The test stand essentially consists of a visual cell, temperature and pressure sensors, on-site display devices, a measurement data acquisition system, a cryostat for temperature control of the visual cell, a camera for optical recording with different lenses (endocentric and telecentric lens) and light sources, as well as a computer.
Scheme of the demonstration test rig: CO2 visual cell, 2020 © IKE
During the experiments, the visual cell is heated or cooled along the isochor line which runs through the critical point at a temperature of 30.98 °C and a pressure of 7.38 MPa.
T-s Diagram of CO2, 2020 © IKE
The first video shows the recording of a quasi-static experiment, using a telecentric lens, in which the viewing cell was cooled down from 36 °C to 28 °C in during 12 h.
Video 1, 2020 © IKE
Video 2 shows the recording with the same experimental boundary conditions, but using an endocentric lens.
Video 2, 2020 © IKE
Video 3 shows a dynamic experiment with the telecentric lens in which the viewing cell was also cooled from 36 °C to 28 °C during 30 min.
Video 3, 2020 © IKE
During the recording in video 4 the same experiment was performed with the endocentric lens.
Video 4, 2020 © IKE