Prediction of film condensation and aerosol formation in a gas-vapor mixture flow through a vertical tube

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Virginia Tech


A numerical analysis of laminar film condensation and the prediction of aerosol formation is presented for a gas-vapor mixture undergoing forced flow through a vertical tube. This analysis is useful for estimating the sizes and operating conditions of condensers used for removing vapors from gas-vapor mixtures. The ability to predict the possibility of aerosol formation without expensive experimental studies makes it practical to design condensers in which aerosol formation is impossible.

Three different vapors (water, mercury, and benzene) mixed with air are considered in the analysis at three different inlet vapor mass fractions (50% of saturated, 75% of saturated, and saturated). The results indicate that condensers could effectively be used to remove vapors from gas/vapor mixtures and therefore, that design estimates could be determined from the model presented here. The results also show that inlet vapor mass fractions as low as 50% of saturation for water and benzene and 25% of saturation for mercury could cause aerosol formation in the bulk flow field. Aerosol formation degrades the performance of a condenser in removing vapor because the vapor condenses in the bulk flow where it is not easily removed without the use of a filtering medium.