Enabling a Leidenfrost drop to perform Biellmann spin

Leidenfrost phenomenon refers to the levitation of a liquid drop on a sufficiently hot surface and has been studied since its discovery in 1756. Extensive research has explored this effect across both liquids and solids, uncovering fascinating behaviours and intricate underlying mechanisms. However, most research on this phenomenon only focused on unrestricted drops, such as self-rotating motions, trampolining, and manipulating substrate morphology to control drop motions, few reports have explored the behaviour of a restricted Leidenfrost drop due to the significant challenge to manipulate a highly mobile levitating drop. Here we report a new phenomenon of a high-speed spinning Leidenfrost drop by confining both its vertical and horizontal movements. We term this phenomenon the Biellmann-Leidenfrost spin because it is reminiscent of the Biellmann spin in figure skating. This phenomenon originates from the vertical restriction on a Leidenfrost drop that initiates star-like oscillations, and is enhanced when the drop satisfies the double resonance conditions, enabling a maximum angular velocity of ~ 1700 r/min, and can be sustained by replenishing water. The Biellmann-Leidenfrost effect holds significant potential for converting waste heat into mechanical energy, for applications in energy conversion and conservation.