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| Minhoni,Renata T. de A.; Pereira,Francisca F. S.; Silva,Tatiane B. G. da; Castro,Evanize R.; Saad,João C. C.. |
| ABSTRACT The Darcy-Weisbach equation is the most recommended equation for determining the pressure loss in pressurized pipes because of its wide applicability. However, one of the largest obstacles to implementing this equation is the friction factor (f) calculation. This factor can be precisely determined using the Colebrook equation, which is implicit. Thus, the objective of this study was to compare six explicit equations for calculating the Darcy-Weisbach friction factor with the implicit Colebrook equation based on the relative error. Based on the results, the equations of Vatankhah and Offor & Alabi were the most highly recommended. These six explicit formulas showed a mean relative error of less than ± 1% compared to the Colebrook equation,... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Absolute roughness; Colebrook equation; Forced conduits; Head loss; Hydraulic load; Reynolds number. |
| Ano: 2020 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-69162020000200258 |
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| Pimenta,Bruna D.; Robaina,Adroaldo D.; Peiter,Marcia X.; Mezzomo,Wellington; Kirchner,Jardel H.; Ben,Luis H. B.. |
| ABSTRACT One of the parameters involved in the design of pressurized hydraulic systems is the pressure drop in the pipes. The verification of the pressure drop can be performed through the Darcy-Weisbach formulation, which considers a coefficient of head loss (f) that can be estimated by the implicit Colebrook-White equation. However, for this determination, it is necessary to use numerical methods or the Moody diagram. Because of this, numerous explicit approaches have been proposed to overcome such limitation. In this sense, the objective of this study was to analyze the explicit approximations of the f for pressurized conduits in comparison to the Colebrook-White formulation, determining the most precise ones so that they can be used as an alternative... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Head loss; Darcy-Weisbach; Turbulent flow regime; Performance index. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662018000500301 |
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| Rocha,Hermes S. da; Marques,Patricia A. A.; Camargo,Antonio P. de; Frizzone,José A.; Saretta,Ezequiel. |
| ABSTRACT Assuming that a roughness meter can be successfully employed to measure the roughness on the internal surface of irrigation pipes, this research had the purpose of defining parameters and procedures required to represent the internal surface roughness of plastic pipes used in irrigation. In 2013, the roughness parameter Ra, traditional for the representation of surface irregularities in most situations, and the parameters Rc, Rq, and Ry were estimated based on 350 samples of polyvinyl chloride (PVC) and low-density polyethylene (LDPE) pipes. Pressure losses were determined from experiments carried out in laboratory. Estimations of pressure loss varied significantly according to the roughness parameters (Ra, Rc, Rq, and Ry) and the corresponding... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Friction factor; Head loss; Roughness meter. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-43662017000300143 |
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