PREDICTION FOR DISCHARGES OF LABYRINTH-CHANNEL EMITTERS BASED ON COMPUTATIONAL FLUID DYNAMICS

A physical model for discharges prediction of emitters is reconstructed by reversing the structures of emitter molded parts, and both laminar flow model and turbulence model are adopted to calculate the discharges of labyrinth- channel emitters under the pressure values of 40~150 kPa. Experiments are also performed to test the relationship between emitter discharges and pressure heads. The experimental results verify the feasibility of predicting discharges based on compu- tational fluid dynamics (CFD), and it is also found that turbul- ence model provides better prediction accuracy than laminar flow model does. In addition, the analyses of the flow field distribution in labyrinth channel show that the transitional Reynolds number is much lower than 2 300 due to the continuous sharp bends. At the Reynolds number 250～300, the flow transition occurs, which leads to the fact that the flow inside this emitter is turbulent under the pressures of 40～150 kPa.