Ways to Calculate Reynolds Number

reynolds number=(ρ(density)*v(speed)*d)/μ

ihope to aid you

Dear Macsimus,

I noticed that all your threads are related to mechanical engineering, and you are graduated from college in May, 2007 holding a Bachelor Degree in Electronics and Instrumentation Engineering.

So, it will be difficult for you to learn the mechanical engineering from zero through the posts of CR4.

To adapt the usual formula for Re which considers a round area the notion of "hydraulic" diameter was introduced

dh= (4*A/P)^0.5

A= area of the considered section in your case it is the ring

P= perimeter of the area in your case the 2 circles limiting the ring

With this relationship you can use the general computation equation as indicated in an other comment.

I p)resume that you are able to do the computations by your self since we are not here to make your work but only to help you come out of troubles.

With respect to the other parameters as cinematic viscosity or dynamic viscosity and specific weight you can help your self in the different manuals of physics

In order to <...Calculate Reynolds Number...> one also needs the viscosity of <...Nitrogen...> at <...7 Bar Operating Temp 35Deg C...>.