分子动力学模拟和实验研究铝屑脱油、水技术及机理

Molecular dynamics simulation and experiment study on technology and mechanism of removing oil and water from aluminum chips

通过热重分析、扫描电子显微镜、响应曲面和分子动力学等方法,阐明铝屑脱油脱水的过程和机理。结果表明,铝屑表面切削液在200~300℃质量损失明显,超过400℃时被碳化。水、表面活性剂和油分子在室温下分层排列。表面活性剂中的O—H和水中的O原子之间分别在1.63、3.27和5.05A处存在强氢键、强范德华力和弱范德华力。随着温度的升高,弱范德华力相互作用消失,氢键减弱。超过277℃时强范德华力和氢键被破坏,导致水-表面活性剂-油分层界面的失稳及破坏。在370℃和3 cm装料厚度下加热70 min时,铝屑的油、水脱除率达99.7%。

The processes and mechanism of removing oil and water from aluminum chips were clarified through thermogravimetric analysis(TGA),scanning electron microscopy(SEM),response surface method(RSM)and molecular dynamics(MD).The results indicate that the cutting fluid loses mass obviously at 200-300℃ and is carbonized above 400℃.A layered arrangement of water-surfactant-oil is formed.There are strong hydrogen bonds,strong and weak van der Waals(vdW)forces between O—H in surfactant and O atom in water at 1.63,3.27 and 5.05A,respectively.With the increase of temperature,the weak interaction vdW force is vanished,and the hydrogen bond is reduced.The strong vdW force and hydrogen bonds are broken and the layered arrangement of water-surfactant-oil interface is unstable and destroyed above 277℃.The removal rate of water and oil is up to 99.7% when the chips are heated at 370℃ for 70 min with 3 cm loading thickness.