ISSN Online: 2377-424X
International Heat Transfer Conference 4
MODEL OF CRITICAL HEAT FLUX IN SUBCOOLED FLOW BOILING
Abstrakt
The physical phenomena occurring before and at the critical heat flux (CHF) for subcooled flow boiling of water at moderate pressure are described. Photographic
and electric probe studies with tubes and annuli established that the flow regime is slug or froth flow with intense nucleation at the heater wall. These
observations suggested a new model of CHF based on the formation of a dry spot underneath a vapor clot. Wall temperature measurements, in conjunction with
still or motion pictures, confirmed the microscopic features of the proposed model. The oscillatory wall temperature at CHF could be predicted with appropriate
flow pattern inputs. The proposed model is shown to be qualitatively consistent with parametric trends, including the effect of wall thickness.