Hydraulic circuits (water) : serial & parallel orifices
Hydraulic circuits (water) : serial & parallel orifices
(OP)
Good Morning!
I have a question concerning the water flow in a hydraulic
system. In different positions of the system, I have
to install sharp edged orifices to regulate the mass flow.
Now I am searching for a good approach for testing & calculations.
For the orifice, I determine the pressure drop as a function of the mass flow by experiment and then
calculate the discharge coefficient Cd=m./(A0*sqrt(2*rho*DP))
with
CD=discharge coefficient [/]
m. = mass flow dm/dt [kg/s]
A0 = orifice area [m**2]
rho = water density (function of temp) [kg/m**3]
DP = pressure drop [Pa]
What happens now if I install two orifices in parallel/serie
al connection?
Is it possible to calculate with discharge coefficients or is there a better way?
Thanks in advance,
Stephan
I have a question concerning the water flow in a hydraulic
system. In different positions of the system, I have
to install sharp edged orifices to regulate the mass flow.
Now I am searching for a good approach for testing & calculations.
For the orifice, I determine the pressure drop as a function of the mass flow by experiment and then
calculate the discharge coefficient Cd=m./(A0*sqrt(2*rho*DP))
with
CD=discharge coefficient [/]
m. = mass flow dm/dt [kg/s]
A0 = orifice area [m**2]
rho = water density (function of temp) [kg/m**3]
DP = pressure drop [Pa]
What happens now if I install two orifices in parallel/serie
al connection?
Is it possible to calculate with discharge coefficients or is there a better way?
Thanks in advance,
Stephan





RE: Hydraulic circuits (water) : serial & parallel orifices
If I understand the question......
In a similar situation I built a manometer an pipe taps and measured the differential pressure across the orifice plates. with known flowrates you can back out the discharge coefficient(s).
Tom
RE: Hydraulic circuits (water) : serial & parallel orifices
Your suggestion is in fact that what I am doing first:
I have a batch of approx. 100 different orifices from
0.05 - 0.1 in diameter. Then I will perform one
delta p measurement at one fixed mass flow - for
example at 0.7 GPM - resulting in an discharge coefficent
(see formula from my first post) for each orifice.
Later on, when I have to do an initial setup of a new facility, I have to select an appropriate orifice.
If the orifice I am looking for is not available,
is it perhaps possible to do a series connection of two
orifices?
How should I then perform the calculation?
Cd (total) = Cd.1 * Cd.2, like I do for efficincy factors?
Thanks in advance,
Stephan
RE: Hydraulic circuits (water) : serial & parallel orifices
I spent all day yesterday soaking wet trying to solve a similar, though not quite as interesting, problem. I would like to hear what your findings are.
Tom
RE: Hydraulic circuits (water) : serial & parallel orifices
I will do that. In one ore two weeks I will post the results; I have lots to do at the moment and this is not my main task.
Greetings,
Stephan