微细化沸腾时壁面再湿润与界面破碎耦合机制研究

缺乏针对超高热流密度设备的有效冷却技术是限制航空航天、微电子、核能及新能源技术等领域发展的瓶颈问题之一。气泡微细化沸腾（MEB）是发生在过渡沸腾阶段的传热现象，其传热能力远高于一般的核态沸腾，是解决高释热器件冷却的可行技术之一。由于MEB时的气泡动力学过程明显异于核态沸腾，其传热机制有待进一步阐明。申请人前期发现MEB发生时气膜破碎及由此引起的局部射流与壁面再湿润间存在强关联性，可能是强化MEB传热和避免沸腾危机发生的主要原因。在过往研究基础上，拟利用高速PIV和全反射测量技术，捕捉和分析气膜高频破碎诱发的射流对相界面运动和壁面水-汽相分布的影响，揭示壁面再湿润与界面破碎的耦合作用机制，进而明确MEB抑制沸腾危机发生的原因；同时，通过改变加热面微结构和润湿特性，获取完整的MEB宏观和微观实验数据，建立考虑表面参数影响的精细传热模型，为极端条件下高效热管理技术的开发提供新的思路和解决方案。

The lack of cooling technology for equipment with ultrahigh heat dissipation requirement has been one of bottlenecks limiting the development in the fields of aerospace, microelectronics industry, nuclear power and new energy. Microbubble emission boiling (MEB) is a heat transfer phenomenon occurred in transition boiling region with a stable heat flux over that in normal nucleate boiling, therefore it is a feasible technology for cooling devices with very high heat flux. Due to the significant difference of bubble dynamics from nucleate boiling, the heat transfer mechanism of MEB still remains poorly understood. In the previous study we have demonstrated that there exists strong correlation between the local liquid jet induced by the collapse of vapor film and the rewetting of heating surface, which may be the main reason for avoiding boiling crisis and enhancement of heat transfer in MEB. Based on the previous work, we will capture and analyze the effect of liquid jet induced by the interfacial collapse on motion of interface and vapor-liquid distribution on the heating surface with the aid of high-speed PIV and total reflection techniques. The coupling mechanism of rewetting of heating surface and interfacial collapse will be investigated and illustrated to further understand the mechanism for the inhibition of boiling crisis in MEB region. Meanwhile, by changing the microstructure and wettability of heating surface, the macro and micro experimental data of MEB will be obtained to establish a detailed heat transfer model of MEB with consideration of heating surface parameters, such as wettability, roughness and wicking ability. The implementation this project can provide new idea and avenue for the development of ultra-high-efficient heat transfer technology under extreme conditions.