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1.
Numerical prediction of the NPSH characteristics in centrifugal pumps
Matej Štefanič, 2025, izvirni znanstveni članek

Opis: This study focuses on the numerical analysis of a centrifugal pump’s suction capability, aiming to reliably predict its suction performance characteristics. The main emphasis of the research was placed on the influence of different turbulence models, the quality of the computational mesh, and the comparison between steady-state and unsteady numerical approaches. The results indicate that steady-state simulations provide an unreliable description of cavitation development, especially at lower flow rates where strong local pressure fluctuations are present. The unsteady k–ω SST model provides the best overall agreement with experimental NPSH3 characteristics, as confirmed by the lowest mean deviation (within the ISO 9906 tolerance band, corresponding to an overall uncertainty of ±5.5%) and by multiple operating points falling entirely within this range. This represents one of the first detailed unsteady CFD verifications of NPSH prediction in centrifugal pumps operating at high rotational speeds (above 2900 rpm), achieving a mean deviation below ±5.5% and demonstrating improved predictive capability compared to conventional steady-state approaches. The analysis also includes an evaluation of the cavitation volume fraction and a depiction of pressure conditions on the impeller as functions of flow rate and inlet pressure. In conclusion, this study highlights the potential of advanced hybrid turbulence models (such as SAS or DES) as a promising direction for future research, which could further improve the prediction of complex cavitation phenomena in centrifugal pumps.
Objavljeno v ReVIS: 12.11.2025; Ogledov: 577; Prenosov: 9
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2.
Characterization and comparative analysis of mechanical parameters of FDM- and SLA-printed ABS materials
Elvis Hozdić, 2024, izvirni znanstveni članek

Opis: This research paper provides an in-depth examination of the mechanical characteristics of 3D-printed specimens made from acrylonitrile butadiene styrene (ABS) and resins akin to ABS, with a focus on two widely used 3D printing methodologies: fused deposition modeling (FDM) and stereolithography (SLA). The study investigates how variations in 3D printing technology and infill density impact mechanical parameters such as Young’s modulus, tensile strength, strain, nominal strain at break, maximum displacement, and maximum force at break. Tensile testing was conducted to assess these critical parameters. The results indicate distinct differences in mechanical performance between FDM- and SLA-printed specimens, with SLA consistently showing superior mechanical parameters, especially in terms of tensile strength, displacement, and Young’s modulus. SLA-printed specimens at 30% infill density exhibited a 38.11% increase in average tensile strength compared to FDM counterparts and at 100% infill density, a 39.57% increase was observed. The average maximum displacement for SLA specimens at 30% infill density showed a 14.96% increase and at 100% infill density, a 30.32% increase was observed compared to FDM specimens. Additionally, the average Young’s modulus for SLA specimens at 30% infill density increased by 17.89% and at 100% infill density, a 13.48% increase was observed, highlighting the superior mechanical properties of SLA-printed ABS-like resin materials. In tensile testing, FDM-printed specimens with 30% infill density showed an average strain of 2.16% and at 100% infill density, a slightly higher deformation of 3.1% was recorded. Conversely, SLA-printed specimens at 30% infill density exhibited a strain of 2.24% and at 100% infill density, a higher strain value of 4.15% was observed. The comparison suggests that increasing the infill density in FDM does not significantly improve deformation resistance, while in SLA, it leads to a substantial increase in deformation, raising questions about the practicality of higher infill densities. The testing data underscore the impact of infill density on the average nominal strain at break, revealing improved performance in FDM and significant strain endurance in SLA. The study concludes that SLA technology offers clear advantages, making it a promising option for producing ABS and ABS-like resin materials with enhanced mechanical properties.
Ključne besede: additive manufacturing, FDM, SLA, ABS filament, ABS resin, mechanical parameters
Objavljeno v ReVIS: 12.01.2024; Ogledov: 2155; Prenosov: 26
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