發(fā)布時間：2018-07-07 10:12

  本文選題：等離子弧焊接 + 熔池��； 參考：《工程熱物理學(xué)報》2017年05期

【摘要】：本文應(yīng)用基于分子動理論的格子Boltzmann方法,建立了描述定點等離子弧焊接熔池動態(tài)演變過程的二維數(shù)理模型,對相變過程的傳熱與流動現(xiàn)象開展模擬;根據(jù)焊接過程能量分布特點改進等離子弧的組合式熱源模型,采用total-enthalpy模型求解溫度、速度分布及追蹤相界面。研究結(jié)果表明,模擬的熔合線形狀與實驗焊縫吻合,格子Boltzmann模擬得到的計算精度及計算效率均優(yōu)于基于連續(xù)流體假設(shè)的有限容積法,驗證了格子Boltzmann方法用于等離子弧焊接模擬的可行性和優(yōu)越性;熔池中出現(xiàn)兩個方向相反的環(huán)流,流動對焊縫形狀的作用不容忽略;熔池的流動方式影響了溫度場、速度場及二者協(xié)同度,直接影響固相線上的熱量傳遞,促進了焊縫中部凸起的形成。
[Abstract]:In this paper, the lattice Boltzmann method based on molecular dynamics theory is used to establish a two-dimensional mathematical model to describe the dynamic evolution of the molten pool in fixed-point plasma arc welding. The heat transfer and flow phenomena in the process of phase transformation are simulated. The combined heat source model of plasma arc is improved according to the characteristics of welding energy distribution, and the temperature, velocity distribution and tracing phase interface are solved by total-enthalpy model. The results show that the shape of the simulated fusion line is consistent with the experimental weld, and the computational accuracy and efficiency of the lattice Boltzmann simulation are better than that of the finite volume method based on the hypothesis of continuous fluid. The feasibility and superiority of the lattice Boltzmann method in plasma arc welding simulation are verified. The effect of flow on weld shape can not be ignored, and the flow mode of molten pool affects the temperature field. The velocity field and the degree of cooperation between the two directly affect the heat transfer on the solid line and promote the formation of the middle part of the weld.
【作者單位】： 北京科技大學(xué)能源與環(huán)境工程學(xué)院;北京科技大學(xué)冶金工業(yè)節(jié)能減排北京市重點實驗室;山東大學(xué)材料科學(xué)與工程學(xué)院;
【基金】：國家自然科學(xué)基金資助項目(No.50936003)
【分類號】：TG456.2

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