Vapor condensation behind a shock wave propagating through a large molecular-mass medium

Abstract

Measurements of film condensation were made 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 as well as to learn the condensing main flow field. Ethanol and E-10 (a heavy liquid named Afluid by the manufacturer) were extensively used as working fluid. Steady accumulation of the condensing vapor 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 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.