微灌系统文丘里施肥器吸肥性能试验

为了研究微灌系统文丘里施肥器吸肥性能与结构参数的关系,对4种组合式喉管规格的某文丘里施肥器分别在0.10,0.15,0.20,0.25和0.30 MPa进口压力下进行了吸肥性能试验.研究结果表明,文丘里施肥器临界压差和最大压差与进口压力呈线性正相关关系,进口流量随着进口压力或进出口压差的升高而呈增大趋势;当出口与进口压力之比低于0.4时,随着喉管直径的减小、收缩角和扩散角的增大,吸肥流量与出口流量之比逐渐上升;而当压力比高于0.4时,吸肥流量与出口流量之比则呈相反的变化趋势.建立了吸肥性能与喉管几何尺寸及工作参数之间关系的回归模型,可为文丘里施肥器的设计和运行提供技术依据.

Injection performance of Venturi injector in micro-irrigation system

In order to study the relationship between the injection performance and the structural parameters of Venturi injector used in micro-irrigation system,injection performance tests of a kind of Venturi injector with four types of replaceable throat parts were conducted under inlet pressures of 0.10,0.15,0.20,0.25 and 0.30 MPa,respectively.The results show that both the critical and maximum pressure differences are in positively linear relation with the inlet pressure.The inlet flow rate of the Venturi injector increases with the increasing of the inlet pressure or the difference between inlet and outlet pressures.As the ratio of outlet pressure to inlet pressure is less than 0.4,the ratio of injection rate to outlet flow rate increases with the decrease of the throat diameter and the increase of both the contraction and diffusion angles.As the ratio of outlet pressure to inlet pressure is greater than 0.4,the ratio of injection rate to outlet flow rate changes in an opposite trend.The established regression models describing the relationship between injection performance,throat geometry and working parameters can be used for design and operation of Venturi injector.