Pressure in a vertical tube results in a displacement of the fluid without regard to tube diameter. Piping networks tend to include several turns and elbows in order to deliver the fluid. Le is the equivalent length of straight pipe and is found in tables and figures based on tube diameter and the turn radius. D is the tube diameter and V is the mean fluid velocity, which is found based on venturi pressure drop from charts supplied by the manufacturers of the venturi meter and valve controls. The Kc can be found in reference texts based on the direction of fluid flow and the cross-sectional area.
L is the length of the pipe.
The sum of the individual loss elements is the total system head loss. So, you see, these equations help relate the data we gathered into performance characteristics for our system. Next, we'll see what these results look like and draw some conclusions.