Calculate the total available energy from a water stream by use of a t

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SUMMARY

This discussion focuses on calculating the potential energy obtainable from a water stream using a turbine, specifically with a 30-meter elevation change and a flow rate of 10 liters per second. The formula presented for power generation is based on the mass flow rate, gravitational constant, and change in elevation, resulting in a theoretical power output of 2.94 kW, minus friction losses. Additionally, the user seeks clarification on calculating the Reynolds number for a partially filled pipe, suggesting the use of the velocity formula v = Q/A, where Q is the volumetric flow rate and A is the cross-sectional area of the stream.

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bobmurray1
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I keep confusing myself on this question, basically i want to know how you would determine the amount of potential energy you could capture by using a turbine, if water is flowing down a pipe into a river.

The change in elevation from the start to end of pipe is 30 meters.
The pipe is 100 meters long.
Water is flowing at a rate of 10 liters per second.

Not assuming the efficiency of the water turbine itself, is the formula just the potential energy minus the friction in the pipe? Thus:
Power per time = (Mass Flowrate X Gravitational constant X Change in Elevation) - Friction losses
= ((10 L/s X 0.001 m3/L X 1000 kg/m3) X (9.81 m/s2) X (30 m)) - Friction
= (2943 W/s or 2.94 kW/s) - Friction

Also second question, I know how to calculate the friction in a pipe, but the problem i cannot get my head around is that because the pipe is nearly a meter in diameter, the pipe is not full of water, thus i don't know how to calculate Reynolds number etc? Any help here would also be appreciated,

Thanks Guys
 
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If only you knew the velocity of the stream...

Why not try v = Q/A ; Q = volumetric flow rate, A = area of the stream, v= average velocity

See as a reference,
Open channel flow
http://mysite.du.edu/~etuttle/tech/opench.htm
 

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