A pool 50 x 20 m plan as shown in figure 1 filled with water up to h m height. To drain the water out of the pool Siphonic pumping is to
The Siphonic action works once having the piping system completely filled with water (primed completely). The valve at the end of the
pipe helps retaining the priming effect. Once the valve is opened the Siphonic action and the draining process of the pool starts. The
process continues until the whole water in the pool is drained out, assuming the suction pipe is immersed deep enough very close to the
bottom of the pool.
– Select values for the variables: z1, z2, z3, h and pipe inside diameter D of your choice.
– Friction loss in the pipe sections can be estimated using Darcy equation, hL
= f (L/D).V2
/2g, where f, is the friction factor and can be
taken equal to 0.002. Neglect losses in the elbows, the entrance, the exit and the valve. Calculate and draw the EGL and HGL.
– Demonstrate the location along the pipe where the cavitation may occurs.
– Determine the maximum flow rate possible. The maximum flow is the one corresponding to the case when the flow separation occurs
in the piping system due to cavitation effect. Calculate the minimum time needed to empty the pool.
– At the case of the maximum flow rate, calculate the reactions at the support at point A.
– Repeat your calculations for different values of pipe diameter, calculate and plot the minimum time needed to empty the pool function
of the pipe diameter, D.
– Suggest and demonstrate through calculations a method that enhances the draining process, without a need to lower the pipe end more
for one case of a pipe diameter.