摘要
相变—通风混合冷却服中两种介质之间存在相互影响,作用机制复杂。本文从冷却介质、服装、人体和环境四个方面剖析了影响冷却效果和着装热湿舒适性的关键因素,发现各因素对冷却效果的交互影响还未得到细化研究,且忽视了服用性能方面的影响。同时,分析了不同测评方法在相变—通风混合冷却服中应用时的适用性及局限性,研究表明物理实验采用的方法、程序和指标的不同会影响测评结果,数值模型存在简化热湿传递和通风过程等不足。本文提出未来的研究可以综合考虑多方面因素对冷却效果的交互影响,探寻兼顾冷却和服用性能的冷却服参数设计;对冷却效果的测评则应考虑建立更加标准化的物理实验测试方法与综合评价体系,并完善对衣下空气层形态、空气流动及热湿传递过程的数值模拟。
Since ambient cooling measures cannot be used in some special high temperature environments,researchers have developed various cooling garments with different cooling mechanisms.Among them,the cooling clothing of phase change materials(PCMs)and ventilation fans has gradually attracted more researchers’attention due to its advantages of energy saving and renewability.Therefore,the hybrid cooling clothing(HCC)based on PCMs and ventilation fans has been developed to improve the comprehensive cooling effect.However,when two kinds of cooling media coexist,the cooling effect is not only simple superposition,but also complex interaction is produced.In recent years,researchers have compared the working mechanism,advantages and disadvantages,and applicable conditions of the two cooling media,and explored the influence mechanism of factors such as human body,cooling clothing and environment on the cooling effect.However,the cooling mechanism of the HCC under the influence of multiple factors has not been deeply revealed,which also affects the establishment of targeted evaluation methods.Firstly,the key factors affecting the cooling effect are analyzed from the aspects of cooling medium,clothing,human body and environment.The cooling medium has the most direct influence on the cooling effect.The melting temperature,addition amount and distribution mode of PCMs are the main factors affecting the endothermic effect.The air flow volume and placement of the ventilation fans are the main factors affecting the convection and evaporative effect.And the cooling strategy of the HCC affects the cooling efficiency.Heat transfer from the environment to the human body and PCMs during ventilation can be reduced by running the fan after the amount of sweating increases,or by adding insulation layer.And after PCMs are completely melted,it is removed in time to reduce the physiological load and improve the moisture permeability of the clothing.In addition,the opening and fit of clothing and the motion state of human body indirectly affect the air exchange between microclimate and environment during ventilation,as well as the air flow and heat transfer mode within microclimate.And then,the level of human activity directly determines the amount of metabolic heat and sweat production,the ambient temperature and humidity affect the direction of heat and moisture transfer between human body,clothing and environment,thus affecting the applicability of the cooling media.On the basis of the influencing factors,the differences and limitations of using different methods to evaluate the cooling effect are further analyzed.Thermal manikin tests are a general method to evaluate the thermal insulation and moisture permeability performance of clothing.However,existing studies often ignore the influence of the motion state on the cooling effect when using this method.And this method cannot fully simulate the physiological characteristics,heat transfer behavior and movement limitation of the clothed human body.The human test directly quantifies the cooling effect by collecting the subjects’physiological indicators and subjective evaluation.However,the research object,test procedure and evaluation index of the human test still need to be normalized.The mathematical modeling approach can predict the heat and moisture transfer process by integrating the heat and moisture transfer model of the cooling clothing and the human thermophysiological model.And the optimal design parameters and working modes of cooling clothing under different conditions can be studied by modifying the model settings.However,most of the existing heat and moisture transfer models of cooling clothing are one-dimensional models which oversimplify the heat and moisture transfer and ventilation process.When only PCMs or ventilation fans are used as the cooling media,their respective defects will have a negative impact on the cooling effect.When the two cooling media are used together,not only the cumulative effect of the cooling effect can be produced,but also the interaction of complementary advantages can be generated.At present,the HCC based on PCMs and ventilation fans has become a hot research topic.Through in-depth study of the influence mechanism of various factors on the cooling effect,we optimize the parameter design of HCC.In this way,the cooling effect can be improved to ensure the thermal safety of operators in high temperature environment.The results show that:(i)the interaction of various factors on the cooling effect has not been researched in detail,and the influence of cooling medium design on the movement flexibility,thermal comfort uniformity and other wearability is ignored.(ii)The different methods,procedures and indexes used in physical experiments will affect the evaluation results,and the numerical model has defects such as simplifying heat and moisture transfer and ventilation process.The future development trend is to comprehensively consider the interaction of various factors on the cooling effect,and further explore the parameter design of cooling clothing that takes into account the cooling effect and wearability.For the evaluation of the cooling effect,a more standardized physical test method as well as a comprehensive evaluation system should be established,and the numerical simulation of air layer morphology,air flow and heat and moisture transfer process should be established.
作者
吴珺秋
李俊
WU Junqiu;LI Jun(College of Fashion and Design,Donghua University,Shanghai 200051,China;Key Laboratory of Clothing Design and Technology,Ministry of Education,Shanghai 200051,China;Shanghai Belt and Road Joint Laboratoryof Textile Intelligent Manufacturing,Shanghai 200051,China)
出处
《丝绸》
CAS
CSCD
北大核心
2023年第4期71-79,共9页
Journal of Silk
基金
中央高校基本科研业务费专项资金资助项目(2232022G-08)
上海市科学技术委员会“科技创新行动计划”“一带一路”国际合作项目(21130750100)。
关键词
相变材料
通风风扇
混合冷却服
冷却效果
影响因素
测评
phase change material
ventilation fan
hybrid cooling clothing
cooling effect
influencing factors
test and evaluation
作者简介
吴珺秋(1998),女,硕士研究生,研究方向为服装舒适性与功能防护服装;通信作者:李俊,教授,lijun@dhu.edu.cn。
