ABSTRACT
Critical heat flux during forced convective subcooled boiling on a rectangular heated surface, being supplied with subcooled liquid through a single round jet or multiple round jets which impinge on the surface has been studied experimentally employing three different liquids of water, R113, and R22 at a pressure from 1 to 25 bar at a high subcooling condition up to 115 K.
According to observation on a variation of flow aspect on the heated surface with an increase in heat flux, characteristics for both the single jet and multiple jets are similar up to the CHF, when focusing on the region controlled by each individual jet. A criterion is proposed that the CHF in the saturated region can be determined from the existing equation for the CHF for the saturated liquid, while for the same heat flux in the subcooled region, an equation can be derived from a simple heat balance on an assumption that the subcooled liquid is heated up at the saturation temperature at the leading edge of the saturation region. By eliminating the length of the subcooled region from the two equations and after revising it slightly, a generalized correlation can be derived, yielding the CHF data not only for the single jet but also for the multiple jets with the same accuracy.
