Pressure drop calculations
Pressure drop calculations
(OP)
Hi,
In our shampoo/conditioners plant, we use diaphragm pumps for transferring products from tanks to fillers. Products are in the range of 5000 to 10000 CP viscosity.(depending on temperature)We use 2" food grade pressure hose/pipe for pumping. I guess we are dealing with Newtonian fluids only but pump flow rates are not consistent for different temperatures and viscosities.
Can somebody please give me links to an online pump pressure calculator for Newtonian and Non-Newtonian fluids.
Thanks,
In our shampoo/conditioners plant, we use diaphragm pumps for transferring products from tanks to fillers. Products are in the range of 5000 to 10000 CP viscosity.(depending on temperature)We use 2" food grade pressure hose/pipe for pumping. I guess we are dealing with Newtonian fluids only but pump flow rates are not consistent for different temperatures and viscosities.
Can somebody please give me links to an online pump pressure calculator for Newtonian and Non-Newtonian fluids.
Thanks,





RE: Pressure drop calculations
Link
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.
RE: Pressure drop calculations
diaphragm pumps are in the positive displacement category so shouldn't be that concerned with non Newtonian or not.
Can you explain a bit more with some figures / data?
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop calculations
High pumping pressures are needed when starting up. Once past startup you will probably have to either reduce pump discharge pressure to 1/2 or less, or otherwise deal with increasing flow rates.
RE: Pressure drop calculations
The link is taking me to Google search. Is there any particular website you were referring me to?
Please send me links to calculation pages.
Thanks,
RE: Pressure drop calculations
Sure you need to calculate your max pressure to make sure your pump can supply this, but after that there's no purpose to the calculation - the pump supplies a fixed volume on every stroke providing it gets that amount in on the inlet stroke
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop calculations
As far as controlling the system, pressure obviously affects flow rate, so the key to designing non-Newtonian flowing systems is to realize that the highest pressures will be needed at lowest flow rates (during startup) and you will need a lot less power and pressure as the system approaches design flow rate. Rather than designing only for design flow rate, with non-Newtonian flow it is equally, if not more important, to look at lower flow rates. If you want to try to hold a constant flow rate, these systems can usually benefit from variable speed pumps.
RE: Pressure drop calculations
Thanks for your responses, here are more details:
- Shampoo is to be pumped from 10,000 lit tank- h=3m. (6000 CP at 25 deg C and 9500 at 22)
- 2" pressure hose of 25 ft transfers product to pump. Air at pomp is in the range of 90-100 psi
- Another 2" hose+solid SS pipe+4*90 turns take product to a tank on filler machine (L tot=78 ft)
- This surge tank is kept at 15-25 psi (by air pressure)
- Although pipes go 12 ft high, pump and discharge points are at same elevations
- I cannot get even 7 GPM from this pump.(pump curve is attached)
We have maxed out pressure because available air is not above 110 psi. I'm thinking to put a Pressure 2:1 diaphragm pump and have discharge head double the air pressure, but I'm concerned about hoses and piping.
Should I upsize pipes and hoses? But as I mentioned before some days we get 10 GPM with the same conditions and some days we struggle with even 7 GPM. so, I thought maybe Newtonain, Non-newtonian characteristics cause this.
I appreciate your helps.
RE: Pressure drop calculations
At 7GPM pressures will probably be higher than needed then when at 10GPM. After a while, pressure will drop as velocity picks up. Then flow rates will increase while pressure continues to drop. What you see may depend heavily on when you look.
Some fluids are also dependent on how they have been handled previous entering the pipe and pump system. Some fluids may have a different pressure loss after running through a pump operating at 7GPM and 10GPM because of different shearing characteristics of the pump.
Best to design a system that can handle a multitude of conditions effectively.
You've got to know how your fluid works at all pressures, temperatures and velocities, (shear rates) and if prior handling variations can affect it as well.
RE: Pressure drop calculations
What are your hoses and pipe pressure rated to?
Your viscosity has a big change for only a few degrees so I'm not surprised you're getting a big change on some days and not others.
Making the pipes bigger will help, but how much by is difficult to tell
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop calculations
RE: Pressure drop calculations
Asuuming a 1/1/2 " ID, 10 GPm is only 0.55 m/sec.
BI is on the right lines - find out as much as you can about the stuff you're pumping before you know whether greater veleocity and shear is good for you or not.
Or make sure your hoses and tubes can stand it and pump at 200 psi...
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop calculations
"Then flow rates will increase while pressure continues to drop" is it the case for non-newtonian fluids?
I'm trying to get more data for fluid, but it's not easy. How can I experiment that the fluid is newtonian or non-newtonian or even in some conditions it shows non-newtonian behavior.
I'll find out pressure rating for hose and pipes, most likely in the range of 150 to 200 psi.
Thanks,
RE: Pressure drop calculations
RE: Pressure drop calculations
Let us know when you have some more information
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop calculations
Electric diaphragm pumps are not affected that much by viscosity. The viscosity affects the filling efficiency and if the check valves are not spring loaded or the balls are not heavy, the valves will close a bit slowly with viscous media but all that is in a low percantage range.
RE: Pressure drop calculations
RE: Pressure drop calculations
I can see that from the OPS pump curve, but I will admit I'm not too familiar with these pumps so a good point to make. however he's at a point way to the left of the curve so it's pretty clear to get more flow the issue is not the pressure he's pumping at, but other things. Now it could be he needs more pressure to get the flow rate up and then the pressure will magically fall in which case the flow increases up to a better equilibrium. Or he just needs more pressure and a roughly linear plot will occur.
My only contact with the fluids he refers to is in the shower in the morning so I don't have much more to add....
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Pressure drop calculations
Katmar Software - AioFlo Pipe Hydraulics
http://katmarsoftware.com
"An undefined problem has an infinite number of solutions"
RE: Pressure drop calculations
RE: Pressure drop calculations
I see you have knowledge of the pipe, fittings, elevations and pressures. Do you know the fluid rheology as well? Have you selected an appropriate non-Newtonian fluid model and fit the model to your rheological data? You'll need that to estimate and plot the "system curve". Then, overlay the "system curve" onto your "pump curve". THAT is one way, the easiest way IMO, to give you the answers you want.
Have you used Search (between Forum and FAQs) on this website? I'm sure there are several non-Newtonian threads that may be helpful. Don't limit the search to just this forum. There's non-Newtonian threads in the ChE forums and in Emulsion Engineering. Keywords that may prove useful are non-Newtonian, power law, rheology, shear thinning, shear thickening, Ostwald–de Waele, Bingham, pseudo-plastic, and dilatant.
Good luck,
Latexman
To a ChE, the glass is always full - 1/2 air and 1/2 water.