Application of TiH2 dehydrogenation for vapour layer formation under boiling crisis conditions

Abstract

This study explores TiH2 dehydrogenation for vapor layer formation under boiling crisis [1] conditions, aiming to reduce friction in the maritime sector. Despite the rise of electric vehicles for urban transport, marine vessels lack alternatives to fossil fuels. The research aims to combine compliant surfaces with two-phase flow generation, focusing on testing TiH2 (TH-2). Moreover, the study highlights the need for hydrogen-generating materials and suggests that material choices influence two-phase flow initiation conditions. After conducting experiments, it was determined that TiH2 affects the cooling dynamics: at the initial time moment, the cooling of the samples coated in TiH2 was more intense compared to polished aluminum samples (AL-1) due to the hydrophilic properties of the surface. When the TiH2-coated sample temperature dropped to approx. 200 °C, the cooling process would slow down, or the process would temporarily become isothermic (in some cases, a slight increase in temperature was observed as well) due to the formation of TiO2 or Al2O3, both of which are exothermic reactions. Dehydrogenation likely only takes place at the initial time moment and when the conditions for the Leidenfrost effect are favorable, which would serve to sustain the high temperature of the sample. It was concluded that the amount of accumulated hydrogen gas in cases of TH-2 samples was insufficient to cause a significant effect on critical Leidenfrost temperature. Nevertheless, a significant difference in heat transfer coefficient between AL-1 samples and TH-2 was observed due to physical–chemical processes on the TiH2 film.