Pressure of oil in a pipe?
Pressure of oil in a pipe?
(OP)
I work with processing Transformer Oils. This Oil is typically about 0.88 or 0.89 in specific gravity. I am wondering how to calculate the pressure in a given part of the piping system, when the temperature and the flow rate in gallons per minute, and the inside diameter of the pipe are known. As an example, If the oil is heated to 155 degrees F, and flows at 25 gallons per minute, through a pipe that has an inside diameter of 1 inch, what pressure would be produced where the oil enters the part of the system that is reduced to 1 inch. Any help in understanding how to calculate this, or how I might find some information on a problem / solution of this nature would be greatly appreciated.





RE: Pressure of oil in a pipe?
Brian
www.mcabeeconstruction.com
Opinions expressed are my own and are not those of the company.
RE: Pressure of oil in a pipe?
Besides the data in hand, you need to know the viscosity and the sp. gravity of the oil at the running temperature to estimate the pressure drop per ft of pipe.
To give you an idea. If the 25 gpm of the running oil has sp. gravity 0.85 and its viscosity is 5 cS, all taken at 155oF, in a 1" nominal (sch 40) pipe, the pressure drop for 100 ft of straight pipe would be about 17 psi. The linear velocity being ~9.3 fps.
If you also have pipe fittings you should add their friction drop to that figure.
You must be sure of the temperature because it affects the viscosity in such a manner that, if, for instance, the viscosity rises to, say, 100 cS, the pressure drop would increase to about 45 psi per 100 ft.
Any book on hydraulics can be helpful.