Combined mass transfer and chemical reaction in an absorbing free laminar stream

The authors analyze the model absorption system consisting of a semi-infinite free laminar jet of liquid surrounded by gaseous atmosphere. At the inlet the liquid contains species A dissolved in it. Gas B is absorbed through the exposed surfaces, dissolves in the liquid, and then undergoes irreversible chemical reaction of the second or higher order with A. The solution constructed represents the entire mass distribution. Thus, it yields useful information concerning the enhancement factor, defined as the ratio between the rate of absorption with and without the chemical reaction. The matched asymptotic expansion technique is used in the proposed solution. Thus, one can recognize two regimes, both when the reaction is very fast or else very slow. In the latter case the process is diffusion dominated close to the inlet and the regime in which the process is reaction dominated is far downstream. If the reaction is very fast, it takes place in a very narrow region which will be called the "reacting layer". In the other regime the derivatives are moderate and it consists of regions which are free of either A or B. The reacting layer separates between these two regions.