高性能扰流柱-交错内陷槽微流道微细铣削加工及作用机理

Microchannel heat sink provides a good solution for thermal management of high heat-flux devices in microelectric, optoelectronic, chemical and aerospace areas. Nevertheless, their thermal performance is limited by the present design and manufacture method of microchannels with low productivity and high cost. To this aim, we proposed a novel kind of enhanced interconnected reentrant microchannels with pin-fins and their micromilling method in this project. The interconnected reentrant microchannels were fabricated together with the pin fins, and the rough surfaces can be also obtained due to the size effect of micromilling procedure, all of which contributed to the heat transfer enhancement. The main research contents were as follows: The formation and excretion of the chips were investigated in detail, and the wear mechanism was assessed. After the micromilling deformation, cutting force and cutting heat were analyzed, the theoretical model of deformation area and cutting force were developed to reveal the formation process of microchannels. Subsequently, the formations of rough surface and micro burrs during the micromilling process were studied to control their effects on the thermal performance. Besides, the physics of microscale heat and mass transfer in the microchannels was also explored, and the heat transfer enhancement mechanism was revealed. Base on the above works, a system of the structural design, processing method and performance test method of enhanced microchannels was eventually established in order to improve the design and manufacture method as well as the theoretical research level of microchannel heat sinks, which will promote the thermal management technologies for high heat-flux devices.

微通道散热器是解决微电子、光电、化工、航空航天等领域散热难题的理想选择，但目前微流道结构的设计与加工方法制约了其散热性能的提升，并存在加工效率低、成本高等问题。本项目通过计一种新型扰流柱-交错内陷槽微流道结构，提出利用交错微细铣削方法实现交错内陷槽与扰流柱一体化加工成形，并利用尺度效应伴随生成粗糙表面形貌，显著强化微通道散热性能。研究微流道加工切屑生成与排出规律，揭示微铣刀磨损机理；研究微流道交错微铣削变形过程规律，展开微铣削力、热分析，建立加工模型，揭示加工成形机理；探究微流道表面粗糙形貌及微毛刺的生成机理，实现其生成与控制；阐明流-固、热及粗糙表面形貌等多因素耦合作用下的微尺度传热传质机理，揭示强化传热内在机制。并最终建立一套高性能微流道设计、加工与性能测试的理论方法体系，为微流道高效低成本加工提供新的思路，提高我国在微通道散热技术中关键的微流道设计与加工技术与理论研究水平。

微流道散热器是解决微电子、光电、化工、航空航天等领域散热难题的理想选择，但目前微流道结构设计与加工方法制约了其散热性能的提升，并存在加工效率低、成本高等问题。本项目通过设计新型扰流柱-交错内陷槽微流道结构，提出利用交错微细铣削方法达到交错内陷槽与扰流柱的一体化加工成形，实现强化传热微流道的高效低成本加工。主要研究成果如下：1)强化传热微流道微铣削刀具设计：设计了扰流柱-交错内陷槽微流道微铣削加工球头微铣刀，建立了刀具结构模型，分析了刀具结构参数对微流道加工质量的影响规律，实现了刀具结构参数的优化设计；2)微铣削加工成形:揭示了矩形、平行内陷槽、扰流柱-交错内陷槽微流道微铣削加工成形过程规律，阐明了微流道微铣削加工成形机理，建立了工艺参数与微流道粗糙形貌特征及表面质量的映射关系，阐明了微铣削毛刺形成及变化规律，建立了毛刺形成的理论模型，分析了刀具磨损机理，实现了加工工艺参数的优化；3)性能测试与传热传质机理: 实验证实了扰流柱-交错内陷槽微流道在降低壁面温度、强化单相对流及沸腾相变传热等方面的优势，并揭示了其强化传热传质的内在机制，阐明了多场、多因素耦合作用下扰流柱-交错内陷槽微流道微尺度传热传质机理；4)高效微流道散热器应用研究: 开展了强化传热微流道散热器在发动机燃烧室主动冷却、太阳能聚光光伏电池高效冷却中的应用探索，研制了发动机燃烧室微流道主动冷却器原型系统，实验证实了微流道冷却技术在燃烧室主动冷却中的可行性和优异性能，获得了聚光光伏电池内陷槽微流道的高效冷却性能，实现了光伏发电效率的显著提升。. 相关研究成果在包括制造、传热、能源等领域权威期刊在内的国内外SCI刊物上发表论文15篇(含传热顶刊长篇综述1篇)，入选能源领域Top期刊Energy亮点论文1篇，传热顶刊Top25最受关注热点论文1篇。获中国刀协切削先进技术研究会青年新秀奖、省自然科学优秀学术论文奖，指导获省优秀硕士学位论文。受邀担任ASME国际微纳传热传质会议分会场主席。