微多孔表面强化淬火过程中池沸腾传热的试验研究  

Experimental Study of Enhanced Pool Boiling Heat Transfer on Microporous Surface during Quenching Processes

作　　者：张宇鸿 李佳琦[1] 张嘉懿 金梦丽 蒋乐怡 范利武[1,2] 俞自涛[1] ZHANG Yu-hong;LI Jia-qi;ZHANG Jia-yi;JIN Meng-li;JIANG Le-yi;FAN Li-wu;YU Zi-tao(Institute of Thermal Science and Power Systems,Zhejiang University,Hangzhou 310027,China;State Key Laboratory of Clean Energy Utilization,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江大学热工与动力系统研究所,浙江杭州310027 [2]浙江大学能源清洁利用国家重点实验室,浙江杭州310027

出　　处：《高校化学工程学报》2018年第4期794-801,共8页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(51206142)

摘　　要：增加表面亲水性是强化淬火过程沸腾传热、提高淬火速率的有效途径,对工程应用中实现高温物体的快速冷却具有重要意义。通过电化学阴极沉积的方法,在不锈钢柱体表面沉积金属镍颗粒,制备了一种具有较规整三维结构的微多孔超亲水表面。对其在常压饱和去离子水中进行淬火试验,研究其瞬态池沸腾传热特性,并与光滑亲水表面及微粗糙超亲水表面进行对比。结果表明,微多孔表面加快了淬火进程,冷却时间较亲水表面和无孔超亲水表面分别缩短约52%和22%。微多孔表面的临界热流密度较亲水表面提高了33%,但与超亲水表面相比却略有降低。多孔结构的存在产生了"肋片效应",使得表面局部冷却,突起的孔壁更易"刺穿"汽膜,从而使得微多孔表面的Leidenfrost温度较亲水表面与超亲水表面分别提高了约300和190℃。该表面所具有的较强芯吸性也改善了液体对于表面蒸干区域的再润湿能力,加速淬火过程中膜态沸腾向过渡沸腾的转变。Improving surface hydrophilicity is an efficient way to enhance boiling heat transfer during quenching, which is important for rapid cooling of high-temperature objects. Microporous superhydrophilic surface with regular-shaped three-dimensional structure was prepared on stainless steel rodlets by depositing nickel particles via electrochemical cathodic deposition. Quenching experiments were performed in saturated deionized water at atmospheric pressure to study transient pool boiling heat transfer on the microporous surface, and the results were compared with that of smooth hydrophilic surface and micro-roughened superhydrophilic surface. The results show that quenching processes can be accelerated on the microporous surface with cool-down time decrease by 52% and 22% when comparing with the hydrophilic and non-porous superhydrophilic surface, respectively. The critical heat flux on the microporous surface is increased by 33% comparing to the hydrophilic surface, and it is lower than that on the superhydrophilic surface. The Leidenfrost point on the microporous surface is ~300 ℃and ~190 ℃higher than that on the hydrophilic surface and superhydrophilic surface, respectively. The presence of porous structures causes local cooling effects（i.e., fin effects） that destabilize vapor film. Rewetting of dry spots on surface is improved by strong capillary wicking associated with the microporous surface, which leads to accelerated transition from film boiling to transition boiling during quenching.

关 键 词：微多孔表面 淬火 池沸腾传热 超亲水表面 芯吸性 

分 类 号：TK124[动力工程及工程热物理—工程热物理]