微通道内磁流体沸腾传热特性研究

Boiling Heat Transfer Characteristics of Fe_3O_4 Magnetic Fluid in Rectangular Micro-channel

为研究磁流体在微通道中沸腾传热的规律及性质,以去离子水和质量分数为0.5%的Fe3O4-水磁流体为实验工质,在0.6mm×2mm的微槽道中进行对比实验研究,分析了不同的质量流速、热流密度、磁场强度等因素对沸腾传热系数的影响,将实验所得数据与相关沸腾传热模型进行对比,结果表明,随着热流密度和质量流速的增加,微槽内磁流体的沸腾传热系数增大;实验范围内磁场强度对微槽内磁流体沸腾传热系数影响较小;在相同的条件下,磁流体可强化微通道内的沸腾传热,且强化作用随雷诺数的增加而增大;以核态沸腾为主的微槽相变传热计算模型的预测效果较好。

To study boiling heat transfer of magnetic fluid in the micro‐channel ,the contrast ex‐perimental researches of phase‐change heat transfer were carried out in the aluminum rectangular micro‐channels with a width of 0 .6 mm and height of 2 mm .The deionized water and the water based on Fe3 O4 magnetic fluid with the mass fraction of 0 .5% were used as the working fluids . The effect of the mass flow rate ,the heat flux density and the magnetic field intensity on boiling heat transfer coefficient of magnetic fluids were investigated .Finally ,the experimental data were compared with related models of boiling heat transfer coefficient .In comparison ,the boiling heat transfer coefficient of Fe3 O4 magnetic fluid in rectangular micro‐channel increased with the in‐crease of the heat flux density , mass flow rate . In experimental conditions , the boiling heat transfer coefficient of magnetic fluid in micro‐channel was little influenced by the magnetic field intensity .It also confirmed that compared with deionized water ,the boiling heat transfer coeffi‐cient in rectangular micro‐channels can be consolidated by using the water/Fe3 O4 magnetic fluid and it’s enhancement effect increased with the Reynolds number increased .Phase change heat transfer calculation models in micro‐channel based on nucleate boiling achieved more accurate pre‐diction .