电流体喷印相邻喷嘴射流干扰机理与抑制探讨

Discussion on mechanism and suppression of jet interference from adjacent nozzles in electrohydrodynamic jet printing

针对多喷嘴式电流体喷印系统中相邻喷嘴之间的带电射流干扰问题,建立电液耦合作用下的射流喷射的数值仿真模型。采用控制变量法揭示了相邻喷嘴锥射流产生干扰的原因及工作电压、供液流量和相邻间距对于射流干扰程度的影响规律。初步探讨了一种基于环形气流辅助喷射的射流干扰抑制方法,建立了气—电—液多场耦合作用下的射流喷射的数值仿真模型。通过研究不同气流速度对于射流喷射的影响规律,结果表明:射流偏斜角随着电极电压的增大而增大,随喷嘴间距的增大而减小,随溶液流量的改变不明显。在合理的工艺条件下,射流能够垂直喷射到基底上。适当的辅助气流输入(5~25m/s)可有效抑制喷嘴锥射流因电致斥力产生的干扰。当气流速度超过临界阈值(25m/s)后,辅助气流对喷嘴锥射流容易带来额外的不稳定性和不可控性。

Aiming at the problem of charged jet interference between adjacent nozzles in the multi-nozzle electrohydrodynamic jet printing system,a numerical simulation model of jet ejection under electro-hydraulic coupling is established.The control variable method is used to reveal the reason for the interference of adjacent nozzle cones jet and the influence law of working voltage,liquid supply flow and adjacent distance on the degree of jet interference.Furthermore,a jet interference suppression method based on annular airflow assisted injection is preliminarily discussed.A numerical simulation model of jet injection under the coupling action of gas-electricity-hydraulic multi-field is also established.By studying the influence law of different airflow velocities on jet injection,the results show that jet deflection angle increases with the increase of the electrode voltage,decreases with the increase of the nozzle spacing,and does not change significantly with the solution flow rate.Under reasonable process conditions,the jet can be sprayed vertically onto the substrate.Appropriate auxiliary airflow input(5~25 m/s)can effectively suppress the interference of the nozzle cone jet caused by the electric repulsion force.When the airflow velocity exceeds the critical threshold(25 m/s),the auxiliary airflow will easily bring additional instability and uncontrollability to the nozzle cone jet.