estimated flow rates.