Abstract
CHF characteristics of downward flow are quite different from that of upward flow. In this investigation, CHF experiments were carried out on a forced convective boiling system with a stainless steel tube of 20 mm in inner diameter and 400 mm in heating length. On the basis of the experimental results, typical CHF mechanisms of downward flow were classified into three modes, i.e., the dryout of falling liquid film at high quality condition, CHF due to flooding at low quality condition, CHF caused by the instability of two-phase flow structure at near subcooled condition. These CHF characteristics were estimated by using simple CHF model.
