A review of the methodologies for estimating the coefficient of losses in pipe curves under turbulent flow

A review of the methodologies reported in the literature is presented to estimate the coefficient of losses in simple pipe curves and installed in series with L-shape, S, U, and Z. The information is presented organized in chronological order and homogenized for comparison, providing the coefficient according to the angle of the curve, the ratio of the radius to the internal diameter and the Reynolds number. From this analysis, a summary is displayed where characteristics and parameters considered in each methodology are contrasted, as well as the presentation of results and validity specifications. With this it has been found that different methodologies are available to obtain the loss coefficient, through which different values are obtained, which may be due mainly to inequalities in the material analyzed and, in the factors, adopted in the investigations. The most studied simple and installed series curves are of 90ºangle with gradual condition and U-shape (180º), respectively. The most suggested works to estimate the coefficient in curves are those of Kirchbach (1929) and Ito (1959, 1960), however, the Idel'chik (1966) manual presents the most extensive information for all the devices studied.