Effects of working pressure on hydraulic performances of labyrinth path emitters

To decrease working pressure of drip irrigation emitter may become an efficient way of decreasing energy consumption and operating cost, but there are few emitters working under low pressure at present. Based on this, the products of 5 typical widely-used labyrinth path emitters were studied in the paper. The effects of different working pressures on hydraulic performances and energy dissipation characteristics of emitters were analyzed. The results showed that low pressure had some effect on flux coefficient and flow regime index, but the effect on flow regime index was insignificant. Flux coefficient of the same structure had prominent linear correlation with A/L2, which is a dimensionless number. However, flux coefficients of different flow paths had varied wildly. The flow states of 5 flow paths were turbulent flow with no flow transition. It was not appropriate to determine the flow state of flow path by critical Reynolds number which is 2 200 in general.