Wall slip of mayonnaises in viscometers

Startup Flow of Gelled Crude Oils: An Experimental Study

“…Slip can also lead to large errors in viscosity estimations and flow rate predictions in these systems [79,115,63,104,78,111]. The dependence of this behavior on factors, such as rheometric geometry and surface conditions, would reveal that it is arising from slip.…”

“…In this situation, possibly the local stress is below the yield value except at the boundary region. So, yielding occurs only at a very thin layer adjacent to the surface, which serves as a lubricating slip film [115,104,133,119,59,131]. In these cases, direct observation techniques, such as visualization, may be required to clarify the situation [78].…”

“…A third signature, which is specific to yield stress materials, is disappearance of yield-stress or a drop in the yield stress value [104,119].…”

“…Slip can also be controlled by changing the physicochemical properties of the surface other than roughness, such as wettability, through chemical treatment or surface coating or by choosing a proper type of material [75,29,102,115,55,104,8,31,53,131,50,125,60,113]. Another means to eliminate or reduce wall slip is to increase surface to volume ratio, although this could complicate the measurement procedures and may not be practical in some circumstances due to experimental restrictions [21,95].…”

“…For example, surfaces are deliberately roughened to reduce the effect of slip [80,71,8,72,115]. This is achieved by various techniques such as serrating, coating, impregnating the surface, abrasive blasting, chemical treatment or attaching solvent-proof sandpapers [115,27,104,23,63,3,8,20,78,74,95,131,97,26,111,40]. Some of these techniques could disturb the system by introducing or modifying other factors than affect slip [93].…”