NEW PARADIGMS OF CRITICAL HEAT FLUX PHENOMENON

Abstract

Previous chapters dealt with experimental and analytical investigations of the critical heat flux (CHF) phenomenon under geometrical and operating conditions that are very common in the industry like flow boiling in vertical or horizontal tubes, boiling above the heated surface, and steady state flow. However, there are specific cases where the coolant flow may be oscillating during operating transients or where boiling takes place underneath the heated surface. Similarly, the heated surface may not be flat, but may have curvature of a vessel under consideration. Additionally, the heater may be hollow, having heat flux and coolant flow inside and outside as well as cases on an annular fuel. These conditions need different approaches for the evaluation of CHF owing to the different underlying phenomena. This chapter briefly describes such scenarios requiring CHF evaluation and the methodology followed for evaluating CHF under these specific conditions.