This is the equation employed in the spreadsheet.

- ΔP is the pressure loss in the pipe (Pa)
- ρ is the liquid density (kg m
^{-3}) - μ is the liquid viscosity (Pa s)
- g is the gravitational constant (9.81 m s
^{-2}) - L is the length of the pipe (m)
- D is the pipe diameter (m)
- V is the liquid velocity (m s
^{-1}) - f is the Darcy Fanning friction factor

The calculation is iterative, and requires the use of Excel's Goal Seek. However, this is automated in the spreadsheet so you only have to click a button and some VBA initiates Goal Seek for you.

The Darcy-Weisbach equation should only be used for steady-state incompressible flow. It can also be used for open-channel flows by replacing the diameter with the 4 R, where R is the hydraulic diameter. The hydraulic diameter is simply the cross-sectional area divided by the wetted perimeter.

## 0 comments:

## Post a Comment