The gas-liquid cylindrical cyclone (GLCC) is a device used to separate gas from liquid in offshore or subsea oil and gas production systems. The liquid film swirling along the upper cylinder wall in the GLCC is referred to as “upper swirling liquid film” (USLF). The flow patterns of USLF have a great influence on GLCC’s separation performance. However, the dynamics of the gas-liquid flow in a GLCC, especially the USLF characteristics, have not been well understood. In this study, experiments were conducted to investigate flow characteristics of USLF in a GLCC. The range of gas and liquid Reynolds numbers, Re_g and Re_l, was 27,869 ≤ Re_g ≤ 68,120 and 2,881 ≤ Re_l ≤ 14,335 respectively. The USLF’s thickness was measured using button electrodes. The results showed that the liquid film became thinner after leaving the inlet and the circumferential fluctuation of the thickness was not significant. The gas-liquid velocities had significant influences on film thickness, which increased almost linearly as liquid velocity increased, while presented a roughly S-shaped distribution as gas velocity increased. The friction factors of GLCC were determined based on the measured liquid film thickness and pressure drop. Additionally, the USLF’s flow patterns include swirling annular flow and swirling churn flow. Finally, a judgment criterion for flow pattern transition was established under the minimum gas-liquid interfacial stress theory. The model could accurately predict the transition condition. This work may provide a basis for comprehensive understanding of USLF characteristics.

气液圆柱旋风分离器（GLCC）是一种用于在海上或海底油气生产系统中将气体与液体分离的装置。沿着GLCC中的上气缸壁旋转的液膜被称为“上部旋转液膜”（USLF）。USLF的流型对GLCC的分离性能有很大影响。然而，还没有很好地理解GLCC中气液流动的动力学，特别是USLF特性。在这项研究中，进行了实验以调查在GLCC中USLF的流动特性。气体和液体的雷诺数，范围重新_克和重新_升，为27869≤ 重新_克 ≤68120和2881≤ 重新_升 分别≤14335。USLF的厚度是使用纽扣电极测量的。结果表明，液膜离开入口后变薄，厚度的周向波动不明显。气液速度对膜厚有显着影响，膜厚随液速的增加几乎呈线性增加，而随气速的增加呈大致S形分布。GLCC的摩擦系数是根据测得的液膜厚度和压降确定的。另外，USLF的流动模式包括涡旋环形流和涡旋搅动流。最后，根据最小气液界面应力理论建立了流型转变的判断标准。该模型可以准确预测过渡条件。