#### Matt

##### Well-Known Member
Hey
How do you calculate a laminar flow rate through a pipe at a particular pressure...

I'm having trouble just finding the equation.

I know it would have something to do with fluid viscosity, Pressure diffrenetial between the 2 points, fluid density, pipe diameter and the list goes on

Can anyone help me out.

thanks for any help

#### Stones

##### Well-Known Member
If it's any help, I did a search on google for laminar flow and there appears to be quite a bit on it. Just a thought.

#### seo

##### Well-Known Member
What type of fluid?

Do you mean the maximum flow before the transition to turbulent flow?

This is predicted by the Reynolds Number:

Reynolds Number = DVp/u

D = Diamter of pipe
V = average velocity of the liquid
u = viscosity of the liquid
p = density of the liquid

Reynolds numbers above 4000 are usually turbulent flow. Below 2100 is laminar flow. In between the type of flow depends on several variables.

You can reference any Fluid Mechanics Textbook. I referred to McCabe and Smith, Unit Operations of Chemical Engineering, 3rd edition. This is what I had on my shelf from the college days. There are equivalent Mechanical engineering texts as well.

#### illini

##### Well-Known Member
Here's a pretty good web page with what I think you're asking for:

https://www.engineersedge.com/fluid_flow/pressure_drop/pressure_drop.htm

The Reynolds number ranges seo gave for laminar, transitional, and turbulent flow in a pipe are correct. In another thread you'll see I indicated Reynolds number ranges of 30,000 to 100,000 for the boundary between laminar and turbulent flow. Just to be clear, those numbers were for flow over a flat plate. These numbers (2100 to 4000) are for flow in a pipe.

#### Stymye

##### Well-Known Member
Matt, what connection does the formula have to rockets.. would this pertain to tube fins?

#### seo

##### Well-Known Member
Matt-

Are we on the right track here? Did we answer your question?

Scott

#### Matt

##### Well-Known Member
dont worry guys, not really thr forum for the question.

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