Study on the instability of FC-72 vapor–liquid interface in a rectangular channel under different gravity conditions

This paper investigates the instability of FC-72 vapor–liquid interface in a rectangular channel under different gravity conditions employing short-term microgravity experimental systems designed based on the drop tower platform. Visual observations and numerical simulations were conducted to monitor the behavior of vapor–liquid interface. The study reveals significant fluctuations, with liquid climbing along both sides of the channel after drop cabin releases. Higher initial liquid levels result in increased maximum liquid phase heights and decreased minimum values, with noticeable fluctuations. In microgravity, the maximum height gradually rises with significant fluctuations, while minimum height remains relatively stable. Increasing contact angle leads to reduced variation in maximum and minimum heights, with a distinctive upward slope of vapor–liquid interface observed at a 90° contact angle. The temporal evolution of vapor–liquid interface observed in simulations closely aligns with experimental findings. This study highlights the importance of considering various factors in designing experiments involving fluid systems with low surface tension, particularly in aerospace applications, and calls for further research to develop more sophisticated models and techniques for understanding and controlling vapor–liquid interface instability.