Transient gas–liquid two-phase flows are often encountered in nuclear industries. Investigating the dynamics of the transient gas–liquid flows is of significance for optimizing the reaction processes and predicting the thermal–hydraulic phenomena relevant to the performance of nuclear reactors. In this study, a multi-nozzle gas inlet was designed to mimic the transient gas–liquid flows in a horizontal pipe. A conductance wire-mesh sensor (WMS) was used to visualize the phase distribution at the pipe cross-section. Based on the WMS data, a cost-based recurrence analysis (CBRP) was developed to reveal the dynamics of transient gas–liquid flows. Different transition processes from plug flow to slug flow were observed in the experiment and explored by the determinism (DET) of the CBRP. Note that special flow structures, i.e., wave bridge and pseudo slug, were encountered during the flow pattern transition, and their generation mechanisms were uncovered. The processes of the flow pattern transition were also characterized by the slug frequency and the probability density function of the water holdup, which presented a good agreement with the CBRP results.

核工业中经常会遇到瞬态气液两相流。研究瞬态气液流动的动力学对于优化反应过程和预测与核反应堆性能有关的热工现象具有重要意义。在这项研究中，设计了多喷嘴进气口来模拟水平管中的瞬态气液流动。电导金属丝网传感器（WMS）用于可视化管道横截面处的相分布。基于WMS数据，开发了基于成本的重复分析（CBRP），以揭示瞬态气液流动的动力学。在实验中观察到了从塞流到团状流的不同过渡过程，并通过确定性（DET）。请注意，在流型转换过程中会遇到特殊的流动结构，例如波桥和拟，并揭示了它们的生成机理。流段过渡过程的特征还在于段塞频率和持水率的概率密度函数，与CBRP结果吻合良好。