In your calculations you have assumed zero slip between the flash steam and the condensate flowing in the 2" pipe. It will not be like that. The condensate will flow at a slower velocity than the steam. Also, the condensate does not flow in a nice neat discrete layer at the bottom of the pipe...
Whether we are looking at a centrifugal pump curve together with its system curve, or as in this case where we are looking at an ejector curve and a system curve all they are is a graphical technique of solving two simultaneous equations. I have used this graphical technique and you have done...
This seems to be a logical statement but it would make the performance of the exhauster look worse and the supplier will want to present their product in the best possible light so I doubt whether they would include these corrections. The only way to be sure would be to check with the supplier...
I did not pick up that the vacuum of 3"Hg was measured at zero suction flow with the inlet blanked off. I feel a bit better seeing that Snickster also missed it initially but when my earlier calculation fell so far off the curve I should have been more suspicious.
Anyway, we are now in a...
In a typical fluid flow situation there will be pressure changes caused by the Bernoulli effects (velocity changes) and also losses caused by friction. Depending on the situation, one of these may be dominant and the other can be ignored without introducing too much error. In your situation, by...
That depends on how many of the 20 you want to be able to use at the same time. That is why these valves are rated for 14 bar. If you have fewer valves open the pressure will increase (assuming you are using a centrifugal pump). If you decide that the most valves you want open at the same time...
Your sketch is exactly what I had in mind, so we are talking of the same problem now.
In line with the principle of conservation of mass, if the pump is delivering 900 LPM and there is only 1 spray nozzle open then there must be 900 LPM flowing out of that valve. The problem of getting balanced...
Without a sketch of what is confusing you, I am also a bit confused. There are two separate aspects to this calculation. The first is the system consisting of the fire water pump, the piping to the landing valve and the landing valve itself. It might well be that the piping is a ring main or a...
The pressure at the hydrant (sometimes called residual pressure) is required to generate sufficient velocity in the monitor or nozzle that will be used to fight the fire. The velocity from a fire fighting nozzle will typically be 25 to 30 m/s to allow the sprayed water to reach a reasonable...
I have not worked through the article in detail but it looks questionable to me and I would advise you to compare it with other sources.
I agree with Latexman and TiCl4 that gc is wrong. And it is wrongly described in the article as being the gravitational constant, which it is not (although it...
The residence time is a function of only the volumetric flowrate and the volume of the oxidizer, so you have no need to measure the density.
All you want to measure is the volumetric flowrate - regardless of what the density is. This makes a laminar flow meter the obvious choice. It is a...
You need to take a step back and look at the bigger picture.
Why do you want to measure the flowrate? Does the flow to the oxidizer need to be varied according to the organic content of the off-gas? If yes, how will you measure the organic content? If you do measure the organic content then you...
If you are talking of just the manifold section where the branch pipes connect into then I am with you on the 36" section. I took it as the size for the complete header and 36" is unnecessarily big for that. But for the short section where the other branches need to be connected into having it a...
Rules of thumb (ROTs) are useful as starting points for iterative calculations but using them for real design is wasteful at best and dangerous at worst.
The total flowrate of 1069 kg/s in a 36" pipe would give a velocity of 1.7 m/s and a pressure drop of 2.0 kPa/100m (0.1 psi/100ft). Unless...
If the coolers are all close together the individual branch lines will be short and designing on the basis of velocity will give you a safe design, but you might be able to get away with smaller diameter pipes.
For example, if the line to Cooler 6 is 20" Sch 40 then the velocity would be 2.4...
To answer your original question - the operating point must fall on or below the "including conductance" curve.
As I stated earlier, I have not worked with these conductance curves before, and although the Leybold web page is quite comprehensive it is a nightmare of unit conversions, nomograms...
According to the reference LittleInch gave, the conductance is not the pressure drop but it is the multiplier that must be applied to the pressure drop to calculate the flow rate in volumetric terms.
Under vacuum conditions the density of the gas is usually low enough to ensure that the...
I see that while I was typing up my rant, Pierre has posted a perfect example of what I was getting at.
Each branch of hydraulics, from fire water to vacuum systems, developed their own arcane terminology and methods of problem solution. Back in the day this allowed them to solve routine...
If the main pipe is 41 m long and 25 NB Sch 40 then I would agree with the supplier that it is too small.
But first, a rant. Whenever volumetric flows of gas are given it is essential that the basis be given with the flowrate. It is meaningless to say 60 m3/h without stating whether it is free...
I strongly suspect that the X-axis on the charts is the pressure in mbara and not the pipe length. I see in both cases the operating point is at an X value of 15 and this corresponds to the pressure and not to the pipe length.
I have not seen this type of chart with the two curves before. You...
