微通道内纳米流体的流动与换热特性

以不同浓度的TiO₂-水纳米流体和水为冷却工质,在扇形微通道热沉内进行流动和换热特性模拟和实验研究.模拟采用有限体积法的两相混合模型,搭建了能测量纳米流体流量、进出口压降和温度、底面加热膜温度的实验系统;工质在微通道内的雷诺数处于207~465,加热膜热流密度为2×10⁶W/m².结果显示:在扇形微通道内,纳米流体的摩擦阻力系数随Re变化趋势与水相似,且均比水大;随着Re的增大,各工质的摩擦阻力系数下降.纳米流体的传热性能强于水;随着TiO₂纳米颗粒浓度和Re的增大,Nu升高,纳米流体的强化传热能力随之提高.

Hydraulic and Thermal Characteristics of Nanofluid in Microchannel

This paper presents a simulative and experimental investigation of the thermal and hydraulic fields of the TiO2-water nanofluids with various concentrations inside a fan-microchannel heat sink. The computational method of simulation was a two-phase mixture model. The nanofluids flow and heat transfer facility which could measure flow rate, import and export of pressure drop and temperature and the temperature of heating film was set up for the experiment. Reynolds number of coolant in the microchannel was between 207~465 and the heat flux of heating film was kept in 2 × 106 W/m2 . The results show that the relationship between the friction factor and Re of nanofluids is similar to that of water within the fan-microchannel and the friction factor is larger than that of water. The friction factor decreases while the Re increases. The heat transfer performance of nanofluids is better than that of water. Furthermore, the heat transfer enhancement of nanofluids increases with increasing Re and the concentration of nanoparticles.