Pressure loss mechanism analysed with pipe turbulence theory and friction coefficient prediction in labyrinth path of drip irrigation emitter

A labyrinth path is the predominant pattern for drip irrigation emitters at present. It is very important to explore the pressure loss mechanism for the labyrinth path. This paper took the Minkowski fractal curve flow path, a special labyrinth flow path, as an object to study the pressure loss mechanism of fractal flow paths with dimension analysis technology and rough pipe turbulence theory. The results of the research showed that the Reynolds number has an insignificant effect on the friction coefficient of the flow path, which can be ignored. The friction coefficient was primarily related to the hydraulic radius, fractal dimension and unit length of the fractal flow path. Under the pressure of 15-150 kpa within the fractal flow path, the flow was completely turbulent. Hence, constructing the fractal flow path is an effective approach to simultaneously enhancing the hydraulic performance and anti-clogging performance. The critical Reynolds number for flow twist was moved earlier because of the continuous disturbance within the flow path of the emitters. Copyright © 2010 John Wiley & Sons, Ltd.