基于相变膨胀释能的防结冰方法试验研究

发布时间：2018-07-18 15:24

【摘要】：结冰引起的附着和积累现象影响人们的生产和生活,造成经济损失甚至是人身安全事故。本文基于相变膨胀释能现象提出一种防结冰方法,进行方案设计,指出研究思路的理论来源并提出具体研究思路及技术路线。利用不同液体的相变时差,通过约束接触边界的方法来加强结冰相变所产生的膨胀力。试验观察冷表面上和冷环境中的水结冰相变规律及膨胀形变效应,分析水结冰相变过程的对外特性。制备了基于相变膨胀释能的防结冰覆膜模型,并进行性能试验。对防结冰覆膜模型进行优化分析及验证试验。本文的主要工作和结论如下。(1)本文针对冷表面上和冷环境中的水结冰相变现象进行试验研究,包括结冰过程中水滴形态变化规律、水滴内温度变化规律、相变时长特性、体积膨胀特性。试验采用观察和测量计算的方法,揭示水结冰相变过程的对外特性。研究发现,结冰过程中,水滴形态先后为清晰原始状态、浑浊的过冷状态、冰界面形成、冰界面上移、水滴顶部出现凸起、直至相变完成。水滴内温度先后经历快速降温、平稳过冷、温度骤然升高又快速下降、逐渐平稳阶段。结冰相变时长受水滴尺寸影响,水滴尺寸越大,结冰相变时间越长。溶液结冰体积膨胀显著,且体积膨胀主要发生在相变阶段。(2)基于相变膨胀释能制备一种防结冰覆膜模型,用模型验证基于相变膨胀释能的防结冰方法的可行性,研究覆膜模型对结冰切向粘附强度的影响效果。以结冰切向力为指标进行结冰、除冰测试,分析低冰点溶液浓度对结冰切向力的影响,观察结冰后的覆膜模型表面和冰界面的形态。研究发现防结冰覆膜模型的结冰切向粘附强度明显低于未经处理的样件,低冰点溶液浓度越低,降低结冰切向粘附强度的效果越好。凹坑内填充低冰点溶液的防结冰覆膜模型结冰后,其冰界面呈现无规则凹凸不平结构,且中心处凹陷最大。(3)以结冰切向力为测试指标,通过试验优化和测试手段来研究最优防结冰覆膜模型,进行方差分析、最优覆膜模型验证、模拟实际自然环境结冰测试。研究发现,降低结冰切向力的影响主次因素为低冰点溶液浓度凹坑深度凹坑直径。当乙醇溶液浓度为6%,凹坑直径为22mm,凹坑深度为4.7mm时,防结冰覆膜模型最优,降低结冰切向粘附强度的效果最好。应用最优防结冰覆膜模型后,对于0.08g/m L杂质含量的水,可降低结冰切向粘附强度达56.36%。杂质含量越少,覆膜模型降低结冰切向粘附强度的效果越好。
[Abstract]:The phenomenon of attachment and accumulation caused by ice affects people's production and life, and results in economic losses and even personal safety accidents. In this paper, based on the phenomenon of phase change expansion and energy release, an anti-icing method is proposed, and the scheme design is carried out. The theoretical source of the research ideas is pointed out, and the specific research ideas and technical routes are put forward. In this paper, the expansion force of ice phase transition is strengthened by limiting the contact boundary by using phase change time difference of different liquids. The law of water ice phase transition and the effect of expansion deformation on cold surface and cold environment were observed, and the external characteristics of water ice phase transition were analyzed. An anti-icing film model based on phase change expansion release was prepared and its performance was tested. The model of anti-icing film was optimized and verified. The main work and conclusions of this paper are as follows: (1) the phenomena of water freezing phase transition on cold surface and in cold environment are studied in this paper, including the change of water droplet morphology, the variation of temperature in water droplet, and the characteristics of phase transition duration. Volume expansion property. The external characteristics of the process of water freezing phase transition are revealed by means of observation and measurement. It is found that the droplet morphology in the process of ice formation is a clear primitive state, a turbid supercooled state, ice interface formation, ice interface moving up and the top of the water droplet protruding until the phase transition is completed. The temperature in water droplets has experienced rapid cooling, steady undercooling, sudden rise of temperature, rapid decrease, and gradually stable stage. The length of freezing phase transition is affected by the size of water droplet, the larger the size of water droplet, the longer the time of freezing phase transition. The volume expansion of the solution is significant, and the volume expansion mainly occurs in the phase change stage. (2) based on the phase change expansion energy release, a kind of anti-icing film model is prepared, and the model is used to verify the feasibility of the anti-icing method based on the phase-change expansion energy release method. The effect of film mulching model on the tangential adhesion strength of ice was studied. The effect of the concentration of low freezing point solution on the freezing tangential force was analyzed, and the morphology of the surface and the ice interface of the ice-coated model was observed. It was found that the freezing tangential adhesion strength of the model was obviously lower than that of the untreated sample, and the lower the concentration of the solution at the low freezing point, the better the effect of reducing the ice tangential adhesion strength. The ice interface of the anti-icing film model filled with low freezing point solution in the pit is irregular and uneven, and the hollow in the center is the largest. (3) the ice tangential force is taken as the test index. The optimal anti-icing film model was studied by means of test optimization and test. The variance analysis, the verification of the optimal film coating model and the simulation of the actual natural environment icing test were carried out. It is found that the primary and secondary factors affecting the freezing tangential force are the deep pit diameter of the low freezing solution concentration. When the concentration of ethanol solution is 6 mm, the diameter of the pit is 22 mm, and the depth of the pit is 4.7mm, the model of anti-icing coating is the best, and the effect of reducing the tangential adhesion strength of ice is the best. After the application of the optimal anti-icing film model, the tangential adhesion strength of the ice can be reduced to 56.36 for the water with impurity content of 0.08g/m L. The lower the impurity content, the better the effect of the film mulching model on reducing the ice tangential adhesion strength.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O552.6

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