Subcooled Boiling Critical Heat Flux of Water in Lower Flow Upward in Tubes for Pressure up to 22 MPa

Abstract

An experiment of critical heat flux was conducted in an inconel tube of inner diameter of 7.98 mm and heating length of 0.8 m with water flowing upward, covering the ranges of pressure of 1.96 – 20.4 MPa, mass flux of 476 – 1653 kg/m2s, inlet subcooling of 49 – 346 K and exit subcooling of 1 – 158 K. Based on the experimental result, an empiric correlation was formulated and the parametric trends were studied systematically. A physical model was proposed with assumption of critical thickness of bubbly layer.