A procedure of spectrophotometric analysis of fluid flow in pipes is described and its performance is tested on three different dye compounds. The procedure follows measurement and mathematical de-convolution of the signal with an exponential function that is associated with molecular diffusion. Evidence is provided for the presence of segmental flow and the three dye compounds, used as tracer molecules, indicate that the solute molecules gain velocity, predominantly in the streamwise direction, from the solvent flow rate. The additional velocity, as gained from the solvent flow rate, depends on a kinetic-diffusion constant and the internal friction of the system. The model allows a calculation of the flow-injection signal and serves as a tool for the investigation of properties of fluid dynamics.
Physica Scripta, 2000, Vol 62, Issue 4, p. 331-340