This study numerically investigates the mixing of thixotropic fluids in a groove-embedded partitioned pipe mixer (GPPM). The fluid is modeled using the Moore structure-kinetics model, in which viscosity depends on a structure parameter ( \(\lambda\) ), governed by the competition between shear-induced breakdown and structural recovery. A parametric analysis is performed over wide ranges of the thixotropy number (Th) and destruction parameter ( \({k}_{d}\) ) at Reynolds numbers of \(\text{R}\text{e}=0.1\) and 10, for two plate aspect ratios, \(\alpha =1\) and 2. The coupled evolution of the structure parameter, flow field, and scalar transport is analyzed to clarify the mechanisms responsible for mixing enhancement and suppression. The results show that Th controls the overall degree of structural degradation, whereas \({k}_{d}\) determines the spatial nonuniformity of \(\lambda\) . In creeping flow ( \(\text{R}\text{e}=0.1\) ), mixing is primarily geometry-dominated and thixotropy reduces homogenization. At \(\text{R}\text{e}=10\) , however, the coupling between inertia and thixotropy gives rise to strongly non-monotonic behavior. For \(\alpha =1\) , mixing deteriorates at intermediate Th and improves only at the highest Th examined. For the higher aspect ratio ( \(\alpha =2\) ), inertia does not consistently enhance mixing; instead, it reduces mixing performance near \(\text{T}\text{h}\approx 1\) . Quantification using the intensity of segregation demonstrates that mixer designs optimized for Newtonian fluids do not necessarily ensure efficient mixing of thixotropic materials. These findings highlight the critical role of thixotropy in the design of static mixers.
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