Performance Test of Venturi Aerators for Subsurface Drip Irrigation

Abstract

Subsurface drip irrigation systems with water and fertilizer-aerated irrigation technology have helped improve crop yield and quality and are receiving increasing attention in the field of agricultural efficient irrigation. Venturi is an important part of water and fertilizer-aerated irrigation technology as a subsurface drip aeration device, but its performance is yet unknown. Consequently, to explore the working performance of the Venturi applicator as a subsurface drip aeration device, three different structures of DN20 Venturi applicators were selected, and the suction characteristics, working parameters, and stability of the Venturi aerators at five inlet pressure levels were measured according to a certain outlet pressure gradient. The results indicated that the gas injection flow of different Venturi aerators fluctuate in the form of peak–valley quasi periodic motion, and the fluctuation range is 20–300 L/h; under different inlet pressure levels, the average gas injection flows of the three Venturi aerators increase with the pressure difference, and the maximum average gas injection flow of the type plasson (PL) and type netafim (NF) types remains generally stable with the increase in inlet pressure. Furthermore, the standard deviation of gas injection flow is consistent with the gas injection flow. Under the same working condition, the type mazzei (MZ)-type Venturi device has the advantages of low working pressure range, large working flow, and high stability compared with PL and NF types, and thus it is suitable for use as the gas-filling equipment of subsurface drip irrigation systems. Furthermore, a suction estimation model related to the working inlet and outlet pressure is constructed, and the suction capacity can be estimated according to the inlet and outlet pressures of the Venturi aerator. The study findings can provide a reference for engineering application selection and help to improve the performance of Venturi.