ylihöyrystyminen

Ylihöyrystyminen refers to the phenomenon where a liquid is heated above its boiling point without boiling. This state, known as a superheated liquid, is thermodynamically unstable. If a disturbance, such as the introduction of a nucleation site (like a rough surface, an impurity, or mechanical shock), occurs, the superheated liquid can suddenly and violently boil, a process called nucleate boiling or, in more extreme cases, vapor explosion.

This condition can arise when a liquid is heated in a clean, smooth container, preventing the formation of bubbles that would normally initiate boiling. The absence of nucleation sites means that the liquid can reach temperatures significantly higher than its normal boiling point without vaporization occurring. The energy stored in this superheated state is substantial.

The sudden transition from a liquid to a vapor phase releases this stored energy rapidly. This can lead to a rapid increase in pressure, potentially causing the container to rupture or ejecting the liquid forcefully. Such events can pose significant safety hazards, especially in industrial processes or laboratory settings involving heating liquids. Measures to prevent or control superheating are therefore crucial in many applications. Understanding the conditions that lead to superheating and the mechanisms of subsequent violent boiling is important for ensuring safe handling of heated liquids.