Churn Flow – Vertical Tubes
Churn flow also referred to as froth flow, is a highly disturbed flow of two-phase fluid flow. The increasing velocity of a slug flow causes the structure of the flow to become unstable. The churn flow is characterized by a very thick and unstable liquid film, with the liquid often oscillating up and down. Due to its nearly chaotic properties, it is one of the least understood gas-liquid flow regimes.
A typical example of churn flow is boiling flow in nuclear reactors during accidents. Especially for many accident scenarios, boiling may lead to a high void fraction, including churn-turbulent flow. Its flow structure and induced pressure changes may have a strong impact on safety.