Macroscopic Analysis of Pressure Loss Coefficient in Pipes and Ducts (2nd Report, Loss Coefficient of Miter Bends)

Abstract

For the famous formulas of pipes and ducts, for example, Weisbach's formulas of the pressure loss coefficients in entrance flush with wall at arbitrary angle, abrupt contraction, miter bend, and so on, it is still not clear whether some of these formulas could be derived from a simple flow model or not. In this paper, analysis was conducted by using linear momentum theorem for these equations from to the macroscopic point of view. It was found that these formulas could be derived as modified equations of the equations obtained by using the momentum theorem. In the second report, the pressure loss coefficient of miter bends (elbows) and the effect of inner rounded corner (r/D) were examined.