Coagulation constant

The minimum coagulation constant occurs for coagulation of equal-size particles. This can be seen in Fig. 18.1 which shows a three-dimensional graph of the coagulation constant matrix. The valley indicated on the plot represents the constants for coagulation of equal-size particles. 

Example 18.2 Determine the value for the coagulation constant K0 for air at 20°C and standard pressure for particles having Cc = 1. 

Using K0 as the coagulation constant and neglecting the second term in Eq. 18.9 yield the usual form of the coagulation equation ... 

Equation 18.12 shows that the inverse of the concentration at any time is a linear function of time, the slope of the line being determined by the coagulation constant. Experimental data from both mono-disperse and polydisperse aerosols follow this general form, at least initially. As will be discussed later, the coagulation constant may be appreciably larger than the theoretical value. If th is defined as the half-value time, i.e., the time in which the concentration decreases by a factor of 2, then... 

The rate of coagulation, as expressed in the value of the coagulation constant is actually considerably greater than that given above, and this is due to three factors -... 

The results of the numerical calculation are shown in Fig, 7.8, where they are compared with numerical calculations carried out for the discrete spectrum starting with an initially monodisperse system. There is good agreement between the two methods of calculation. Other calculations indicate that the similarity form is an asymptotic solution independent of the initial distributions so far studied. The values of a and b were found to be 0.9046 and 1.248, respectively. By (7,75) this corresponds to a 6.5% increase in the coagulation constant compared with the value for a monodisperse aerosol (7.21). The results of more recent calculations using a discrete sectional method are shown in Table 7.2. 

Determine the coagulation constant from these data and compare with theory for monodis-perse and self-preserving aero.sols. 

The coagulation constant K figuring in the kinetic equation of coagulation (11.1), is, by its physical meaning, equal to the collision frequency of drops with unit concentration, therefore... 

In a laminar flow, the coagulation constant K is proportional to the capture cross section of bubbles of volume to by a bubble of volume V, while in a turbulent flow, it is proportional to the flux of bubbles of volume w towards the test bubble of volume V. 

Ablation factor of separator Dimensionless parameter Kernel of kinetic equation (coagulation constant)... 

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