纳米润滑剂，即分散在制冷剂和油混合物的非挥发性成分中的纳米颗粒，已显示出增强制冷系统蒸发器传热的潜力。文献中提供的两相流沸腾传热系数叠加模型使用Dddittus Boelter或Gnielinski关联式预测对流传热率，Forster-Zuber或Cooper关联式估计核沸腾传热率。这些关联式不能解释两相流中纳米颗粒的存在，也不能预测制冷剂和负载纳米颗粒的润滑剂混合物的流动沸腾实验中观察到的传热增强，有时甚至退化。通过修改和集成最初为纳米流体开发的现有对流传热模型和纳米润滑剂的池沸腾模型，开发了一种新的综合模型。 新开发的模型考虑了纳米粒子与基础流体的相互作用，通过将动量从纳米粒子传递到气泡来增加传热，并在纳米粒子与基础流体之间的界面引入滑移速度效应。利用光滑铜管中R410A与两种纳米润滑剂饱和两相流沸腾的实验数据，验证了新的叠加模型。这两种纳米润滑剂具有分散在聚烯醚（POE）润滑剂中的非球形ZnO纳米粒子和球形γ-Al2O3纳米粒子。模型结果符合数据趋势，证实湍流中低浓度纳米颗粒的存在增加了层流亚层的厚度。 这种现象是观察到的两相流蒸发传热减少的原因。然而，该模型预测，当将纳米颗粒限制在流体的层流子层内时，传热可能会增强。引用:佛罗里达州奥兰多2020年冬季会议论文

Nanolubricants, that is, nanoparticles dispersed in the non-volatile component of a refrigerant and oil mixture, have shown potential to augment heattransfer in the evaporators of refrigeration systems. The two-phase flow boiling heat transfer coefficient superposition models, available in the literature, usedDittus-Boelter or Gnielinski correlations to predict convective heat transfer rates, and Forster-Zuber or Cooper correlations to estimate the nucleate boilingheat transfer rates. These correlations do not account for the presence of nanoparticles in the two-phase flow and cannot predict the heat transfer enhancements,or sometimes degradation, observed during flow boiling experiments of refrigerant and nanoparticle laden lubricant mixtures. A new comprehensive modelwas developed by modifying and integrating existing convective heat transfer models originally developed for nanofluids and pool boiling models fornanolubricants. The newly developed model accounts for the interactions of nanoparticles with the base fluids in terms of increasing the heat transfer bytransfer of momentum from the nanoparticles to the bubbles, and introducing slip velocity effects at the interface between the nanoparticles and the base fluid.Experimental heat transfer data of the saturated two-phase flow boiling of R410A with two nanolubricants in a smooth copper tube were used to validatethe new superposition model. The two nanolubricants had non-spherical ZnO nanoparticles and spherical γ-Al2O3 nanoparticles dispersed in Polyolester(POE) lubricant. The model results followed the data trends and confirmed that the presence of low concentrations of nanoparticles in the turbulent flowincreased the laminar sublayer thickness. This phenomenon was responsible for the observed decrease of the two-phase flow evaporative heat transfer.However, the model predicted potential enhancements in heat transfer when constraining the nanoparticles within the laminar sublayer of the flow.