Influence of elastic diaphragm on hydraulic performance of pipe-type pressure compensating emitter and simulation of internal fluid structure interaction
XU Yao, SU Yanping, YANG Peiling*, REN Shumei
College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China
Abstract：In order to study the influence of elastic diaphragm parameters on the hydraulic performance of pipe-type pressure compensating emitter and the internal compensating principle of compensation pressure chamber, the pressure compensating emitter of type supertif-03120-0003 is used as the prototype and a pipe-type emitter experimental model is fabricated with 3D printing. The pressure-flow curve of the model was measured at inlet pressures ranged in 0-350 kPa. The effects of thickness and hardness of the natural rubber elastic diaphragm on the hydraulic performance of the emitter were analyzed. A fluid-structure interaction(FSI)analysis on the compensating principle and hydraulic performance in the emitter was launched in ADINA software. The results showed that when the thickness of the elastic diaphragm was constant, the discharge flow and compensating threshold pressure of the emitter all increased with increase of the elastic diaphragm hardness. When the hardness was fixed, the discharge flow and compensating threshold pressure both showed an increasing trend with increase of the thickness. The growth rate of the emitter discharge flow was decreased beyond a threshold pressure, and finally the pressure-flow relationship curve tended to be flat. For this internal structure of the emitter, the elastic diaphragm was subject to an optimal combination of hardness and thickness, namely thickness 1.4 mm, hardness 50HA. The predicted pressure-flow curve was in good agreement with the measured value, and the maximum deviation between them was less than 5%, indicating that ADINA software was proper in FSI analysis of compensating principle and hydraulic performance for the emitter. This method has provided a visualization way for research and development of emitters with pressure compensation.
