CE 704 · Chapter 6
Hydropower Engineering past question
6.3 Penstocks and Pressure shaft: importance, conditions of their application, general arrangement, hydraulic transients (water hammer), Computation of hydrodynamic pressure, sizing of penstock/pressure shaft and estimation of thickness of steel in penstock/pressure shaft
A penstock carries 8 m³/s of water at head of 25m. The cost of pipe line in place is given by US$250hd² per meter length, where h=head and d=diameter of the pipe. Annual fixed charges are 8% of the pipe line cost. The estimated head loss in friction is 0.025Q²/12.1d⁵ per m length of the pipe. Efficiency of the turbine is 80% and selling price of the power is US$500 per kW per annum. Calculate the most economic diameter of the penstock. [8]