过载下微通道内纳米流体流动沸腾临界热流密度的特性与机理研究

Flow boiling of nanofluids under hypergravity has great potential in aerospace field. This project investigates the characteristics and mechanism of flow boiling critical heat flux (CHF) of nanofluids in micro-channels under hypergravity by using the experimental method primarily with the numerical simulation as an assistant way. The hypergravity is realized through a ground centrifugal machine. This research will obtain the characteristics of flow boiling CHF of nanofluid in micro-channels under hypergravity, reveal the effects of the magnitude, direction and dynamic change of hypergravity as well as the type, size and concentration of nanoparticles on the flow boiling CHF characteristics, establish the numerical simulation method of the flow boiling CHF of nanofluids in micro-channels under hypergravity, propose a predicting correlation of CHF which can meet the design requirement of cooling system of modern high-performance fighter. The flow boiling CHF of nanofluids in micro-channels under hypergravity is complicated, affected by many factors and a new interdisciplinary area. This project will reveal some new characteristics and mechanism, which can not only expand the content and theory of micro-scale flow boiling under hypergravity, but also guide the design and operation of the new on-board cooling system in modern high-performance fighter. Thus, this project has important significance in scientific and application fields.

过载下纳米流体流动沸腾在航空航天领域有很大的应用潜能。本项目采取以实验研究为主，数值模拟研究为辅的方法，对过载下微通道内纳米流体流动沸腾临界热流密度（CHF）的特性与机理进行研究。过载通过地面离心加速转台进行模拟。通过研究，获得过载下微通道内纳米流体流动沸腾CHF的特性；揭示过载大小、方向和动态变化以及纳米颗粒类型、大小和浓度等因素对流动沸腾CHF特性的影响作用和影响机理；建立过载下微通道内纳米流体流动沸腾CHF的数值模拟方法；提出符合现代高性能战机冷却系统设计要求的CHF预测公式。过载下微通道内纳米流体流动沸腾CHF特性复杂，影响因素众多，是一个崭新的多学科交叉领域。开展本项目研究，将揭示一些新的流动沸腾CHF特性与机理，不仅能够丰富过载下微尺度流动沸腾研究的内容和理论，还将直接指导我国新型机载冷却系统的设计和运行。因此，本项目研究具有重要的科学意义和应用价值。

随着战机电子设备热载荷不断增加，传统的制冷技术已无法满足冷却需求。纳米流体流动沸腾是解决这一难题的潜在途径，但机载过载条件下的相关研究十分缺乏。本项目采取数值模拟研究和实验研究相结合的方法，对过载下微通道内流动沸腾的特性和机理进行了研究：（1）开展了微通道内纳米流体流动沸腾的二维数值模拟，获得了纳米颗粒浓度、流量和流向等对临界热流密度的影响；（2）开展了微通道内纳米流体流动沸腾的三维数值模拟，揭示了纳米流体流型的演变过程，发现了纳米流体流动沸腾特性的变化规律；（3）开展了微通道内流动沸腾的实验，获得了流量、热流密度、压力和干度等对流动沸腾特性的影响；（4）开展了过载下流动沸腾的二维数值模拟，揭示了过载对微通道内流动沸腾特性的影响，并可用于纳米流体。本项目以纳米流体流动沸腾研究的科学需求和战机的应用需求为背景，开展了过载下微通道内纳米流体流动沸腾的研究，发现了一些新的流动沸腾现象和特性，并探讨了其发生机制，相关结果不仅可以丰富纳米流体传热研究的内容和理论，还可以为我国新型机载冷却系统的设计提供技术基础。