Regarding flow velocity calculation
Thread Content
There is a flow rate that represents the velocity through the perimeter of the pipe section; it is related to the Reynolds number in chemical engineering. A value of 1–3 meters per second corresponds to the laminar flow regime. Does anyone know this calculation formula?
http://www.sie.edu.cn/jpk/jpk2007/gcltlx/skja/lljxja/mk4/mk4_4.htm Check if it’s what you need.
Are you referring to things like the hydraulic radius, or the calculation of the Reynolds number for non-circular pipes?
This post was last edited by Shi Xing Long Teng on August 18, 2009, at 11:36. The relationship between the average velocity and the maximum velocity in the cross-section of a circular pipe under laminar flow conditions is: Umax = 2u. The average flow velocity in the pipe cross-section can be derived from the following integral equation: u = △pfR² / 8μL. The type of eddies formed by the fluid within the boundary layer can be determined by the value of Rex; for smooth flat surfaces, when Rex ≤ 2×10⁵, the flow within the boundary layer remains laminar； When Rex≥3×106, it is turbulent ； The value is in the range of 2×105 to 3×106; it could be laminar or turbulent. For laminar flow, the length of the stable section XO is related to the diameter d of the circular pipe and the Reynolds number Re by the formula: XO/d = 0.0575Re, where Re = duρ/μ
You mean the pipe diameter should be appropriate, right?
The original poster should make things clear; take a look at the principles of chemical engineering
If it’s a circular tube, the hydraulic radius is the inner radius of that tube. What I mean is that there’s a formula for calculating flow velocity that uses the perimeter; regardless of the radius, it’s not the area formula that’s used, but rather the perimeter formula
In the principles of chemical engineering, I haven’t seen any calculation of flow velocity using the perimeter; generally, flow velocity is determined by dividing the flow rate by the cross-sectional area of the pipe section. There’s nothing related to the perimeter in 6# zxhxh