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本研究以微槽道结构蒸发器为研究对象,以TiO_2/R141b纳米流体为工作介质,在不同运行压力条件、不同纳米流体体积分数下对蒸发器的传热特性进行了实验研究。运行压力为0.86×10~5 Pa、1.0×10~5 Pa,纳米颗粒的体积分数范围为0.001%～0.1%。运行压力为0.86×10~5 Pa时,体积分数为0.001%、0.01%纳米流体会具有明显的强化换热的效果;体积分数为0.1%的纳米流体在高热流密度时出现传热恶化的状况。在运行压力为1.0×10~5 Pa时,体积分数为0.001%、0.01%的强化效果不明显,而体积分数为0.1%的纳米流体随着压力的增加,传热恶化程度加剧。本研究还对纯工质在微槽道结构表面纳米颗粒沉积层的蒸发/沸腾传热特性进行了实验研究,实验结果表明:纳米粒子沉积层的存在对纳米流体在微槽道结构内蒸发/传热特性具有重要的影响。
In this study, the micro-channel evaporator was taken as the research object, and the heat transfer characteristics of the evaporator under different operating pressure and different volume fraction of nanofluid were experimentally studied using TiO 2 / R141b nanofluid as the working medium. The operating pressure is 0.86 × 10 ~ 5Pa, 1.0 × 10 ~ 5Pa, and the volume fraction of nanoparticles is 0.001% ~ 0.1%. When the operating pressure is 0.86 × 10 ~ 5 Pa, the volume fraction is 0.001%, and the effect of heat transfer enhancement is obvious with 0.01% nanofluid. The nanofluid with the volume fraction of 0.1% . When the operating pressure is 1.0 × 10 ~ 5 Pa, the volume fraction is 0.001% and the enhancement effect of 0.01% is not obvious. The nanofluid with the volume fraction of 0.1% increases with the increase of pressure, which aggravates the heat transfer deterioration. In this study, the evaporation / boiling heat transfer characteristics of pure working medium on the deposition of nano-particles on the micro-channel surface were also studied. The experimental results show that the existence of nano-particles on the evaporation of the nanofluid in the micro-channel structure / Heat transfer characteristics have a significant impact.