Leidenfrost Effect to Reduce Drag on Submarine

Abstract

Heating process and boiling on a surface on which liquid falls is familiar in our daily lives, and occur in many thermally related industries. Consider a bowl or pan containing a liquid which is heated at regular intervals, the liquid will start to boil, with vapor bubbles forming at the hot surface. When it nears nucleate-boiling phase. if the surface temperature is increased further, a continuous vapour film will form that leads to the film-boiling or Leidenfrost vapor formation. We know that surface properties such as roughness and wettability can alter the transition temperature from the nucleate-boiling to transition boiling to the film-boiling phase. Leidenfrost vapor is formed at this temperature and studies have shown that it reduces drag effectively. Main focus of this analysis is to compare drag coefficient of naval bodies at STP conditions to Leidenfrost temperature (approx. 200 C ) for water.