高级检索

    PFA疏水曲面沸腾汽膜输运过程及传热研究

    Study on the transport process and heat transfer of boiling vapor film on PFA hydrophobic surface

    • 摘要: 石油产品是全球必需能源,在全球的需求量日益增大。与此同时,化工厂中液化天然气(LNG)的储存问题也越来越受关注,其中沸腾液体膨胀蒸汽爆炸(BLEVE)是化工厂中最常见的事故,而降低沸腾传热系数(HTC)可有效预防BLEVE事故的发生。相较于亲水表面,疏水表面具有疏水亲汽的特性,使汽泡易于在低热通量下连结成膜,降低HTC。基于表面润湿性原理,将化工厂中不同尺寸球罐等比缩小,研究了不同曲率可熔性聚四氟乙烯(PFA)疏水曲面沸腾过程,结合传热数据和可视化图片将其与光滑铜曲面进行对比。研究结果表明:喷涂了PFA疏水涂层的曲面的临界热流密度(CHF)和HTC显著降低,其中曲率为35−1、47−1、80−1、120−1 mm−1的4种PFA疏水曲面圆心角0°处最高的HTC相较于光滑曲面分别降低了59.5%、80.7%、61.4%、60.0%。

       

      Abstract: Petroleum products are essential energy sources with increasing demand worldwide. At the same time, the storage of liquefied natural gas (LNG) in chemical plants is getting more and more attention, among which the boiling liquid expanding vapor explosion (BLEVE) accidents are the most common accidents in chemical plants, so how to reduce the boiling heat transfer coefficient (HTC) is very important. Compared to hydrophilic surfaces, hydrophobic surfaces have hydrophobic properties, which allow bubbles to link into a film at low heat flux and reduce the HTC. Based on the principle of surface wettability, different sizes of spherical tanks in the chemical plant are scaled down in equal proportions.The boiling process of PFA hydrophobic surfaces with different curvatures was investigated and compared with smooth copper surfaces by combining heat transfer data and visualization pictures. The results show that the critical heat flux density (CHF) and HTC of the surfaces coated with PFA hydrophobic coatings are significantly reduced, in which the highest HTC at the center angle of 0° of the four PFA hydrophobic surfaces with curvatures of 35−1, 47−1, 80−1, and 120−1 mm−1 are reduced by 59.5%, 80.7%, 61.4% and 60.0%, respectively, in comparison with the curved smooth surfaces.

       

    /

    返回文章
    返回