Effect of turbulence enhancement on crude oil fouling in a batch stirred cell

A simple batch stirred cell (Young et al., 2011) has been used to investigate crude oil fouling on bare mild steel test probes and on similar probes fitted with thin wires used to promote turbulence and increase surface shear stresses. The results show that, under otherwise identical operating conditions, the fouling rate on the surface of the probe fitted with wires was significantly lower than that on the surface of the bare probe. Moreover, the fouling resistance data using the wired probe were seen to be much more scattered over time, which suggests that the additional turbulence, and hence the associated additional shear stress, and perhaps even the associated uneven circumferential shear stress distribution, were all creating a greater random removal of the fouling deposit from the surface. CFD simulations of the fluid flow for both the bare and wired probes were conducted using the commercial multiphysics package Comsol 4.2. The simulation results show that, for otherwise identical conditions, the shear stress on the wired probe was significantly greater than that on original bare probe even at the point of lowest circumferential shear stress. The CFD results thereby allowed better interpretation of the experimental fouling data on the enhanced surface.