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2. Influence of particle size on powder velocity distribution at the nozzle outlet in Directed Energy DepositionTijan Mede, Andrej Jeromen, Edvard Govekar, Michael Mallon, Matjaž Godec, 2025, izvirni znanstveni članek Povzetek: Metal-based Directed Energy Deposition (DED) is considered one of the variations of additive manufacturing with the highest potential, particularly for space industry and in-orbital manufacturing. The technology however still faces various challenges, many of which can be traced back to poor control and understanding of the powder delivery. Velocity distribution of powder particles at the DED nozzle outlet has a key influence on the results of any predictive model of powder stream and yet remains largely disputed. Certain numerical studies highlighted a possible influence of powder particle size on the velocity condition at the nozzle exit, yet no experimental studies confirmed this effect. The experimental campaign described in this paper quantifies this relation between powder particle size and velocity distribution at the nozzle outlet and a strong decrease of particle speed with particle size is observed. Moreover, smaller particles are observed to travel at speeds higher than the mean carrier gas speed suggesting powder particle segregation within the nozzle as one of the mechanisms driving speed differences at the nozzle outlet.
Ključne besede: directed energy deposition, powder stream, boundary conditions, particle velocity distribution
Objavljeno v DiRROS: 19.09.2025; Ogledov: 727; Prenosov: 460
 Celotno besedilo (3,42 MB)
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3. A coupled fluid-granular approach to modelling powder stream in directed energy depositionTijan Mede, Michael Mallon, Bruno Chareyre, Matjaž Godec, 2024, objavljeni znanstveni prispevek na konferenci Ključne besede: Directed Energy Deposition, powder stream, DEM, CFD, coupled simulation
Objavljeno v DiRROS: 22.08.2025; Ogledov: 994; Prenosov: 768
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4. A coupled convective-diffusive model of heat transfer and melt-pool dynamics in additive manufacturingTijan Mede, Matjaž Godec, 2024, elaborat, predštudija, študija Ključne besede: additive manufacturing, selective laser melting, laser powder-bed fusion, melt-pool, heat transfer, convection
Objavljeno v DiRROS: 05.04.2024; Ogledov: 2728; Prenosov: 0 |
5. Relevance of inter-particle interaction in directed energy deposition powder streamTijan Mede, Matjaž Godec, 2024, izvirni znanstveni članek Povzetek: Blown powder dynamics is one of the aspects of Directed Energy Deposition (DED) with a major influence on deposition quality and potential for improvement in simulation. Most currently employed computational models discard powder grain collisions as negligible, although little explicit evidence for that claim exists. A Discrete Element Method approach is thus employed in the present work to simulate the actual number of grain collisions in a powder stream of a commercial discrete coaxial nozzle and how that number varies with the key processing parameters. While the number of powder grain collisions is found to in fact be negligible at one side of the usable parameter spectrum, the opposite side results in as many as 84% of all the powder grains being involved in inter-granular collisions with an average rebound angle of 14◦, challenging the established hypothesis of the negligibility of this phenomena.
Ključne besede: DED, powder stream, grain collisions, DEM
Objavljeno v DiRROS: 31.01.2024; Ogledov: 1755; Prenosov: 1006
Celotno besedilo (1,65 MB)
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