THEORETICAL INVESTIGATION OF VAPOR BLANKET VELOCITY BASED ON MASS, ENERGY, AND MOMENTUM BALANCE TO PREDICT CHF AT LOW QUALITY FLOW

Abstract

In this paper a theoretical prediction method of the critical heat flux in flow boiling at low quality is presented based on the liquid sublayer dryout mechanism. The vapor blanket velocity which is the key parameter to predict the DNB type CHF is evaluated by solving mass, energy, and momentum balances simultaneously. The accuracy of the present model is evaluated by comparing model predictions with the experimental data for water. The predictions agree well with the extensive CHF data of water in uniformly heated vertical round tubes.