Two of the most useful and
basic equations are
where
Dh
= Head loss in feet of flowing fluid
u = Velocity in
ft/sec
g = 32.2 ft/sec2
P = Pressure in lb/ft2
V = Specific volume
in ft3/lb
Z = Elevation in feet
E = Head loss due to
friction in feet of flowing fluid
In Equation 1 Dh
is called the “velocity head.” This expression has a wide range of utility not appreciated
by many. It is used “as is” for
1.
Sizing
the holes in a sparger
2.
Calculating
leakage through a small hole
3.
Sizing
a restriction orifice
4.
Calculating
the flow with a pitot tube
With a coefficient it
is used for
1.
Orifice
calculations
2.
Relating
fitting losses, etc.
For a sparger
consisting of a large pipe having small holes drilled along its length Equation
1 applies directly. This is because the hole diameter and the length of fluid travel
passing through the hole are similar dimensions.
An orifice on the
other hand needs a coefficient in Equation 1 because hole diameter is a much
larger dimension than length of travel (say 1/8 in. for
many orifices). Orifices will be discussed under “Metering” in this chapter.
For compressible
fluids one must be careful that when sonic or “choking” velocity is reached,
further decreases in downstream pressure do not produce additional flow. This
occurs at an upstream to downstream absolute pressure ratio of about 2 : 1.
Critical flow due to sonic velocity has practically no application to liquids.
The speed of sound in liquids is very high. See “Sonic Velocity’‘ later in this
chapter.
Still more mileage
can be gotten out of Ah = u2/2g when using it with Equation 2, which
is the famous
Bernoulli equation.
The terms are
1.
The
PV change
2.
The
kinetic energy change or “velocity head”
3.
The
elevation change
4.
The
friction loss
These contribute to
the flowing head loss in a pipe. However, there are many situations where by
chance, or on purpose, u2/2g head is converted to PV or vice versa. We
purposely change u2/2g to PV gradually in the following situations:
1.
Entering
phase separator drums to cut down turbu lence and promote separation
2.
Entering
vacuum condensers to cut down pressuredrop
We build up PV and
convert it in a controlled manner to u2/2g in a form of tank
blender.
Here are various recommended flows,
velocities, and pressure drops for various piping services.
2 komentar:
Sometimes, I use only fluid velocity as an approach to estimate pipe size. So far so good, it works, without given any allowance for the value. Could you mention the source of all the tables? Thanks.
🇧🇷🇮🇴🇻🇬🇧🇦🇧🇴🇧🇹🇧🇪🇧🇿Highly Recommended!
Very insightful, i will also say this here. Investment is one of the best ways to achieve financial freedom. For a beginner there are so many challenges you face. It's hard to know how to get started. Trading on the Cryptocurrency market has really been a life changer for me. I almost gave up on crypto at some point not until saw a recommendation on Elon musk successfully success story and I got a proficient trader/broker Mr Bernie Doran , he gave me all the information required to succeed in trading. I made more profit than I could ever imagine. I'm not here to converse much but to share my testimony; I have made total returns of 3.6BTC from an investment of just 0.6BTC. Thanks to Mr Bernie I'm really grateful,I have been able to make a great returns trading with his signals and strategies .I urge anyone interested in
INVESTMENT to take bold step in investing in the Cryptocurrency Market, you can reach him on WhatsApp : +1(424) 285-0682 or his Gmail : BERNIEDORANSIGNALS@GMAIL.COM, bitcoin is taking over the world, tell him I referred you🇧🇯🇧🇧🇧🇩🇦🇹🇦🇿🇦🇲🇦🇷
Post a Comment