The liquid stream from an orifice typically undergoes a transition process from dripping to jetting under increased pressure. The dripping–jetting (D–J) transition performance from a thin-walled tube or an orifice with a wide diameter has been well studied, where the triple contact line of the stream is pinned on the edge of the orifice and the flow behaviors are analyzed accordingly with a precondition of the fixed contact line. The D–J transition of the liquid stream from plate-type micro-orifices was investigated in our study of droplet generation for extreme ultraviolet source and wafer cleaning. The triple contact line of the stream keeps moving as pressure changes as a result of the liquid wetting and dewetting around the micro-orifice. The transition from dripping to jetting involves three processes: wetting to generate pendant droplet and dripping, jetting from pendant droplet, and pendant droplet dewetting to form jetting directly. The aforementioned performance is different from boundary-pinned conditions. To reveal the transition characteristic, critical pressure causing the D–J transition under different wetting conditions was determined. The process of wetting to generate pendant droplet and dripping, and the effects of the contact angle and the pressure difference were formulated. Analysis of the mechanism causing jetting from the pendant droplet was implemented by combining a model formulating the jet ejecting outside the droplet and numerical simulation of the stream inside the pendant droplet. Finally, the normalized model was built to illustrate the critical pressure of D–J transition concerning the triple contact line diameter.

来自孔的液体流通常在增加的压力下经历从滴落到喷射的过渡过程。对薄壁管或大直径孔口的滴水-喷射（D–J）过渡性能进行了很好的研究，流的三重接触线固定在孔口的边缘，流动特性为在固定接触线的前提下进行了相应的分析。在我们研究极端紫外线源和晶片清洁的液滴产生的研究中，研究了板式微孔的液流的D–J跃迁。由于液体在微孔周围的润湿和去润湿，流的三重接触线随着压力变化而保持移动。从滴水到喷射的过渡涉及三个过程：润湿以产生悬垂液滴并滴落，从悬垂液滴中喷出，然后悬垂液滴去湿以直接形成喷射。前述性能与边界固定条件不同。为了揭示转变特性，确定了在不同润湿条件下引起D–J转变的临界压力。阐述了润湿产生悬滴和滴落的过程，以及接触角和压差的影响。通过将形成液滴外喷射流的模型与对液滴内液滴流的数值模拟相结合的模型，对引起悬垂液滴喷射的机理进行了分析。最后，建立归一化模型来说明涉及三重接触线直径的D–J跃迁的临界压力。