基于Smith模型的三维有限元人体热调节模型

发布时间：2018-09-14 09:41

【摘要】： 随着能源紧张问题日益突出,如何降低占有社会商品能源三分一的建筑能耗成为目前暖通空调领域亟待解决的主要问题之一。因此如何在保证热舒适的同时实现建筑节能成为一个热点研究方向。数值人体热调节模型在暖通空调领域的使用能够很大地促进室内人工环境的营造理论和热舒适理论的研究,并且为工程实际提供预测工具,是目前国际前沿的研究领域。本文研究旨在以建立适合暖通空调领域研究使用数值人体模型为目标,综合当前所有模型的优秀思想和方法,建立合理的生理模型和数学模型,并且开发了一套高效的求解程序。数值热调节模型的建立主要包括三个部分:生理模型、数学模型和程序开发。前两者由两个子系统组成,即受控系统和控制系统,包括物理人体本身和出汗、寒战、新陈代谢、血管舒缩等子调节模型。本文分析研究人体各种生理现象,在Smith模型的基础上建立了16节段、66层和一个中心血液节点的多元模型,有如下结论: 首先,本文分析了Smith血液模型对四肢皮肤温度预测不准确的原因,改进了Smith模型的皮肤层血液灌注率控制模型,借鉴Fiala血液模型建立了内部各层的血液灌注率模型,实验证明对四肢尤其是手和脚部位的皮肤温度的预测精度有明显的提高。其次,针对目前热调节模型的复杂性带来的改变服装形式和改进服装模型的困难较大的问题,本课题提出将环境对人体的所有热湿影响抽象为皮肤表面的第二类换热现象的新方法,提高了模型的灵活性并且扩展了其使用范围。第三,本文定量分析了各种出汗因素对平均皮肤温度的影响,引入Shitzer的出汗阀值模型,并对Smith出汗模型的参数进行了修正。本文指出了Smith模型中假设新陈代谢率为定值的不足之处,引入了Fiala的动态新陈代谢模型和寒战模型。第四,本文对比分析了当前模型采用的人体参数,发现不同模型采用的人体参数的差别一般在30%左右。由参数敏感性分析可知,皮肤血液灌注率的变化对人体热调节功能影响特别大,几何尺寸对皮肤温度的影响较大,整体血液灌注率和辐射系数在10%左右变化量对皮肤温度的影响有限。最后,本课题使用有限元方法开发了全套数值人体热调节模型代码。本文采用了Abdul Munir系列动态实验、Shengwei Zhu的实验以及大连理工大学热舒适小组的实验结果进行对比分析。实验证明本模型有效解决Smith模型对手和足模拟不准确的问题,对均匀稳态和非均匀非稳态工况下人体皮肤温度的动态变化的预测精度都有明显的提高,能够满足暖通空调领域的应用。
[Abstract]:With the problem of energy shortage becoming more and more prominent, how to reduce the building energy consumption, which occupies one-third of the social commodity energy, has become one of the main problems to be solved urgently in the field of HVAC. Therefore, how to ensure thermal comfort while building energy conservation has become a hot research direction. The application of numerical human thermal regulation model in the field of HVAC can greatly promote the study of indoor artificial environment theory and thermal comfort theory, and provide a prediction tool for engineering practice. It is a frontier research field in the world at present. The purpose of this paper is to establish a numerical mannequin model suitable for the research of HVAC field, to synthesize the excellent ideas and methods of all the current models, and to establish reasonable physiological and mathematical models. And developed a set of efficient solution program. The establishment of numerical heat regulation model includes three parts: physiological model, mathematical model and program development. The former two are composed of two subsystems, namely, the controlled system and the control system, including the physical human body itself and the models of sweating, shivering, metabolism, vasomotor and contraction and so on. In this paper, we analyze and study various physiological phenomena in human body. Based on the Smith model, we establish a multivariate model of 16 segments and 66 layers and a central blood node. The conclusions are as follows: first of all, This paper analyzes the reason why Smith blood model is inaccurate to predict the skin temperature of extremities, improves the control model of blood perfusion rate in skin layer of Smith model, and establishes the blood perfusion rate model of each layer of interior by using Fiala blood model as reference. The experimental results show that the prediction accuracy of skin temperature in extremities, especially in hands and feet, is significantly improved. Secondly, in view of the complexity of the current thermal regulation model, it is difficult to change the clothing form and improve the clothing model. In this paper, a new method is proposed to abstract all the heat and moisture effects of the environment to the second kind of heat transfer phenomenon on the skin surface, which improves the flexibility of the model and expands its application scope. Thirdly, the effects of various sweating factors on the average skin temperature are quantitatively analyzed, and the Shitzer's sweating threshold model is introduced, and the parameters of the Smith sweating model are modified. This paper points out the deficiency of Smith model which assumes that the metabolism rate is constant, and introduces the dynamic metabolism model and shivering model of Fiala. Fourthly, this paper compares and analyzes the human body parameters used in the current model, and finds that the difference of the human body parameters used in different models is generally about 30%. According to the parameter sensitivity analysis, the change of the skin blood perfusion rate has a great influence on the human body's thermal regulation function, and the geometric size has a great influence on the skin temperature. The whole blood perfusion rate and radiation coefficient about 10% have a limited effect on skin temperature. Finally, a complete set of code of numerical human body thermal regulation model is developed by using finite element method. In this paper, the experimental results of Abdul Munir series dynamic experiment and thermal comfort group of Dalian University of Technology are compared and analyzed. The experiments show that the model can effectively solve the problem of imaccuracy in the simulation of the opponent and foot of the Smith model, and improve the prediction accuracy of the dynamic changes of human skin temperature under the uniform steady and non-uniform unsteady conditions. Can meet the application of HVAC field.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：R311

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