B206 Experimental Study on Convection-Condensation Heat Transfer Characteristics of High Moisture Flue Gases

概要

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In order to investigate the convection-condensation heat and mass transfer characteristics of the condensing heat exchanger of a gas fired condensing boiler, a single row plain tube heat exchanger is designed, and experiments have been conducted with vapor-air mixture used to simulate the flue gas. Colburn-Hougen method is introduced to analyze the heat and mass transfer process when the vapor in mixture condenses into water on the tube. The influential factors are found as follows : the partial pressure of the vapor, the temperature of the outer tube wall, the mixture temperature, Re and Pr. A new dimensionless number, which is called condensation factor, has been obtained by dimensional analysis. The experimental results show that the convection-condensation heat transfer coefficient is 1.5∿2.5 times that of the forced convection without condensation. Based on the experimental data, the normalized formula of convention-condensation heat transfer is obtained.