Condensation Heat Transfer on Tubes in Actual Flue Gas. Experiment using Flue Gas at Different Air Ratios.

Abstract

In order to improve a boiler efficiency, latent heat recovery from the flue gas is very important concept. Condensation heat transfer on horizontal stainless steel tubes was investigated experimentally by using an actual flue gas from a natural gas boiler. The experiment was conducted at different air ratios of the flue gas and wide range of tube wall temperatures. The condensation pattern was similar to a dropwise condensation near the dew point. Decreasing the wall temperature, the wall region covered with a thin liquid film increased. The heat and mass transfer behavior was well predicted with the analogy correlation at the high wall temperature region. At the low wall temperature region, the total heat transfer was higher than that predicted by the analogy correlation.