Research on the compensation mechanism of pressure compensating emitters based on numerical simulation and visualisation experiment

Abstract

Pressure compensating (PC) emitters can maintain a stable flow rate within a large pressure range, which can better meet the needs of efficient water-saving irrigation technology. The basis for designing high-performance PC emitters is clarifying their working principles. Numerical simulation and visualisation experiments were combined to study the compensation mechanism of PC emitters. Based on the visualisation experimental sample, a simulation model of a PC emitter was established for fluid–solid coupling calculation of its working process. The correctness of the numerical simulation was verified through hydraulic performance experiments and elastic diaphragm deformation visualisation experiments. A detailed analysis was conducted on the pressure drop characteristics, fluid velocity variation characteristics, elastic diaphragm deformation characteristics, and fluid-structure interaction characteristics of the PC emitter. A constant flow rate state model of the PC emitter was established. The maximum error between the numerical simulation results and the experimental results did not exceed 12 %. The results indicate that only when the energy consumption of the labyrinth channel remained constant and the energy consumption of the PC chamber increased linearly with the working pressure, could the flow rate of the PC emitters remain constant. The energy consumption capacity of the PC chamber determines when the energy consumption of the labyrinth channel changes from an increasing state to a stable state. The factors that determine the deformation characteristics of the elastic diaphragm affect the performance of the PC emitter.