Film Condensation of the Vapor Flow Behind a Shock Wave on the Shock-Tube Side Wall

Summary

Measurements of film condensation were made in the flow field behind the incident shock wave propagating through a vapor-liquid two-phase medium. Major objective of the study is to identify condensing heat transfer rates of the vapor to the shock-tube side wall and to learn condensation in the main flow. Ethanol and E-10 (a heavy liquid named Afluid by the manufacturer) were extensively used as working fluid. Steady accumulation of the condensing liquid film was confirmed on the wall surface, as similarly seen in the end-wall experiment conducted elsewhere. A most significant result is that “dual-step” shock pressurization was observed in E-10. The first pressure rise is a normal one created by an incident shock front, whereas the second pressure rise is taken place by some large disturbance in the main flow. The reason for this is not certain yet, but is speculated to be relevant to a long relaxation time or inefficient compressibility of the fluid. The visualized shock front and its vicinity of E-10 is completely different from those of normal gases, implying strong condensation in the main flow.