The longitudinal mixing of liquids flowing successively in pipelines

In the case of two miscible liquids flowing successively in a single pipeline, a mixture of the two media is produced in the region of contact. Current theories for prediction of the volume of this mixture are not reliable. In this study the following matters are discussed: 1. The majority of previous results were reworked and presented in terms of a Taylor dispersion coefficient K and mixing width based on K (Table 1, 2); 2. This work proposes and tests new empirical correlations including the influence of the flow length on the growth of the value of the dispersion coefficient K as well as the influence of the Reynolds' number and concentration boundary upon the final volume of the mixture V m (equations 6, 7, 9); 3. There are compared the predictions of various equations with our own experiments (Table 3) 4. It is pointed out that a Taylor type model is not completely satisfactory, since the dispersion coefficient K seems to increase with length of pipe and not stay constant. ( C max ∼ L −0.5 to −0.6 instead of C max ∼ L −0.5 ). The difference of exponents is a function of Reynolds number.