关键词: 空化, 喷嘴长度, 射流式施肥器, 吸肥性能

Abstract: In order to strengthen the injection performance of the fertilizer injector, computational fluid dynamics (CFD) was used to study the effect of nozzle length on the performance of the jet fertilizer injector. An incompressible multiphase flow model was established to examine the impact of nozzle length on the injection performance of the jet fertilizer injector and investigate its influencing mechanisms. The results showed that the nozzle length has a significant effect on the injection performance of the jet fertilizer injector. When the nozzle length was too long, the growth of fertilizer absorption was limited, reducing the fertilizer injection performance. Under different inlet and outlet pressures, the fertilizer absorption concentration, inlet flow ratio, and fertilizer absorption efficiency of the fertilizer injector were all at their lowest when the nozzle length was L. When the inlet and outlet pressure differed by 1.0 MPa, the fertilizer absorption of the fertilizer applicator with a shorter nozzle length was more than 10% larger than that of the fertilizer injector with a nozzle length of L. Through analyzing the internal flow field of the fertilizer injector, it was found that the negative pressure distribution inside the fertilizer injector is a key factor affecting the injection performance. Longer nozzle lengths limit the negative pressure distribution area inside the fertilizer absorption chamber and lead to more intense cavitation, thus affecting its corresponding injection performance. This study provides theoretical support for the design and optimization of jet fertilizer injectors.

Key words: cavitation, nozzle length, jet fertilizer injector, injection performance