Experimental study on boiling instability and occurrence of cavitation in a two-phase square pipe subjected to natural convection

Unsteady boiling bubble behavior of water in a square pipe under a low pressure and subjected to natural convection was experimentally studied. The measurements included temperature and pressure, and the bubble behavior was visualized using a high-speed camera. The boiling phenomena in the pipe showed the three stages characterized by cavitation, intermediate, and fully developed boiling bubble in the Rayleigh number range (1.2–1.6) × 108. …