G060052 Heat Transfer characteristics and Flow Condition of Pure Ammonia and Ammonia/Water Mixtures Evaporating inside an Horizontal Internally Spirally Grooved Tube

Abstract

Heat transfer and flow characteristics of ammonia-water mixture evaporating inside an internally spirally grooved horizontal steel tube with 12mm average inner diameter were investigated with considering the gas-liquid phase equilibrium characteristics of zeotropic mixtures. The circumferentially averaged heat transfer coefficient reached its maximum as the quality approached about 0.6 but decreased abruptly as the quality increased. The circumferentially distribution of wall temperature were also discussed for ammonia-water mixture, and their trend were similar to those for pure ammonia.