Assessing the impact of flow regulators with a pressure-driven performance analysis model

In on-demand pressurized irrigation systems, discharges and pressures vary strongly in time and space throughout the network; performance analysis under different operational conditions is therefore needed. Performance analysis models usually assume a constant hydrants’ discharge and do not consider effects of installed pressure and discharge regulation devices. These aspects can be considered using the pressure-driven FLUCS model, which is described in a companion paper. Two performances indicators applied to every hydrants are use: relative pressure deficit and reliability. In the present paper, four different types of networks were analyzed considering the characteristic curves of most common hydrants and upstream flow regulators. Results show that performances highly depend upon the selected combination of flow and pressure regulators installed at the upstream end of networks and at the hydrants. When the number of operating hydrants may exceed that set at design, as it often occurs during peak demand periods, best results are obtained with upstream flow limiters that allow some flexibility in discharge regulation and produce relatively low head losses. Under these conditions, proportional discharge regulators at hydrants perform better than constant discharge hydrants.