CAJ | 학술논문

向多壁碳纳米管引入羟基基团，改善了其在制冷剂R141b中的分散性和稳定性。同时研究了不同质量分数纳米流体热导率、表面颗粒沉积、接触角变化对核沸腾传热性能的影响。结果表明：羟基化碳纳米流体强化沸腾传热，强化率随质量分数的增加而增加，沸腾后期有所下降。在测试浓度范围内，质量分数为0.05%，热通量为87.4 kW·m?2时，强化率达到最大168%。流体的热导率随着质量分数的增加而增大，质量分数为0.10%时其热导率是纯R141b的1.18倍。分析认为：纳米流体热导率的增加、表面沉积颗粒及纳米颗粒扰动是强化传热的主要影响因素，接触角变化的影响可忽略不计。结论由质量分数为0.03%纳米流体沸腾过程高速成像得到验证。
향다벽탄납미관인입간기기단，개선료기재제랭제R141b중적분산성화은정성。동시연구료불동질량분수납미류체열도솔、표면과립침적、접촉각변화대핵비등전열성능적영향。결과표명：간기화탄납미류체강화비등전열，강화솔수질량분수적증가이증가，비등후기유소하강。재측시농도범위내，질량분수위0.05%，열통량위87.4 kW·m?2시，강화솔체도최대168%。류체적열도솔수착질량분수적증가이증대，질량분수위0.10%시기열도솔시순R141b적1.18배。분석인위：납미류체열도솔적증가、표면침적과립급납미과립우동시강화전열적주요영향인소，접촉각변화적영향가홀략불계。결론유질량분수위0.03%납미류체비등과정고속성상득도험증。
A refrigerant R141b-based nanofluid was made by hydroxylated carbon nano-tube particles in 0.01%, 0.03%, 0.05%, 0.07% and 0.10% mass fractions. An experimental study was carried out to investigate the nucleate boiling heat transfer characteristics of nanofluid on a smooth copper surface at pressure of 90.3 kPa. The surface roughness was made by sandpaper of grade 5000#. The result illustrates that the boiling heat transfer is enhanced by increasing nanoparticles. The improvement is related to the coefficient of thermal conductivity, deposition of nanoparticles and their disturbances to flow. The heat transfer coefficient increases with nanoparticle mass added except in later boiling period. The coefficient of thermal conductivity of 0.10% nanofluid is 1.18 times that of pure fluid R141b. The heat transfer coefficient is increased by 168% for 0.05% mass fraction at the heat flux of 87.4 kW·m?2. The boiling process of 0.03% mass fraction was recorded by the high-speed CCD.