CuO/R141b纳米制冷剂在管内的流动沸腾传热特性

Boiling heat transfer characteristics of nano-refrigerant CuO/R141b flowing in smooth tube

实验研究了CuO/R141b纳米制冷剂在水平管内的流动沸腾传热特性。为了验证实验的可靠性,将纯HCFC141b流动沸腾传热的实验结果与陈民公式进行了比较,计算值与实验值绝对平均误差为7.4%,达到实验精度要求。实验工况:质量流率为100～350kg·m-2·s-1,干度为0.3～0.8,实验段为长1400mm、内径10mm、壁厚1mm的紫铜管。分别研究了不同纳米颗粒质量分数、不同干度、不同流量的传热系数。结果表明:质量流率在120kg·m-2·s-1下,CuO纳米颗粒质量分数为0.1%、0.2%和0.3%时,传热系数分别平均提高了7%、10.4%、16.6%。添加纳米颗粒,强化了管内流动沸腾换热,并且其强化程度与流量、干度和颗粒浓度有关。

The boiling heat transfer characteristics of nano-refrigerant CuO/R141b flowing in a horizontal tube was studied experimentally.In order to verify the reliability of the experiment,the experimental results of boiling heat transfer of flowing pure HCFC141b were compared with Chenmin formula.The absolute average error was 7.4% when compared the calculated value with experimental results,which is satisfactory.The experimental condition was：mass flow rate 100—350 kg·m-2·s-1,vapor quality 0.3—0.8,the total length of copper tube 1.4 m and its inside diameter 10 mm.The heat transfer was investigated at different mass fractions of nanoparticles,different vapor quality and different mass flow rates.The boiling heat transfer is enhanced by adding nanoparticles,and the improvement is related to the mass flow rate,vapor quality and nanoparticle concentration.At the mass flow rate of 120 kg·m-2·s-1 and mass fractions of CuO nanoparticles of 0.1%,0.2% and 0.3%,the heat transfer coefficient increases 7%,10.4%,and 16.6%,respectively.