The above screen is partially clogged. The maximum head loss that is allowed in the screen channel is 0.2 m. For the calculation: take the impact of clogging on the friction coefficient into account. The friction coefficient (C) for a clogged screen is 0.6.
Calculate the maximum clogging allowed before the screen needs to be cleaned.
To calculate the maximum clogging allowed before the screen needs to be cleaned, we need to consider the impact of clogging on the friction coefficient.
The formula to calculate the head loss (H) due to friction in a screen channel is:
H = (f * L * V^2) / (2 * g * D)
Where:
H = Head loss (m)
f = Friction coefficient
L = Length of the screen channel (m)
V = Velocity of flow (m/s)
g = Acceleration due to gravity (9.81 m/s^2)
D = Hydraulic diameter (m)
In this case, the maximum head loss allowed is 0.2 m. We can rearrange the formula to solve for the maximum clogging, which is the maximum allowable change in the friction coefficient (C) before the head loss exceeds the limit:
C = (2 * H * g * D) / (L * V^2)
We are given that the friction coefficient (C) for a clogged screen is 0.6. Therefore, to find the maximum clogging allowed, we can substitute the given values into the formula and solve for H:
0.6 = (2 * 0.2 * 9.81 * D) / (L * V^2)
Now, to get the maximum clogging allowed, we can rearrange the formula:
H = (C * L * V^2) / (2 * g * D)
Substituting the given values:
H = (0.6 * L * V^2) / (2 * 9.81 * D)
This will give you the maximum clogging allowed before the screen needs to be cleaned.