## 3 Experimental Setup and Observations  
### Multiphase Flow Laboratory  
The data set used to train the network for feature fusion to identify flow patterns was provided by the subsea multiphase flow experimental platform at Dalian Maritime University. The modification design of an M-shaped rigid jumper with a pipe with an inner diameter of 50 mm served as the foundation for the experimental platform in the multiphase flow laboratory, and the pipe was constructed of stainless steel 304. The flow pattern information of two-phase flow was collected experimentally, and during the experiment, the fluids that flow in the tube were tap water and air. Figure 9 displays the piping diagram for the gas-water two-phase flow test, Figure 10 indicates the size of the pipeline in the experimental section and the direction of the two-phase flow into the pipeline. The specific dimensions of the jumper are shown in Table 1. The nominal diameter of the pipe is 50 mm, the inner diameter is 48 mm, and the wall thickness is 6 mm. Figure 8: Confusion matrix. The multiphase flow experimental circuit mainly consists of a three-phase separator, two vertical multi-stage centrifugal pumps, flow control valves, air compressors, air bottles, lyophilizer, mixing pipelines, and M-type cross-connections. At the same time, pressure and temperature sensors were installed in each part of the pipeline and test section to monitor the experimental conditions. In the experiment, the medium used for the gas phase was compressed air (density is 1.29 kg/m\({}^{3}\), dynamic viscosity is 17.9 \(\times\) 10\({}^{-6}\) Pa-s). An air compressor with a maximum 20 bar exhaust pressure was available in the lab. After being pressurized by the air compressor, the air enters the air bottle and is transported to the freeze-dryer for drying and processing to reduce the air temperature and prevent its negative impact. Before the compressed air enters the gas-liquid mixing section, the system measures the gas flow rate through the gas mass flow meter. It transmits it back to the control system of the laboratory bench, through which the control system can adjust the gas flow valve to control the gas flow rate. At the same time, the pipeline is also set up with a pneumatic shut-off valve to prevent gas leakage into the pipeline. The medium used for the liquid phase was tap water (density is 998 kg/m\({}^{3}\), dynamic viscosity is 0.001 Pa-s), after filtration by the filter, then the water was fed into the experimental circuit by a liquid centrifugal pump. Two vertical multi-stage centrifugal pumps can be operated simultaneously or separately to meet the requirements of different flow rates; the frequency range of the centrifugal pump motor's frequency conversion is 10 to 50 Hz, the power is 75 kw, the speed is 2970 r/min at rated frequency, the maximum flow rate of a single pump is 998 m\({}^{3}\)/h after the liquid centrifugal pump is equipped with a liquid mass flow meter, it can gauge the liquid phase's density and mass flow rate. Using the pump frequency conversion and PID control of the flow control valve, the flow rate can be accurately adjusted to the desired value. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Total Span (m)** & **Inner Diameter D (m)** & **Wall Thickness (m)** & **Radius of Curvature** \\ \hline
3.6 & 0.048 & 0.006 & 1.5 D \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters of the jumper model. Figure 10: Size of M-shaped rigid jumper. Figure 9: Multiphase flow experiment loop. By controlling the ball valve, the gas-liquid two-phase flow runs into the longer extended development section after the air and water have been mixed in the gas-liquid mixing section and form the fully developed flow into the M-type jumper experimental section.