On simultaneous coagulation and diffusional loss of free molecule aerosols in turbulent pipe flow

The population balance equations for simultaneous coagulation and deposition of free molecule aerosols in turbulent pipe flow have been cast in dimensionless form and integrated to obtain a simplified two-equation model. The relative importance of coagulation and deposition is shown to depend upon a dimensionless parameter A, which is a ratio of a characteristic deposition time to a characteristic coagulation time. Solutions to these equations are presented graphically and range from the coagulation-dominated to the deposition-dominated regime. This analysis accounts for the enhancement in coagulation rates due to London-van der Waals attractive forces; this effect is often important for free molecule aerosols. In a separate paper (Brockmann et al., 1982) experimental data are shown to be in good agreement with theoretical predictions.