optical investigation of leak discharge
Description
optical investigation of leakage discharge at specimen VS045, VS055, VS060
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The aim of these investigations was to investigate the outflow regime of a selection of specimens with boreholes or pinholes and to document the flow pattern in the outlet flow regime. Therefore, a total of seven specimens or orifices were mounted to the leakage module and investigated regarding the outlet flow regime. The FSI test rig had to be set up in an open configuration in order to investigate the outlet flow regime of the orifices as can be seen in Figure 4. The leakage module, also used for leak rate investigations, had to be equipped with a flange plate to enable a free view onto the leak outflow. The steam is partially collected in an acrylic glass housing which also shields the MotionXtra NX7-S2 high-speed camera. The camera lens itself is protected from outflowing steam by a constant airflow, which takes also away potential drops of water. The leakage, if condensed within the described housing, was collected and pumped back into the test rig. The mass flow rate was not measured during these optical investigations. As can be seen from Figure 4 the leak was held open throughout one complete measurement campaign. To record videos of the outflowing water and steam, the inner temperature of the test rig was risen constantly at a rate of about 70 K/h. The inner pressure was varied in steps of 10 bar and held constant for the duration of the development of stationary conditions and for the 20 s record with the high-speed camera. The videos were handled with a python script that extracts one frame of the recorded video for one parameter set. Three basic outflow patterns with two additional transition patterns could then be distinguished manually from this picture: A pure water jet, a combination of free water jet and a wet steam cone and a pure wet steam cone.