Pressure of oil in a pipe?

[Chris313]

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.

 

[waskillywabbit]

All you ever wanted to know about "Flow of Fluids through Valves, Fittings and Pipe" by Crane...most folks know it as Technical Paper No. 410 as it has been around forever and is pretty much an industry standard. I got several free copies not long ago from my local Crane dealer. It is a great reference for any engineer to have.

Brian

http://www.mcabeeconstruction.com

Opinions expressed are my own and are not those of the company.

 

[25362]

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 155^oF, 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.