發(fā)布時(shí)間：2018-10-05 16:08

【摘要】：在激光沉積制造時(shí),粉末匯聚性是保證成形質(zhì)量的關(guān)鍵因素。為了改善粉末的匯聚性,采用氣固兩相流理論對(duì)載氣式同軸送粉噴嘴縱吹氣簾氣壓力大小對(duì)粉末匯聚性影響進(jìn)行了數(shù)值模擬,應(yīng)用FLUENT軟件中的離散相模型計(jì)算了粉末流場(chǎng)速度和濃度分布規(guī)律及匯聚特性。模擬結(jié)果表明,縱吹氣壓力較小(0.3 MPa)時(shí)會(huì)導(dǎo)致粉末流充滿整個(gè)流場(chǎng)域,匯聚性極差;氣壓力較大(0.7MPa)時(shí)同樣粉末匯聚性較差,影響沉積制造成形質(zhì)量;氣壓力為0.5MPa時(shí)匯聚性良好,且在焦點(diǎn)到焦點(diǎn)以下10mm的匯聚區(qū)進(jìn)行激光沉積制造能形成較好的熔池,成形質(zhì)量較好同時(shí)提高了粉末利用率。試驗(yàn)結(jié)果驗(yàn)證了模擬結(jié)果的合理性,數(shù)值模擬結(jié)果對(duì)同軸送粉噴嘴設(shè)計(jì)和結(jié)構(gòu)優(yōu)化具有較大的參考價(jià)值,并解決了現(xiàn)有噴嘴粉末匯聚性較差問(wèn)題。
[Abstract]:In laser deposition, powder aggregation is the key factor to ensure the forming quality. In order to improve the convergency of the powder, the effect of the pressure of the gas curtain on the convergency of the powder was simulated by using the gas-solid two-phase flow theory. The velocity and concentration distribution and convergence characteristics of powder flow field were calculated by using the discrete phase model in FLUENT software. The simulation results show that when the longitudinal blowing pressure is small (0.3 MPa), the powder flow will fill the whole flow field, and the convergence is extremely poor, and when the gas pressure is high (0.7MPa), the powder aggregation is also poor, which affects the quality of deposition manufacturing, and when the gas pressure is 0.5MPa, the aggregation is good. In addition, laser deposition in the convergent region of 10mm from focus to focus can form a better molten pool, and the forming quality is better and the powder utilization ratio is improved. The experimental results verify the rationality of the simulation results. The numerical simulation results have great reference value for the design and structure optimization of coaxial powder feeding nozzles, and solve the problem of poor powder convergence of existing nozzles.
【作者單位】： 沈陽(yáng)航空航天大學(xué)航空制造工藝數(shù)字化國(guó)防重點(diǎn)學(xué)科實(shí)驗(yàn)室;
【基金】：科技重大專項(xiàng)資助項(xiàng)目(項(xiàng)目編號(hào):2013ZX04001-041-04)
【分類號(hào)】：TN249

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