In bubble columns (BCs), the reliable identification of the first transition velocity U_trans-1, marking the end of the homogeneous regime, is an essential prerequisite for the successful BC design since this parameter marks the onset of bubble coalescence. In this work, a new database with 13 experimental U_trans-1 values at various operating conditions is reported. They are identified precisely by different sophisticated methods, which are considered most suitable and powerful for the analysis of the specific experimental data used. The BCs have different column diameters (and bed aspect ratios) and they are equipped with different perforated plate (PP) gas distributors. For U_trans-1 identification, eight different time-dependent signals recorded in air-deionized water, air-tap water, nitrogen-tap water, nitrogen-ethanol (96%), air-therminol and air-benzonitrile systems have been analyzed. The hidden information in the time series has been quantified by reliable identification parameters such as degree of randomness of the signal, Kolmogorov, information and reconstruction entropies and degree of disorder of the signal. Their profiles as a function of superficial gas velocity have been used for flow regime identification.

In the case of column diameters between 0.1 m and 0.46 m and bed aspect ratios beyond 5, a simple empirical rule-of-thumb has been established: when the open area (OA) of the PP gas distributors is ≤1.0%, the U_trans-1 value should occur at around 0.03 m/s. On the other hand, when the OA is greater than 1.0%, then the U_trans-1 value is identifiable at 0.04 m/s. It has been found that this new rule yields better predictions than the most popular empirical correlation of Reilly et al. (1994).

在气泡塔（BC）中，可靠地识别第一过渡速度U _trans-1（标记均质状态的终点）是成功进行BC设计的必要先决条件，因为该参数标志着气泡聚结的开始。在这项工作中，报告了一个在不同操作条件下具有13个实验U _trans-1值的新数据库。它们可以通过不同的复杂方法进行精确识别，这些方法被认为是分析所用特定实验数据最合适，最有效的方法。BC具有不同的色谱柱直径（和床长宽比），并且配备有不同的多孔板（PP）气体分配器。对于U _trans-1鉴定中，分析了空气去离子水，空气自来水，氮气自来水，氮气-乙醇（96％），空气-氨酚和空气-苄腈系统中记录的八个不同的随时间变化的信号。时间序列中的隐藏信息已通过可靠的识别参数进行了量化，例如信号的随机度，Kolmogorov，信息和重构熵以及信号的无序度。它们的曲线作为表观气体速度的函数已被用于流态识别。

如果色谱柱直径在0.1 m和0.46 m之间，并且床的宽高比超过5，则建立了简单的经验经验法则：当PP气体分配器的开放面积（OA）≤1.0％时，U _trans-1值应在0.03 m / s左右发生。另一方面，当OA大于1.0％时，则可以确定U _trans-1值为0.04 m / s。已经发现，与Reilly等人的最流行的经验相关性相比，该新规则产生了更好的预测。（1994）。