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含颗粒液滴蒸发是自然界和工业生产中常见和重要的热质传递现象,其蒸发流动和沉积特性机理尚有待深入揭示。本文直接采用荧光示踪纳米颗粒,研究含颗粒的去离子水液滴在不同颗粒浓度和乙醇浓度条件下的蒸发特性和沉积特性。同时,借助纳米PIV技术获得液滴近壁区尤其是三相接触线附近的速度场。实验结果表明,随颗粒浓度和乙醇浓度的改变,液滴的内部流场发生很大的变化,最终沉积图案也有明显差异。最后,通过初步的理论分析解释了其内部流场和最终沉积变化的原因。
Particle droplets evaporation is a common and important heat and mass transfer phenomena in nature and industrial production. The mechanism of evaporation flow and deposition characteristics remains to be further revealed. In this paper, the fluorescence tracing nanoparticles were directly used to study the evaporation characteristics and deposition characteristics of droplets containing deionized water with different particle concentration and ethanol concentration. At the same time, with Nano-PIV technique, the velocities near the three-phase contact lines are obtained near the wall. Experimental results show that with the changes of particle concentration and ethanol concentration, the internal flow field of droplets changes greatly, and the final deposition pattern also has significant differences. Finally, the reasons for the changes of the internal flow field and the final sediment are explained through the preliminary theoretical analysis.