纳米流体在封闭旋转射流系统中强化换热机理的研究

The technology of rotating impinging jet heat transfer enhancement was widely used in the heat dissipation of the target in accelerator, the cooling of aero engine impeller, the thermal control of electron component and so on. Recent years, nanofluids also were widely studied as a novel working fluids of heat exchange. However, the heat exchange enhancement of nanofluids in rotating impinging jet cooling system is till rarely reported. In the present project, we will make an intensive study of the mechanism of heat exchange enhancement of nanofluids in the rotating impinging jet cooling system by combined two heat enhance technologies rotating impinging jet cooling and nanofulids. First of all, various concentrations Cu-H2O nanoparticles suspension was preparation by one-step method and then the thermal conductivity, the heat capacity and other physical properties parameters were measured; Second, the convective heat exchange phenomenon were studied on self-built thermal test platform; Finally, the mechanism of the heat exchange enhancement of nanofluids in the rotating impinging jet cooling system was numerical studied based on the results of experimental measurement. This study will directly guide the design of the rotating target of high intensive neutron generator.

旋转射流强化传热技术广泛应用在粒子加速器中靶的散热，航空发动机叶片的冷却，电子元器件的热控制等领域。纳米流体作为一种新型强化换热工质近年来也被广泛研究。然而，纳米流体在旋转射流中强化传热的规律目前还鲜有报道。本课题拟结合旋转射流与纳米流体两种强化换热技术，研究纳米流体在旋转射流系统中强化传热的机理。首先，利用一步法制得不同浓度的Cu-H2O纳米悬浮液，测量所得到纳米流体的导热系数，比热容等物性参数，定量分析纳米流体的强化导热现象；其次，利用自行搭建的热工测试平台对纳米流体在封闭旋转射流系统中的强化对流换热规律开展实验研究；最后，对纳米流体在旋转射流系统中的换热过程进行数值建模，结合实验测量的结果与数值仿真技术对纳米流体在旋转射流系统中的换热过程进行系统的研究，对纳米流体在旋转射流系统中的换热机理进行探索。本研究对强流中子发生器中旋转靶的设计具有直接的指导意义。

旋转射流强化换热技术广泛应用在粒子加速器旋转靶散热、航空发动机叶片冷却等，纳米流体作为一种新型强化换热工质近年来也被广泛研究。然而，纳米流体应用于旋转射流系统，在之前的研究中鲜有报道。本项目将纳米流体引入到封闭旋转射流系统中，研究纳米流体在封闭旋转射流系统中的强化换热效果和机理。利用分散法制备了具有不同纳米颗粒体积浓度的Cu-H2O和Al-H2O纳米流体；通过静置观察纳米颗粒沉降现象和利用TEM观测纳米颗粒团聚特性，所制备纳米流体分散稳定性满足实验研究；测量了所制备纳米流体的热导率、比热容和粘度，参考文献模型，建立了不同热物性参数的预测表达式。开展了纳米流体在封闭旋转射流系统中强化换热实验和数值模拟研究，证实了纳米流体在封闭旋转射流系统中的强化换热效果，揭示了纳米颗粒体积浓度、旋转速度和工质入口流速对换热效率的影响规律，阐述了纳米流体在封闭旋转射流系统中的强化换热机理，指出了旋转、射流与纳米流体三种强化换热手段之间的协同/限制作用。本项目研究结果对进一步提高强流中子发生器旋转靶散热能力具有重要的指导意义。