Characterization and selection method of Venturi injectors for pressurized irrigation

ABSTRACT Venturi-type chemigation injectors are widely used due to their advantages: they do not require electric power and are cheap to operate. However, they also generate considerable energy losses which affect the pressure in the system. The correct characterization of these systems requires pressures to be correctly set at the inlet, injector and outlet points in relation to main and injected solution flows. These analytical relationships, as described in the International Organization for Standardization’s standard ISO 15873:2002, can be obtained theoretically, although it is recommended that the manufacturer should determine the real behavior of the injector by operational tests. These relationships should also be provided graphically in the form of nomograms in order to facilitate the association of the variables involved and the subsequent selection of a specific model or class and type of assembly. In order to make the right choice, it is also necessary to have precise information on the irrigation sub-units that it feeds and the grower’s fertilization program.

【摘要】文丘里式灌溉施肥注液器（Venturi-type chemigation injectors）因无需电力且运行成本低廉而获得广泛应用。不过，这类注液器会产生可观的能量损失，进而对系统内的压力产生影响。对这类系统进行准确的特性表征，需要结合主溶液流与注入溶液流的工况，正确设定入口、注液器本体及出口测点处的压力。国际标准化组织（International Organization for Standardization，ISO）标准ISO 15873:2002中所述的解析关系式，可通过理论推导得到，但建议制造商通过运行试验确定注液器的实际运行特性。为便于相关变量的关联分析以及后续特定型号、类别与装配形式的选型，这类解析关系式还应以列线图（nomograms）的形式进行可视化呈现。若要做出合理的选型决策，还需掌握其所供水的灌溉子单元以及种植者施肥方案的精准信息。