表面沉积对氧化石墨烯水悬浮液淬火沸腾特性的影响

Effects of surface deposition on quenching boiling of aqueous suspension with graphene oxide nanosheets

采用淬火法对质量分数为0.002%的氧化石墨烯水悬浮液的瞬态沸腾特性进行了表征。通过对三种代表性工况的对比分析研究了氧化石墨烯在沸腾表面的沉积对淬火沸腾过程的影响。由于氧化石墨烯在过渡沸腾阶段的沉积,水悬浮液的淬火过程较之去离子水缩短了约10 s,临界热通量则提升了约10%,对应的表面接触角从104°减小到78°。将已沉积表面再次在去离子水中淬火后,表面接触角回升到89°,临界热通量则有所回落。结果表明,氧化石墨烯的表面沉积虽然是强化临界热通量的决定性因素,但淬火过程的速率和过渡沸腾阶段的传热速率还受到氧化石墨烯的动态沉积过程和水悬浮液中悬浮氧化石墨烯的共同影响。

The transient boiling of an aqueous suspension with graphene oxide nanosheets （GONs）, at a mass fraction of 0.002%, was characterized using the quenching method. The effects of GONs deposited on the boiling surface were compared among three representative cases. With the deposition of GONs during the transition boiling phase, the quenching period of the suspension was shortened by 10 s as compared to that of deionized water, while the critical heat flux （CHF） was improved by 10%and the contact angle was reduced from 104° to 78°. After subsequent quenching of the boiling surface with GON deposition in deionized water, the contact angle was increased to 89° and the CHF was somewhat deteriorated. It was concluded that the enhancement of CHF is primarily resulted from surface deposition of GONs. The quenching speed and the heat transfer rate during the transition boiling phase are also affected by the dynamic deposition process and the suspended GONs.