Purpose

In plethora of petroleum, chemical and heat transfer applications, T-junction is often used to partially separate gas from other fluids, to reduce work burden on other separating equipment. The abundance of liquid carryovers from the T-junction side arm is the cause of production downtime in terms of frequent tripping of downstream equipment train. Literature review revealed that regular and reduced T-junctions either have high peak liquid carryovers (PLCs) or the liquid appears early in the side arm [liquid carryover threshold (LCT)]. The purpose of this study is to harvest the useful features of regular and reduced T-junction and analyze diverging T-junction having upstream and downstream pipes.

Design/methodology/approach

Volume of fluid as a multiphase model, available in ANSYS Fluent, was used to simulate air–water slug flow in five diverging T-junctions for eight distinct velocity ratios. PLCs and LCT were chosen as key performance indices.

Findings

The results indicated that T (0.5–1) and (0.8–1) performed better as low liquid carryovers and high LCT were achieved having separation efficiencies of 96% and 94.5%, respectively. These two diverging T-junctions had significantly lower PLCs and high LCT when compared to other three T-junctions. Results showed that the sudden reduction in the side arm diameter results in high liquid carryovers and lower LCT. Low water and air superficial velocities tend to have low PLC and high LCT.

Research limitations/implications

This study involved working fluids air and water but applies to other types of fluids as well.

Practical implications

The novel T-junction design introduced in this study has significantly higher LCT and lower PLC. This is an indication of higher phase separation performance as compared to other types of T-junctions. Because of lower liquid take-offs, there will be less frequent downstream equipment tripping resulting in lower maintenance costs. Empirical correlations presented in this study can predict fraction of gas and liquid in the side arm without having to repeat the experiment.

Social implications

Maintenance costs and production downtime can be significantly reduced with the implication of diverging T-junction design.

Originality/value

The presented study revealed that the diameter ratio has a significant impact on PLC and LCT. It can be concluded that novel T-junction designs, T2 and T3, achieved high phase separation; therefore, it is favorable to use in the industry. Furthermore, a few limitations in terms of diameter ratio are also discussed in detail.

中文翻译：

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发散 T 型接头相分离的数值研究和预测

目的

在众多的石油、化工和传热应用中，T 型接头通常用于将气体与其他流体部分分离，以减轻其他分离设备的工作负担。T 型接头侧臂中大量残留的液体是下游设备链频繁跳闸导致生产停工的原因。文献回顾显示，常规和减少的 T 型接头要么具有高峰值液体携带 (PLC)，要么液体在侧臂中出现较早 [液体携带阈值 (LCT)]。本研究的目的是收集常规和简化 T 型接头的有用特征，并分析具有上游和下游管道的分流 T 型接头。

设计/方法/途径

ANSYS Fluent 中可用的流体体积作为多相模型，用于模拟五个不同 T 形接头中的空气-水弹流，具有八个不同的速度比。选择 PLC 和 LCT 作为关键性能指标。

发现

结果表明，T (0.5–1) 和 (0.8–1) 表现更好，因为实现了低液体残留和高 LCT，分离效率分别为 96% 和 94.5%。与其他三个 T 型接头相比，这两个不同的 T 型接头具有显着较低的 PLC 和较高的 LCT。结果表明，侧臂直径的突然减小导致高液体残留和较低的 LCT。低水和空气表面速度往往具有低 PLC 和高 LCT。

研究局限性/影响

这项研究涉及工作流体空气和水，但也适用于其他类型的流体。

实际影响

本研究中引入的新型 T 型接头设计具有明显更高的 LCT 和更低的 PLC。与其他类型的 T 型接头相比，这表明相分离性能更高。由于液体排放量较低，下游设备跳闸的频率会降低，从而降低维护成本。本研究中提出的经验相关性可以预测侧臂中的气体和液体比例，而无需重复实验。

社会影响

分流 T 型接头设计的含义可以显着减少维护成本和生产停机时间。

原创性/价值

提出的研究表明，直径比对 PLC 和 LCT 有显着影响。可以得出结论，新型 T 型接头设计 T2 和 T3 实现了高相分离；因此，在工业上使用是有利的。此外，还详细讨论了直径比方面的一些限制。