Parameter estimations, experimental bubble size

Hence there is no simple or direct relation between the observable gas outlet concentration and the kinetic parameters of the gas/solid reaction. The conversion also depends on the rate of mass transfer between the two phases, which varies in a complicated manner with bubble size and rise velocity, particle size distribution, diffusivity, bed geometry, the presence of bed inserts, etc. A number of empirical correlations are available to estimate these parameters. In most modelling studies however, adjustable parameters such as the bubble size are used to fit the experimental data. 

This parameter may either be calculated from the droplet diameter or from empirical correlations. Since the droplet diameter can be of many sizes and is usually unknown, C is estimated from correlations based on experimental data. In one such method by Fair (1961), developed specifically for sieve and bubble cap trays, C is correlated as a function of liquid and vapor flow rates and densities, tray spacing, surface tension, foaming properties, and the ratio of the combined hole area in the tray to its active area. In this correlation, is based on the column cross-sectional area available for vapor flow, A -A, where A is the total tray area (or total inside column cross-sectional area) and A is the downcomer cross-sectional area. The parameter C is given as... 

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