On Oct 29, 2012 Hurrcane Sandy
Flooded the Holland Tunnel that passes
Under the Hudson River!
The Tunnel has two tubes:
One is 8558 feet long
And the other is 8371 feet long
Both are 12.5 feet high by 20 feet wide!
=> (8558 + 8371)*20*12.5 = 4,232,250 Cubic Feet of Water
Let's assume you want to pump this water out in 72 hours (or 3 days).
If your pumps have six inch diameter pipes and can
Pump at a pressure of 50 psi,
How many pumps will you need to empty these
Tunnels in 72 hours?
The Volume of water for a 6 inch pipe at 50 psi
=> 16.872982 Cubic Feet per Second
Where P = Pressure = psi
And D = Pipe Diameter in feet = 1/2 foot
Water Speed = V = Sq-Rt(2*g*h)
Where g = 32 ft/s/s and h = feet depth
=> V = 8*(Sq-Rt(h)) since 2*g = 64
And Water Pressure k = 62.4/144 psi per foot depth
=> If P = 50 psi => Convert psi to Height of Water Column that results in 50 psi
=> (144/62.4)*50 = Height of Water Column to Create 50 psi => h = 115.38 Feet
Area of Pipe = (((Pi)*D*D)/4) And V = 8*(Sq-Rt(h)) = Speed
Equals the flow rate = Cubic-Feet per Second
=> 9.5448*D*D*(Sq-Rt(P)) Cubic-Feet per Second
Water emerges from a fire hose
at 64 ft/sec. If the rate of
the flow is 180 gallons/minute, find the horse power of the
pump motor if the efficiency of the pump is 50%.
Also, find the force to hold the fire hose.