Water Turbine Calculations
Posted: Sat Jun 15, 2013 2:05 am
Hey there, im having a slight issue understanding a few concepts, il explain the scenario first.
Imagine a 60 cm diameter cast iron pipe which is 100 meters long with a change of elevation of 50 meters from start to end of pipe. 100 litres per second of waste water is fed into the start of the pipe, and i want to calculate how much energy could be produced by implementing a turbine at the end.
Assuming the pipe is full of water from start to finish, what would be the best way of calculating the potential power by use of a turbine? Also how could i ensure that the pipe remained full of water, thus the 100 liters per second of water flowed through the turbine?
This is what i have been thinking as an initial calculation (not including turbine efficiency or loss of head due to friction):
Power = mgh = (100 kg/s) X (9.81 m/s2) X (50 m) = 49050 W or 49 kW
Obviously as the pipe diameter is quite large, id assume it would have to be reduced before entering the turbine. But i cannot get my head around how the flowrate within the pipe can be made to be a constant at 100 litres per second, any less and the water in the pipe will reduce, any more and the water will overflow?
The only thing i can think of is because the head and flowrate is set, the diameter at the discharge end of the pipe must be changed to suit? But im unsure how you can calculate that, and also adding the turbine would affect head loss, changing the diameter?
Any help would be greatly appreciated, im stumped right now!
Imagine a 60 cm diameter cast iron pipe which is 100 meters long with a change of elevation of 50 meters from start to end of pipe. 100 litres per second of waste water is fed into the start of the pipe, and i want to calculate how much energy could be produced by implementing a turbine at the end.
Assuming the pipe is full of water from start to finish, what would be the best way of calculating the potential power by use of a turbine? Also how could i ensure that the pipe remained full of water, thus the 100 liters per second of water flowed through the turbine?
This is what i have been thinking as an initial calculation (not including turbine efficiency or loss of head due to friction):
Power = mgh = (100 kg/s) X (9.81 m/s2) X (50 m) = 49050 W or 49 kW
Obviously as the pipe diameter is quite large, id assume it would have to be reduced before entering the turbine. But i cannot get my head around how the flowrate within the pipe can be made to be a constant at 100 litres per second, any less and the water in the pipe will reduce, any more and the water will overflow?
The only thing i can think of is because the head and flowrate is set, the diameter at the discharge end of the pipe must be changed to suit? But im unsure how you can calculate that, and also adding the turbine would affect head loss, changing the diameter?
Any help would be greatly appreciated, im stumped right now!