The use of photoactivatable fluorophores in the study of turbulent pipe mixing: effects of inlet geometry

The effects of inlet conditions on downstream mixing in turbulent pipe how have been studied with the use of photoactivatable fluorophores and standar d laser-induced fluorescence techniques. The different inlet conditions inc luded both geometry changes and changes in the manner in which the constitu ents were introduced into the how. Results indicate that small changes in i nlet geometry can greatly affect the downstream mixing rate. Changes in the geometry of the inlet had a greater influence on downstream mixing than di d the manner in which constituents were introduced into the how. Further ex periments included a static mixer that was used in conjunction with two dif ferent inlet conditions. It was found that the inlet condition greatly affe cts the effectiveness of the static mixer. The static mixer is most effecti ve when placed downstream of an inlet that produces scalar length scales th at are similar in size to the elements in the mixer (i.e., the pipe diamete r). Overall, the results of these experiments demonstrate that the method u sed to introduce two constituents to be mixed in pipe Row can profoundly af fect the downstream mixing rate.