Table 1 Parameters used to calculate the functioning of the Barbegal mill wheels and elbow flume.
Parameter | Description | Value |
|---|---|---|
g | Gravity acceleration | 9.81 m/s2 |
Parameters for the basins | ||
Lup | Internal width of a millwheel basin | 1.10 ± 0.05 m |
Hup | Water depth in the basins | variable [m] |
Qup | Discharge (flow rate) through a basin | variable [m3/s] |
Parameters for the elbow flume | ||
Hf | Water depth at the end of the flume | variable [m] |
L | Internal width of the flume without deposits | 0.30 ± 0.02 m |
Hc | Critical depth for the flume | calculated from Qf and L (Eq. 1) [m] |
Ks | Strickler roughness coefficient of the flume | 70–90 [m1/3/s] |
Vinlet | Inlet velocity of water into the flume | based on Hc and Qf (critical flow) [m/s] |
Vf | Flume outlet velocity | variable [m/s] |
Qf | Discharge (flow rate) in the flume | variable [m3/s] |
Parameters for the wheel | ||
D | Diameter of the wheel | 2.0 m |
B | Outside width of the water wheel | 0.85 m |
b | Effective internal width of the buckets | 0.75 m |
Nc | Critical velocity of the wheel rim | 29.9 rpm (D = 2 m) |
Nw | Velocity of wheel rim when in operation | variable [rpm] |
Vw | Peripheric working velocity of the wheel | variable [m/s] |
Va | Velocity of water striking the wheel | variable [m/s] |
n | Number of buckets per wheel | 25 (D = 2.0) |
s | Wheel bucket surface area in cross-section | 0.045–0.05 m2 |
Qw | Discharge delivered on the wheel | variable [m3/s] |
Tc | Ratio of Nw/Nc for the wheel | 0.2–0.4 |
Tv | Ratio of Va/Vw for the wheel | 2.0–2.5 |
Tb | Mean filling ratio of buckets | 0.3–0.4 |
