Fractal behaviour of local liquid—solid mass transfer fluctuations at the wall of a trickle-bed reactor

Abstract

The technique of microelectrodes in a non-conducting wall of a trickle-bed reactor was used to measure the fluctuations of the local liquid-solid mass transfer coefficient (velocity gradient) for different gas and liquid flow rates. The signals obtained have been analysed in terms of fractional Brownian motion (FBM), or more specifically, in terms of Hurst's rescaled range (R/S) analysis, where S, related to the moment of second order of the signal, is supposed to keep, at least, an experimental meaning. This has yielded the estimates for the so-called Hurst exponent, H, of the time series