具有弯曲气液界面的蒸发相变体系的多场测量

Evaporation effect has been given more and more studying interests due to its wide application in new emerging industries, such as microelectronics cooling, self-assembly materials, new medical testing and thermal engineering in space, during which complex heat and mass transfer mechanisms are involved. For the small-scale evaporation system with curved vapor-liquid interface, more applicable experimental technologies are greatly needed to perform measurements of multi-physical parameters, in order to expand previous researches and deepen the mechanisms understanding of evaporating heat transfer. In present proposal, we focus on the abovementioned evaporation systems with curved vapor-liquid interface. For the purpose of constructing an experimental system for multi-fields measurement applying in the evaporating system, we plan to optimize experimental technologies including particle image velocimetry (PIV), infrared thermography and image processing for the morphology of vapor-liquid interface, and try to overcome the encountered difficulities and errors for experimental measurements as following: (1) Deviation of flow rate and absence of the entire flow field caused by the refraction at the curved interface; (2) Deviation of the investigating objects and converted temperature value for the interpretation from infrared photos to temperature fields has induced great difficulties in results analysis; (3) Deviation of morphology measurement for vapor-liquid interface. Utilizing the multi-fields measuring system, quantified measurements of thermocapillary flow field, temperature field neighbouring the vapor-liquid interface, averaged evaporating rate and contact angle could be carried out, and we are going to perform experimental studies of coupling influence of evaporation and thermocapillary convection on the heat and mass transfer in the small-scale evaporation system with curved vapor-liquid interface.

蒸发效应在微电子制冷、自组装新材料制备、新医药检测和空间热能机械等新兴行业领域正得到足够的重视和广泛应用，其过程涉及复杂的热质输运机理。对于具有弯曲气液界面的小尺度蒸发相变体系（液滴、弯月面等），实验观测手段的缺失和不适用限制了对于蒸发传热机理的深入认识，亟需发展新实验技术拓展前人工作和满足多物理参量测量需求。本申请将以上述弯曲界面蒸发相变体系为研究对象，从硬件适用性和软件判读等方面优化PIV、红外热成像技术和界面外形分析技术，克服弯曲界面的光学折射导致流速测量误差和观测范围不覆盖全场、红外热成像图像测量对象判读不准确和温度场反演精度不高导致影响实验目标、界面外形演化测量误差大等问题，完成一套适用于上述蒸发体系的多场测量系统，实现液体内部热对流流场、气液界面温度场、平均蒸发速率和接触角演化等多物理量的定量观测，并用之开展蒸发与热毛细对流耦合影响体系热质传输的实验研究。

蒸发效应在微电子制冷、自组装新材料制备、新医药检测和空间热能机械等新兴行业领域正得到足够的重视和广泛应用，其过程涉及复杂的热质输运机理。对于具有弯曲气液界面的小尺度流体相变体系（液滴、弯月面等），实验观测手段的缺失和不适用限制了对于蒸发传热机理的深入认识，亟需发展新实验技术拓展前人工作和满足多物理参量测量需求。本项目以具有弯曲界面的小尺度相变体系（液滴蒸发和冷凝）为研究对象，通过关键技术攻关和实验测试，建立了一套适用于液滴相变和热对流耦合实验研究的多场、多物理量观测系统，采用红外热成像、界面形貌定量化测量分析、内流场PIV观测等技术，实现了对相变液滴（或液层）内部热对流流场、气液界面温度场、平均蒸发速率和接触角演化等多物理量的定量观测，并用之开展实验工作，研究蒸发相变与热毛细对流耦合机理和对蒸发热质传输特性的影响，观测了冷凝液滴形成、发展演化现象。