微灌用文丘里施肥器综合性能试验研究

基于文丘里施肥器综合工作性能指标测试研究,以期获得文丘里施肥器结构优化设计建议.研究选用规格为DN 20的6种不同材质的国内外文丘里施肥器,基于不同进口压力和进出口压差条件,系统针对文丘里施肥器在压力能耗、吸肥效率以及振动与空化等综合性能指标开展了测试研究.结果表明:文丘里施肥器吸肥临界压差与进口压力存在显著的线性正相关;相同进口压力下,国内文丘里施肥器最大吸肥量普遍明显低于国外同类产品,且振动与空化现象受压差变化敏感性较强;同一模具下,收缩率较小材质的施肥器制造偏差小,吸肥性能好, UPVC可作为生产施肥器的优选原料之一;此外,文丘里施肥器存在与其内部结构相对应的吸肥量上限,压差增大后导致振动与空化现象的加强是抑制文丘里施肥器吸肥能力进一步提升的重要原因.

Experimental study on comprehensive working performance of Venturi injector

In order to obtain some suggestions for optimal structure design of Venturi injector, some comprehensive indicators of working performance for Venturi injector were evaluated. Based on diffe-rent inlet pressure and pressure differences between inlet and outlet conditions, six DN 20 Venturi injectors of different materials were systematically studied for pressure loss, efficiency in absorbing fertili-zer, cavitation-vibration and so on. The results showed that critical pressure difference has an ob-viously positive correlation with inlet pressure. With the same inlet pressure, the maximum rate of flow in absorbing fertilizer for homemade Venturi injector is less than that for the foreign same product universally, and the cavitation and vibration of homemade Venturi injector are sensitive to the variation of pressure. For the same mold size, the material with low mold shrinkage performance has smaller manufacturing error, and its suction performance is better. UPVC could be recommended as one of the pro-per raw materials for the manufacture of Venturi injector. In addition, each Venturi injector has the theoretic upper limit of the suction amount corresponding with its internal structure parameters. The cavitation was strengthened with pressure difference increasing, which was one of the important reasons for the not further improving of the efficiency in absorbing fertilizer.