Condensation Heat Transfer Characteristics Of Air-steam Mixture Inside A Horizontal Tube

The passive containment cooling system (PCCS) is an important part of the nuclear power plant to maintain containment integrity under accident conditions. The main equipment is the condensing heat exchanger. As there are a large number of non-condensable gas in the containment, making the steam condensate much more complicated. What's more, due to the horizontal tube internal coagulant liquid distribution inhomogeneity, steam with non-condensable gas condensation analysis is particularly difficult in the horizontal pipe. The steam condensation process in a horizontal tube containing non condensing gas is a complicated gas-liquid two phase flow heat transfer process along with phase change. In this paper, based on the two-phase flow experiments, the flow patterns and condensation heat transfer characteristics of pure steam in the horizontal tube were studied systematically.Furthermore, the effects of various factors on the condensation process were studied. The experimental correlations were established to provide reference for the design of condensation heat transfer equipment. The main research work and results of this paper are as follows:For pure steam condensation process,we build the experimental loop to study the distribution of flow pattern at different flow rates and different pressure. In the heat transfer characteristics, a series experiments have been done to research the impact of the steam inlet flow rate, pressure and the inner wall surface sub-cooling to the steam condensation.An experimental investigation of the local heat transfer characteristic on the role of non-condensable gas during condensation of steam in a horizontal pipe is presented. It analyzes the impact of chan,ges in air quality fraction, test pressure, inlet velocity and other factors to the condensation process.This paper analyzes the influence of the inner wall surface sub-cooling containing non-condensable gases in the steam condensation. In order to expand the experimental range of the inner wall surface sub cooling, and set up air-cooled experimental loop to extend the experimental conditions water cooling loop. Correlations to evaluate the local heat transfer coefficient along the horizontal tubes, in different flow pattern, have been developed and they are in good agreement with the experimental results.