LAUSR

Abstract Icing in aircraft fuel systems remains a serious issue for aviation safety and security. It is linked to the geometrical properties of the ice particles formed in situ, which are themselves highly sensitive to the operating parameters of the fuel system. In this work, an experimental campaign was conducted with a fuel-icing bench to explore the impact of the interfacial tension ( γ ), the sampling temperature ( θ ) as well as the recirculation time of the particles in the injection loop ( τ ). For this purpose, a new sampling method has been defined, tested and validated, using paraffin oil (PO) as an impregnation product for ice particles. The specimens were prepared, set up in a cryogenic cell and then scanned using X-ray Micro-Computed Tomography (μCT). Image processing and analyses allowed computation of the 3D properties at 5 μ m resolution. The impregnation with PO revealed satisfying results in terms of physical separation of ice particles (more than 66%), especially for the smallest ones ( ⩽ 200 μ m), thus limiting the sintering phenomenon over time. The decrease in γ values showed a slight tendency to form smaller particle size distributions widths ( PSD w ). The observed influence of θ was minor due to its interference with τ , which proved to have the strongest effect on particle size and morphology. Thus, the increase in τ promoted the formation of smaller PSD w with modes ~ 100 μ m. The elongation ( E e ) and flatness ( E f ) form factors showed significant tendencies ( ⩾ 40%) towards rounded and spherical shapes for all ice specimens. The mean curvature distributions showed a trend towards convexities either by decreasing γ or increasing τ values. This study illustrates the complex impact of process parameters on the geometric properties of ice particles in jet fuel. The obtained results may be useful for further testing of filter clogging phenomena or numerical simulation and modeling studies.