A Comparative Study on Early‐Stage Icing Evaluation Techniques for Passive Ice Protection Systems

ABSTRACT Passive Ice Protection Systems (PIPSs) aim to delay or prevent icing by tailoring surface properties rather than relying on active heating or chemical agents. While various methods have been proposed to evaluate their performance, a lack of standardized protocols has led to fragmented and often incomparable data. This issue is particularly critical for the early stages of ice nucleation, which are the most relevant to understanding and predicting a surface's true anti‐icing behavior. In this work, we critically assess the experimental approaches used to study early‐stage icing phenomena. We developed a versatile climate chamber, called the ICE‐CUBE, capable of replicating the tests reported in the literature under controlled conditions. To validate the setup, we employed a hydrophilic silicon surface as a reference and a sol–gel‐derived hydrophobic coating as a model PIPS. We performed the following tests: cycles of frosting/defrosting, freezing delay time, freezing probability, nucleation site density, dynamic contact angle and sliding angle. Each test was assessed for its relevance and informativeness in the context of early‐stage icing. Our analysis highlights that only a subset of these tests, specifically cycles of frosting/defrosting, freezing delay time and freezing probability, are essential for reliably screening the anti‐icing performance of PIPSs.