摘要
液滴闪蒸广泛应用于余热回收、人工制冰等工业领域。其中剧烈闪蒸会引发液滴沸腾爆炸从而造成闪蒸腔内部结构的损伤,因此研究如何抑制闪爆发生对工业生产安全至关重要。基于高速摄像技术,实验观察了固着液滴(去离子水和脱硫浆液)发生闪爆的过程并记录闪爆发生时间;利用有限元计算方法建立了液滴闪蒸模型,并对单个/多个液滴发生闪蒸时内部流动和传热过程进行了数值模拟。结果表明,液滴初始直径能够直接影响其内部温度变化率,从而控制内部相变过程和液滴闪爆的发生。给出了不同条件下液滴发生闪爆的临界直径,并指出有效抑制闪爆发生的方法,包括提高环境气压、降低液滴初始温度、减小液滴尺寸和使用低导热系数基底。此外,数值结果发现闪蒸过程中液滴内部由热对流主导,并通过对多液滴阵列的三维计算发现闪蒸速率下降是由液滴附近较低的蒸汽浓度梯度造成的。
Droplet flash evaporation is widely used in waste heat recovery,artificial ice making and other industrial fields.The vigorous flash evaporation leads to the flash explosion,which might cause damage to the internal structure of the flash evaporation chamber.Therefore,how to suppress flash explosions for industrial production safety is imperatively studied.With a high-speed camera system,the flash evaporation process of sessile droplets(deionized water and desulfurization slurry)is experimentally investigated and the duration of the flash explosion is recorded.The finite element method establishes the droplet flash evaporation model,and the internal flow and heat transfer process of single/multiple droplets are numerically simulated.The results show that the initial diameter of the droplet can directly affect its internal temperature change rate,thus controlling the internal phase transition process and the occurrence of droplet flash explosion.In this paper,the critical diameter of droplet flash explosion under different conditions and effective methods to suppress flash explosion are pinpointed,including increasing ambient air pressure,reducing the initial temperature of the droplet,reducing droplet size,and using a low thermal conductivity substrate.In addition,the numerical results show that the internal flow of droplets is dominated by thermal convection in the flash evaporation.The three-dimensional simulation of a multi-droplet array shows that the decrease in flash evaporation rate is the low vapor concentration gradient near droplets.
作者
徐世明
周贤
胡蔚帆
李大超
高英伟
李鹏
彭烁
张云鹏
赵烨枫
田远思
李二强
XU Shiming;ZHOU Xian;HU Weifan;LI Dachao;GAO Yingwei;LI Peng;PENG Shuo;ZHANG Yunpeng;ZHAO Yefeng;TIAN Yuansi;LI Erqiang(Huaneng Yingkou Thermal Power Co.,Ltd.,Yingkou 115004,China;School of Low-Carbon Energy and Power Engineering,China University of Mining and Technology,Xuzhou 221116,China;Huaneng Clean Energy Research Institute Co.,Ltd.,Beijing 102209,China;School of Engineering Science,University of Science and Technology of China,Hefei 230027,China)
出处
《西北工业大学学报》
北大核心
2025年第4期774-783,共10页
Journal of Northwestern Polytechnical University
基金
国家自然科学基金(12302350)
陕西省自然科学基金(2023-JC-QN-0083)
中央高校基本科研业务费专项资金(WK2090000072)
中国华能集团有限公司总部科技项目(HNKJ21-H45)资助。
关键词
液滴闪蒸
液滴闪爆
临界直径
有限元方法
脱硫浆液
droplet flash evaporation
droplet flash explosion
critical size
finite element method
desulfurization slurry
