| FAN Hongli,QI Haibo,ZHANG Zhao,HAN Rihong,LIU Yubing.CFD-DEM Simulation on Powder Catchment Efficiency in Laser Cladding[J],53(17):146-156 |
| CFD-DEM Simulation on Powder Catchment Efficiency in Laser Cladding |
| Received:October 31, 2023 Revised:December 24, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.17.013 |
| KeyWord:laser cladding powder catchment efficiency CFD-DEM collision process parameter simulation |
| Author | Institution |
| FAN Hongli |
Shijiazhuang Tiedao University, Shijiazhuang , China;Shijiazhuang College of Applied Technology, Shijiazhuang , China |
| QI Haibo |
Shijiazhuang Tiedao University, Shijiazhuang , China;Hebei Key Laboratory of Advanced Materials for Transportation Engineering and Environment, Shijiazhuang , China |
| ZHANG Zhao |
Shijiazhuang Tiedao University, Shijiazhuang , China |
| HAN Rihong |
Shijiazhuang Tiedao University, Shijiazhuang , China;Hebei Key Laboratory of Advanced Materials for Transportation Engineering and Environment, Shijiazhuang , China |
| LIU Yubing |
Shijiazhuang Tiedao University, Shijiazhuang , China |
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| Abstract: |
| It is an advanced surface modification technology by laser cladding which has the characteristics of small heat affected zone, fast repair speed and low dilution rate. It is widely used in aerospace, iron and steel metallurgy, marine engineering equipment, engineering machinery, chemical equipment and other important metal parts repair and remanufacturing. In order to accurately describe the fact that there are collisions among powder, powder tube and substrate during powder flow transportation, and improve the powder catchment efficiency, the influence rules and reasons of powder feed rate, carrier gas flow rate and shield gas flow rate are explored. A gas flow model was established in FLUENT finite element analysis software and particle trajectory model in EDEM discrete element analysis software. Then the coupling interface was developed to obtain the CFD-DEM three-dimensional coupling model which could be used to simulate gas-solid two-phase flow for the whole process of powder flow from nozzle to molten pool. The orthogonal table of the SPSS design center was used to conduct 9 sets of simulation to explore the complex interaction mechanism of the three process parameters of powder feed rate, carrier gas flow rate and shield gas flow rate and their influence on the powder catchment efficiency. Finally, the reliability and accuracy of the model were verified by powder collection test and single pass laser cladding experiment. Orthogonal variance analysis of the powder catchment efficiency showed that the significance difference evaluation F of powder feed rate, carrier gas flow rate and shield gas flow rate were 169.079, 114.317, 50.153 respectively, and the powder catchment efficiency increased first and then decreased with the increase of them. When the carrier gas flow was equal to 11 L/min, the powder flow rate was small relatively, and the powder stopped moving after several near-situ collisions on the substrate, so resulting in a low powder catchment efficiency because they were not captured by the molten pool. With the increase of the carrier gas flow to 13 L/min, the rebound force of the powder after reaching the substrate was enhanced, so that the powder that did not enter the molten pool before could be captured, and the powder catchment efficiency was constantly improved. When the carrier gas flow was increased to 15 L/min, low powder convergence caused by the collisions among powder, powder tube and substrate were intensified, thus reducing the powder utilization rate. When the powder feeding voltage was 14 V to 16 V, the collisions and the powder speed changes were few, most of the powder could enter the melt pool and capture smoothly. The higher the powder feeding voltage, the higher powder catchment efficiency. When the powder feeding voltage was increased to 18 V, the powder quantity and collision increased sharply, making many powders deviate from the previous motion path, and the powder catchment efficiency decreased. When the shield gas flow rate was 8 L/min to 10 L/min, the shield gas had a certain collimation effect, which improved the powder convergence and the catchment efficiency. However, when the shield gas flow rate was greater than 10 L/min, they would cause interference to the carrier gas and reduce the powder catchment efficiency. The laser cladding powder collection test was carried out under two extreme working conditions:powder feeding voltage, carrier gas flow rate and shield gas flow rate were 18 V, 15 L/min, 10 L/min and 14 V, 11 L/min, 8 L/min. The single-pass cladding test was carried out under the laser power of 1 100 W and scanning speed of 5 mm/s. The error of the simulated value and the laser cladding collection powder test value were 4.03% and 4.54%, and the single-pass cladding test value were 16.13% and 16.50%, indicating that the model was accurate and reliable. The CFD-DEM three-dimensional coupling model and orthogonal variance analysis of powder catchment efficiency make clear that powder feed rate has significant effect on the powder catchment efficiency, followed by carrier gas flow rate and shield gas flow rate. The optimal combination parameters of powder feeding voltage 16 V, carrier gas flow rate 13 L/min and shield gas flow rate 10 L/min are confirmed. The research results provide theoretical guidance for the selection and optimization of process parameters in laser cladding. |
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