Journal of electricity, power, and gas . flow in water conduits is that of Chezy, V = C \/sr (39) where C is a factor depending on roughness, r is thehydraulic mean radius (38) and s the slope. The velocityand therefore the quantity carried bya given pipewouldvary as Vs. In the case of a pipe for power devel-opment s •= f and we may say that Q is proportionalto \/f. The water quantity Q flowing in a given pipeline may then be represented by a curve of square rootswhere (Fig. 38) the ordinates are the effective heads(H—f) =h and the abscissas are the resulting waterquantities. For the purposes
Journal of electricity, power, and gas . flow in water conduits is that of Chezy, V = C \/sr (39) where C is a factor depending on roughness, r is thehydraulic mean radius (38) and s the slope. The velocityand therefore the quantity carried bya given pipewouldvary as Vs. In the case of a pipe for power devel-opment s •= f and we may say that Q is proportionalto \/f. The water quantity Q flowing in a given pipeline may then be represented by a curve of square rootswhere (Fig. 38) the ordinates are the effective heads(H—f) =h and the abscissas are the resulting waterquantities. For the purposes of demonstration thevalues are given on each line, and Table VII is givento make clear the calculation by which the curveof efficiency output is obtained. This curve indicatesthe theoretical energy contained in the dischargedwater based on different sized outlets being used withtheir corresponding resulting losses in the pipe takeninto account. The area of the inscribed rectangle D E B C willbe a measure of the energy in the Fig. 38. If the friction loss f = G C the effective head =BC = h the water quantity B E = Q; the total headG B = H. It will then be seen that when h is coincides with G and EB = Q = O. When Q is max. E coincides with F and BC = Oand GC = GB = f. Now the energy is proportional tothe area BCDE and this area is greatest when GC = 354 JOURNAL OF ELECTRICITY, POWER AND GAS [Vol. XXXII_No. 17 CB or the greatest energy is obtained when 1/3 of 2 the head is expended in friction. This is howeververy seldom the most economical point at which towork the pipe line. To sacrifice 1/3 of the energy re-coverable from any water fall for the purpose of aslight saving in the first cost of the pipe is a graveerror. For example, if a pipe line would cost $10,000delivered at the power site and develop 10,000 per cent loss, it would be better to designthe pipe for only 5 per cent loss and we may thenobtain 10,000 + per cent or 2830 additi
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