渗流射流耦合作用下纤维空调末端气流流动规律与换热机制

As a flexible air-conditioning strategy, the conditioned airflow through fabric air dispersion system (FADS) is characterized with the coupling of percolation and jet flow, which may create clean and comfortable indoor air environment. However, the mechanism of flow and heat transfer is still seldom known. Based on the previous work, by the method of theory analysis and on-spot experiment, the project will determine the fibre shape factors, and develop the theoretical model of flow and heat transfer of conditioned airflow through FADS based on the revised Carman-Kozeny equation. Combined with the Particle Image Velocimetry (PIV) technology，the project will explore the charateristics of air flow distribution within non-continuous physical regions, the FADS' cavity-fibre layer-other regions inside room. And, the project will study the influence of properties of fibre physical configuration and artificial orifice on the flow resistance, the distribution of air velocity and termperature, and then establish the interior mathematical relation of properties of fibre physical configuration and artificial orifice with the ratio of percolation flowrate to jet flowrate, indoor airflow organization and thermal comfort indexes (PMV, PPD). Furthermore, the project will reveal the mechanism of flow and heat transfer of conditioned airflow through FADS by the coupling of percolation and jet flow. Research results will provide the theoretical basis for optimizing FADS' configuration and putting forward a universal method of designing orifice, and would have an important academic value and practical significance for the development of the strategy of flexible air-conditioning based on FADS.

作为一种柔性空调技术，基于纤维空气分布系统的空调气流具有渗流与射流耦合流动特征，能创造洁净舒适的室内微气候环境。然而，其流动规律及换热机制尚不清楚。本项目旨在现有研究基础上，通过理论分析和现场实验方法，确定纤维结构形状因子，修正Carman-Kozeny方程，建立基于纤维空气分布系统的空调气流流动与换热理论模型；结合PIV技术,研究纤维空气分布系统空腔-纤维结构层-室内其他区域等非连续结构区域内耦合气流场特征，研究纤维物理结构、小孔特性对流动阻力、速度和温度分布的影响，建立其和空气渗透流量与射流流量的分配比、室内气流组织以及PMV和PPD等热舒适指标之间的内在数学关系，揭示渗流射流耦合作用下基于纤维空气分布系统的空调气流流动规律与换热机制，为纤维空气分布系统的结构优化和提出具有普适性的小孔设计方法奠定理论基础，对发展基于纤维空气分布系统的柔性空调技术具有重要的学术价值和实际工程意义。

纤维空气分布系统作为一种柔性空调末端装置，能创造洁净舒适的室内微气候环境。本项目在已有研究基础上，通过理论分析和现场实验方法，研究了空气流动规律及换热机制。主要研究成果具体如下：.① 测量了纤维结构物理特性，修正了适合于描述纤维特性的Carman-Kozeny方程,建立了能有效描述基于纤维空气分布系统的空调气流流动与换热特性的理论模型。.② 进一步证实了直接描述法描述条缝式纤维空气分布系统物理模型的可信性，同时提出和验证了适应于工程中快速预测气流流态的两种纤维空气分布系统简化描述方法，即平均流速法和自由（有效）面积法。.③ 空气进入条缝式纤维空气分系统后，首先充满整个空腔，然后在静压的作用下从纤维孔隙和孔口流出。各股射流流态相似，到达一定射程后开始掺混，形成类似条缝式的气流。空腔中心区域空气以较高的速度向前流动，速度越来越小，总压逐渐降低，静压逐渐增大，但二者的梯度均越来越小；靠近纤维壁面区域空气流向逐渐改变，最终沿垂直于纤维壁面的方向，从纤维孔隙和小孔向外流出；空腔内部为静压区，总压和动压呈辐射状向四周递减。.④ 空腔内部空气总压和静压随孔隙率或孔距的增加而增加，随孔径的增加而降低，动压基本不变；孔口射流流速则随孔距的增加而增大，随孔径和孔隙率的增加而降低；孔隙率的增加使得空气渗透流量与孔口射流流量的分配比增加。.⑤ 室内热舒适性指标PPD受纤维风管长度影响较大，而受孔距和孔径的影响相对较小，y=1.7m高度处舒适性较其他平面相对较差。