针对喷射过程中飞行液滴的温度难以准确测量的问题,本文设计了微小液滴温度检测系统。采用该系统测量并得到了液滴初始温度,沉积板预热温度,液滴的冷却速率及其飞行轨迹的环境气体温度。利用快速响应热电偶测量液滴在飞行时的温度,直径为400μm和600μm液滴的冷却速率分别为-3.76℃/mm和-1.82℃/mm。根据液滴的初始温度和冷却速率即可求得其在飞行时的瞬时温度值。依据飞行液滴降温模型,将液滴初始温度和环境气体温度分布函数代入模型的传热控制方程,计算出液滴的冷却速率分别为-4.01℃/mm和-1.99℃/mm。该计算值与实验测量值吻合良好,证明了本文液滴温度测量方法的可行性。
In order to measure the temperature of flying droplet accurately,a measurement system was designed to monitor the temperature of micro droplet.The initial temperature of the droplet,the pre-heat temperature of the substrate,the cooling rate of the droplet and the surrounding gas temperature are collected using the measurement system.The temperatures of the flying droplet along the flying trajectory are sampled with a fast response thermocouple,the obtained result is that the cooling rates of the droplets with diameter of 400 μm and 600 μm are-3.76 ℃/mm and-1.82 ℃/mm,respectively.The instantaneous temperature of the flying droplet can be calculated according to the initial temperature and cooling rate.Based on the cooling model of flying droplet,the initial temperature and surrounding gas temperature are substituted into the heat transfer equation of the model;the cooling rate of flying droplet is calculated.The calculated values of the droplet cooling rate are-4.01 ℃/mm and-1.99 ℃/mm,respectively,which are in good agreement with the experimental data.Experiment and calculation results prove the feasibility of the proposed measurement method.