CFD-based pre-validation of an in situ optical approach for assessing dust accumulation thickness in pipelines

The accuracy of optical-based in situ measurement of dust accumulation thickness in industrial pipelines is highly susceptible to flow-induced disturbances near the sensor. To address this fundamental issue, this paper presents a computational fluid dynamics-driven approach for the design and pre-validation of a flow-optimized optical structure. Utilizing the discrete phase model and the SST k–ω turbulence model in ANSYS Fluent, we first quantify the vortex formation and flow asymmetry induced by a right-angle prism—a key optical component. Subsequently, we propose an aerodynamic deflector design to streamline the local flow and isolate the prism’s working surface from these disturbances. Our numerical methodology is rigorously validated through comprehensive grid independence and temporal convergence analyses of aerosol deposition. Results demonstrate that the optimized structure effectively suppresses vortex generation and restores a near-undisturbed flow field, reducing velocity deviations from the baseline pipe flow to less than 1% in the critical measurement zone. This ensures that the optical interface does not perturb the natural dust deposition process and provides a stable flow environment for high-fidelity in situ image acquisition. These findings offer a validated numerical foundation for the development of robust pipeline dust monitoring systems.