Search results
Results from the WOW.Com Content Network
Before being able to use the minor head losses in an equation, the losses in the system due to friction must also be calculated. Equation for friction losses: = [5] [3] [1] = Frictional head loss = Downstream velocity
This dimensionless chart is used to work out pressure drop, (Pa) (or head loss, (m)) and flow rate through pipes. Head loss can be calculated using the Darcy–Weisbach equation in which the Darcy friction factor f D {\displaystyle f_{D}} appears :
Δh = The head loss due to pipe friction over the given length of pipe (SI units: m); [b] g = The local acceleration due to gravity (m/s 2). It is useful to present head loss per length of pipe (dimensionless): = =, where L is the pipe length (m).
The following table gives flow rate Q such that friction loss per unit length Δp / L (SI kg / m 2 / s 2) is 0.082, 0.245, and 0.816, respectively, for a variety of nominal duct sizes. The three values chosen for friction loss correspond to, in US units inch water column per 100 feet, 0.01, .03, and 0.1.
4. The total clockwise head loss in loop 1-2-3 is =. The total clockwise head loss in loop 2-3-4 is =. 5. The value of is determined for each loop. It is found to be 60 in both loops (due to symmetry), as shown in the figure. 6.
h f = head loss in meters (water) over the length of pipe; L = length of pipe in meters; Q = volumetric flow rate, m 3 /s (cubic meters per second) C = pipe roughness coefficient; d = inside pipe diameter, m (meters) Note: pressure drop can be computed from head loss as h f × the unit weight of water (e.g., 9810 N/m 3 at 4 deg C)
This page was last edited on 2 November 2022, at 19:05 (UTC).; Text is available under the Creative Commons Attribution-ShareAlike 4.0 License; additional terms may apply.
In this form the law approximates the Darcy friction factor, the energy (head) loss factor, friction loss factor or Darcy (friction) factor Λ in the laminar flow at very low velocities in cylindrical tube. The theoretical derivation of a slightly different form of the law was made independently by Wiedman in 1856 and Neumann and E. Hagenbach ...