Effect of compensation chamber structure on the hydraulic performance of pressure compensating drip emitters

Abstract

Pressure compensating (PC) emitters are installed at the end of the drip irrigation system to compensate for pressure loss and deliver water evenly to each crop. The PC emitter with excellent hydraulic performance can improve the irrigation uniformity of drip irrigation system. In this paper, the effects of main structural parameters of compensation chamber on the hydraulic performance of PC emitters were investigated by response surface methodology, and multivariate regression models were built to obtain the best hydraulic performance. The results showed that the minimum compensating pressure of PC emitters increased with the increase of compensation chamber height, while it decreased with the increase of compensation chamber diameter. The flow fluctuation exponent of PC emitters was affected by all the four structural parameters, which were outflow groove depth, outflow groove width, compensation chamber height and compensation chamber diameter. The outflow groove depth had the greatest influence on flow fluctuation exponent, and with the increase of outflow groove depth, the flow fluctuation exponent first decreased and then increased. Moreover, the value of the outflow groove depth influenced the effect of the other three parameters on flow fluctuation exponent. The optimal combination of parameters was: outflow groove depth of 0.14 mm, outflow groove width of 0.37 mm, compensation chamber height of 0.83 mm and compensation chamber diameter of 6.91 mm. The corresponding optimal results were: minimum compensating pressure of 38.73 kPa and flow fluctuation exponent of 0.024. The research provides a reference for the design and optimisation of PC emitters. • Interactions between parameters studied by response surface methodology. • Optimization goal was to reduce minimum compensating pressure and flow fluctuation of PC emitters. • Compensation chamber height and diameter had the opposite effect on performance index. • Overflow groove depth was the most important parameter affecting the flow fluctuation of PC emitters.