What happening when low pressure and high flow rete?
What happening when low pressure and high flow rete?
(OP)
For the piping with equal size along the single piping system.
1. Is the flow rate is equal along the piping system ?
(A1V1 = A2V2)
2. If the answer from first question is ture. Flow rate at the end of piping system is equal to the flow rate at the first point of piping system but have more pressure drop along this piping system. and then What happen in this even?
1. Is the flow rate is equal along the piping system ?
(A1V1 = A2V2)
2. If the answer from first question is ture. Flow rate at the end of piping system is equal to the flow rate at the first point of piping system but have more pressure drop along this piping system. and then What happen in this even?





RE: What happening when low pressure and high flow rete?
2. It is not true, so I guess I don't have to try to puzzle out what the heck you are talking about.
David
RE: What happening when low pressure and high flow rete?
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: What happening when low pressure and high flow rete?
RE: What happening when low pressure and high flow rete?
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: What happening when low pressure and high flow rete?
RE: What happening when low pressure and high flow rete?
I think Goblintechnic meant V=Velocity. Volumetric Flow = Cross Section Area x Velocity.
Other than that I can only speculate that goblintechnic wanted to know:
If volumetric flowrate at point 1 equals to that of point 2, and the fluid experiences pressure drop between the two points, the fluid expands. Where does the extra volume go?
Answer - if there is a pressure drop across a pipeline, then the volumetric flow entering and exiting cannot be the same without energy being added into the fluid or mass being taken out of it.
NH Liew
RE: What happening when low pressure and high flow rete?
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: What happening when low pressure and high flow rete?
RE: What happening when low pressure and high flow rete?
zdas said it first, but I thought it needed restating.
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: What happening when low pressure and high flow rete?
Bernoulli's equation states that for inviscid, non rotational and incompressible fluid the total head H along a streamline is constant
H = z + p/(rho*g) + V^2/(2g) = const
Where:
p is the pressure,
V = the average fluid velocity,
rho = the fluid density,
z = the pipe elevation
g= the gravity acceleration constant.
For a real viscous fluid streamline, part of the energy is turned into heat and lost, and pressure drop between two points of the streamline is the energy difference between the aforesaid points.
So pressure drops intervene in a balance energy equation, without affecting mass conservation (continuity equation).
RE: What happening when low pressure and high flow rete?
rmw
RE: What happening when low pressure and high flow rete?
I must apologize for neglecting to mention that my comment was based on gas flow.
Having P1>P2, it follows that the gas at Point 2 expands, i.e. there is a reduction of density. Therefore Qa2(actual volumetric flowrate)>Qa1. This being said, mass flow (kg/s) and volumetric flow in standard conditions (std ft3/s) remain the same.
Going forward, Qa1=A1V1 and Qa2=A2V2. Since cross section area remain the same A1=A2, then V2>V1.
However, I am simplifying the equation to the extent of assuming constant temperature and compressibility factor (z).
RE: What happening when low pressure and high flow rete?
nhliew, It applies to liquid flow also, just the effects are not so pronounced as in gases. The only basic difference between liquid and gas P-V relationship is the magnitude and the shape of the "z" curve. A very small change in a fluid's volume results in a very large change in pressure, or v/v.
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: What happening when low pressure and high flow rete?
For these fluids and from Hugoniot theorem:
dA/A = (M^2-1)* dV/V
where A = transverse area of the pipe
dA = transverse area variation
M = Mach number
V = fluid velocity
dV = fluid velocity variation
If the fluid expands (that is it accelerates) dV/V>0 in a subsonic regime (M<1) the section must contract (dA/A<0)
If the fluid expands (that is it accelerates) dV/V>0 in a supersonic regime (M>1) the section must increase (dA/A>0)
If the fluid contracts (that is it decelerates) dV/V<0 in a subsonic regime (M<1) the section must increase (dA/A>0)
If the fluid contracts (that is it decelerates) dV/V<0 in a supersonic regime (M>1) the section must decrease (dA/A<0)
If M = 1 the section must be constant (dA/A=0)
RE: What happening when low pressure and high flow rete?
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/
RE: What happening when low pressure and high flow rete?
I'd like to meet you as you're not only very skilled, but you've also an innate sense of humour, whilst here in Italy engineers are usually quite humourless.
RE: What happening when low pressure and high flow rete?
But really I don't think lack of humor is necessarily a fault of engineer's themselves, but more of engineering work, which lacks latitude and freedom for the expression of humor, as most people know it. Engineers themselves do have a sense of humor; its just "different" when compared to "normal people's" sense of humor. We're just a very misunderstood lot.
I think this is a good example of what I mean. When I was little I asked my father what the difference was between AM and FM radio. My dad told me that FM stations were in New York. When I finally learned what the difference really was, at first I was mad at my father for having lied to me, but when I got over it, I thought that was one of the funniest things that he ever did having that joke on me and waiting another 15 years for me to get it. He was a metallurgist. Then I found out he did it again with that thing about F=MA that really should be E/c^2 * A So much for engineering humor. And yes ... I am also afraid that I am an exception to just about every (non-thermodynamic) rules. You've just seen the tip of the iceberg.
Globalintechnic, sorry for the attempted hijack.
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"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/