摘要
以还原氧化石墨烯(reduced graphene oxide,RGO)纳米流体为实验工质,进行常压下的饱和池沸腾换热特性实验研究,并使用高速摄像机记录沸腾过程中的气泡形态,分析数据和图像结果。实验结果表明:RGO纳米流体对池沸腾的临界热流密度(critical heat flux,CHF)有明显提升作用,使其达到了1684.22kW/m^(2),相较于蒸馏水工质提高了49.2%,但对沸腾换热系数(heat transfer coefficient,HTC)的影响幅度不大,HTC只达到73.87kW/(m^(2)·K),相较于蒸馏水工质提高了2.3%,在相同热流密度下,RGO纳米流体对壁面过热度的影响并不明显。通过对加热表面接触角的测量及汽泡可视化图像的分析发现:RGO纳米流体沸腾过程中在加热表面形成的沉积层是促使CHF提高的核心因素,其改变了加热表面的润湿性和汽化核心数,降低了加热表面气泡的脱离直径,提高了脱离频率,从而实现CHF的延迟出现。
[Objective] Continuous enhancement of energy efficiency is an essential element of China's green development plan to meet the peak carbon dioxide emission target by 2030 and carbon neutrality objective by 2060.Boiling heat transfer,being one of the most effective methods for phase-change heat transfer,is crucial for heat-energy transfer and conversion in various industries.Therefore,improved boiling performance can increase the efficiency,safety,and cost-effectiveness of energy systems.Graphene,a novel material discovered at the turn of the 2lst century,has exceptional properties in numerous fields and can be used as nanoparticles for enhancing the heat transfer of base fluids.This research study aims to enhance boiling heat transfer by examining the effects of the heating surface and working fluids,specifically with graphene nanofluids.[Methods]Reduced graphene oxide(RGO)nanofluid,which is a product of graphene preparation via the redox method,was utilized as the working fluid.The experimental investigation aimed to examine the heat-transfer characteristics of RGO-nanofluid saturated pool boiling at atmospheric pressure.The experimental data were collected and analyzed using a high-speed camera to record the morphology of vapor bubbles during boiling.The research study also used a pool-boiling experiment with a pure copper heating surface and distilled water as the working fluid to provide benchmark data to compare with the RGO nanofluid experiment.[Results]The results indicated that the RGO nanofluids had a significant impact on the critical heat flux(CHF)of pool boiling,which reached 1684.22 kW/m^(2),increased by 49.2% compared to distilled water.However,the nanofluids did not significantly affect the heat transfer coefficient(HTC)of pool boiling,which reached 73.87 kW/(m^(2).K),only increased by 2.3%compared to distilled water.At a constant heat-flow density,the effect of RGO nanofluids on the superheated wall was insignificant.Further analysis of the experimental data revealed that the RGO deposition layer f
作者
黄潇立
陈泽亮
桂南
杨星团
屠基元
姜胜耀
HUANG Xiaoli;CHEN Zeliang;GUI Nan;YANG Xingtuan;TU Jiyuan;JIANG Shengyao(Collaborative Innovation Center of Advanced Nuclear Energy Technology,Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education,Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China;School of Engineering,RMIT University,Melbourne VIC 3083,Australia)
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第8期1291-1296,共6页
Journal of Tsinghua University(Science and Technology)
基金
国家科技重大专项(2011ZX06901-003)。
关键词
还原氧化石墨烯
池沸腾
纳米流体
强化换热
reduced graphene oxide
pool boiling
nanofluid
enhanced heat transfer
