Tracer distribution models combined

Figure 6 shows a schematic overview of the computational strategy. All quantities listed under model parameters are to be determined by the model. These parameters are combined in the vector of independent parameters p. They have to be initialized to start the calculation (see the literature for initialization strategies), and they will be varied in a systematic way in the course of the calculations. Using the initial independent parameters, the model simulates the distributions of all steady-state (temperature, salinity, oxygen, phosphate, nitrate, total inorganic carbon, alkalinity, and radiocarbon) and transient (CFCs) tracers, as in normal forward models. The simulated tracer concentrations are combined in a vector of dependent parameters p. All dependent... 

Real reactors deviate more or less from these ideal behaviors. Deviations may be detected with re.sidence time distributions (RTD) obtained with the aid of tracer tests. In other cases a mechanism may be postulated and its parameters checked against test data. The commonest models are combinations of CSTRs and PFRs in series and/or parallel. Thus, a stirred tank may be assumed completely mixed in the vicinity of the impeller and in plug flow near the outlet. 

Once the variance of the residence time distribution has been obtained, the axial dispersion coefficient of the tracer g sE is calculated by combining the following equation for the one-dimensional diffusion model (V3) with Eq. (6-28) or Eq. (6-31) ... 

A precise theoretical description of the distribution of the dissolved species after significant movement has stopped requires a combined model of moisture flow and sorption process. However, in segments of the column where flow was sufficiently slow to allow sorption equilibrium, the quantity of tracer can be described by... 

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