Experimental investigation on nanofluid flow boiling heat transfer in a vertical tube under different pressure conditions
Experimental investigation on nanofluid flow boiling heat transfer in a vertical tube under different pressure conditions
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DOI：
10.1016/j.expthermflusci.2016.04.014
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发表时间：
2016-10
影响因子：
3.2
通讯作者：
Yu Wang;G. Su
中科院分区：
文献类型：
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作者：
Yu Wang;G. Su
对直径为20 nm、体积浓度为0.1%、0.5%的γ-Al 2 O3/H2O纳米流体在垂直管内的饱和流动沸腾换热进行了实验研究。采用超声振荡法制备纳米流体。考虑了表面热流密度（50-300 kW m−2）、压力（0.2-0.8 MPa）和质量流量（350-1100 kg m−2s−1）等重要参数对沸腾特性的影响。实验结果表明，与去离子水相比，γ-Al 2 O3/H2O纳米流体的饱和流动沸腾传热最大强化率可达86%，当体积分数为0.1%时，Nusselt数平均值分别提高了23%和45和0.5体积%本研究纳米流体流动沸腾的努塞尔数随表面热流密度、纳米颗粒体积浓度和压力的增大而增大。通过SEM观察证实了纳米颗粒沉积在加热表面上，通过TEM观察证实了纳米颗粒在沸腾后没有明显变化，这归因于超声振荡的连续操作。此外，质量流量对纳米流体饱和流动沸腾传热强化率的影响可以忽略不计。提出了一种适用于纳米流体饱和流动沸腾传热数据处理的无量纲参数。
In this study, the saturated flow boiling heat transfer of γ-Al2O3/H2O nanofluids with 20 nm diameter and 0.1%, 0.5% volume concentration in a vertical tube is experimentally carried out. An ultrasonic oscillation was used to prepare nanofluid. The influences of such important parameters as surface heat flux (50–300 kW m−2), pressure (0.2–0.8 MPa) and mass flux (350–1100 kg m−2s−1) on boiling characteristics are taken into consideration. It is confirmed that the most enhancement is about 86% for γ-Al2O3/H2O nanofluids saturated flow boiling heat transfer compared with deionized water, and the average value of Nusselt number was enhanced 23% and 45% respectively for 0.1 vol.% and 0.5 vol.% in this study. And the Nusselt number of nanofluid flow boiling increases with increasing the surface heat flux, the volume concentration of nanoparticle and pressure. It is confirmed that nanoparticles deposited on the heating surface by SEM observation and nanoparticles do not change obviously after boiling by TEM observations, they are attribute to the continuous operation of ultrasonic oscillation. In addition, the influence of mass flux on the enhancement rate of nanofluid saturated flow boiling heat transfer is negligible. Furthermore, a dimensionless parameter was proposed for nanofluid saturated flow boiling heat transfer data processing.