If you scale the length then you must adjust other properties. If you have not learned the theory of this then don't attempt the job.
There is a reason why people spend years studying engineering at university.
Jhon, I think the answer was as simple as saying "similarity and dimensional analysis", but.... thanks for trying to respond.
I use my fluids textboox from college: "Fundamentals of Fluid Mechanics," Bruce Munson, Donald Young, Theodore Okiishi, 4th Edition, copyright 2002.
Chapter 7 tells you how to do Similitude, Dimensional Analysis, and Modeling.
Hope this helps,
David is correct. You should scale the rest of the fluid parameters based on the Reynolds number of the flow. The text
he mentions (Munsun, et. al.) goes through the non-dimensionalization process in section 7.10. However most undergraduate
fluids texts will have a section on this topic.
Its not trivial but far from impossible. Take a stab at it and let us know how it works out!
If it were me, I would do a short straight model and figure out the pressure drop per unit length for the straight sections (including a long enough start up section to ensure a fully developed velocity profile) and some suitable test section length. I would then asses the pressure drop contributions due to the frequently occuring bends - 90°, 45° or whatever is present. Then add it up. It would avoid scaling issues all together. Then again a hand calc might be quicker and possibly better using the RAND book on piping losses or some other suitable reference. Finite volume codes of FS's type are not particularly well suited to such extreme aspect ratio problems, assuming the pipe ID is very small compared to the length.