基于近壁热源上方热羽流贴附效应的竖壁颗粒沉积机理研究

The rapid and heavy particle deposition on vertical walls with the attached effect of thermal plumes above near-wall heat sources, which widely exists in indoor environments, has an important direct effect on the human health, public safety, electronics manufacturing, treasure protection and so on. However, the mechanism and formation condition of this particle deposition phenomenon are not yet fully known. A targeted judgment method of the particle deposition conditions needs to be proposed. This phenomenon hasn’t been well used in the particle removal and the contamination control. Therefore, it’s necessary to study the mechanism of this kind of particle deposition. This project adopts the experimental method, numerical simulation, theoretical analysis and measurement to study the particle deposition influenced by thermal plumes. The particle distributions above near-wall heat sources are explored. Furthermore, the major influence factors and formation conditions of the particle deposition on the vertical walls above near-wall heat sources are discussed. Also, the movement and the forces on particles are analyzed. The leading role in the particle deposition is determined as well as the precise and suitable prediction model for the particle deposition above near-wall heat sources is established. This project will reveal the particle deposition mechanism and provide the scientific basis for controlling the suspended particles by thermal plumes and reducing the harmful particle deposition, which has an important theoretical and practical significance.

近壁热源上方热羽流贴附效应作用下颗粒在温度较低竖壁上快速、大量沉积对人体健康、公众安全、电子制造、珍品保护等有直接且重要的影响。这种沉积现象广泛存在，但作用机理和形成条件尚未明确，有针对性的沉积状况评判方法有待提出，难以实现其在颗粒脱除及污染控制方面的应用，因此非常有必要对此种颗粒沉积的机理进行深入研究。本项目拟通过实验测试、数值模拟、理论分析及现场实测相结合的方法，得到热羽流贴附效应作用下的颗粒分布特性；探明竖壁颗粒沉积的主要影响因素，提出快速、大量沉积形成条件的定量化描述，揭示颗粒沉积形成机制；分析颗粒运动及受力情况，确定颗粒受到的主导作用，建立基于热羽流作用特性且考虑主要影响因素的精准、适用的颗粒沉积预测模型。研究成果有望解决束缚热羽流贴附效应作用下的颗粒沉积走向应用的关键机理问题，为利用热羽流贴附效应改善颗粒悬浮状况及减少颗粒有害沉积提供科学依据，具有重要的理论意义和工程应用价值。

近壁热源上方热羽流贴附效应作用下颗粒在温度较低竖壁上快速、大量沉积是普遍存在的物理现象。深入研究此种沉积的作用机理，可为利用热羽流贴附效应改善颗粒悬浮状况及减少颗粒有害沉积提供科学依据。本项目通过试验测试、数值模拟、理论分析及现场实测相结合的方法，分析了羽流参数、颗粒特性等变化时近壁热源上方颗粒物浓度与粒径分布特性；追踪了颗粒在热羽流贴附效应作用下的运动轨迹，进行了颗粒受力分析，探明了竖壁颗粒沉积的主要影响因素，揭示了颗粒沉积机理；在颗粒沉积机理分析的基础上，建立了基于热羽流作用特性且考虑主要影响因素的颗粒沉积预测模型。该研究为发展热羽流脱除悬浮颗粒技术及解决相关的颗粒有害沉积问题提供了理论支持和技术保障。