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Mathematical Problems in Engineering
Volume 2006, Article ID 17263, 17 pages
http://dx.doi.org/10.1155/MPE/2006/17263

Model for determining flow diameter and economic velocity in water elevating systems

1Phytosanity Department, Rural and Soil Engineering, FEIS, Universidade Estadual Paulista (UNESP), Ilha Solteira, SP 15385-000, Brazil
2Agronomy Department, FEIS, Universidade Estadual Paulista (UNESP), Ilha Solteira, SP 15385-000, Brazil
3Mathematics Department, FEIS, Universidade Estadual Paulista (UNESP), Ilha Solteira, SP 15385-000, Brazil

Received 28 September 2004; Revised 13 April 2006; Accepted 18 April 2006

Copyright © 2006 João L. Zocoler et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The purpose of this paper was to develop a model for calculating the economical flow diameter and velocity, by obtaining the economical diameter, using Swamee's friction factor equation, by minimizing the total annual cost. The application of the model to a regular supply condition showed that the diameter of the actual condition, 250 mm, compared with the diameter calculated by the mode, at the same tariff as that applied to the property (ground), 284.1 mm, involved the necessity to generate, transmit, and distribute extra electrical energy, due to the higher load loss caused by the original diameter, approximately 30800 kWh/year. This means that in one year, the consumer would spend R$2,804.00 more on pumping cost alone.