摩擦电除尘及汽车尾气过滤技术研究

In an automobile, the removal of the particulate matters (PMs) from exhaust by harvesting the mechanical energy of the tailpipe using the triboelectrification effect is of great importance in both academia and industry. This project objective is to develop a new triboelectric filter based on the vibration triboelectric nanogenerator (V-TENG). By using the natural vibration of the tailpipe and the movement of the exhaust fumes, a high electric field on the order of ~MV/m can be generated between the dielectric materials and electrodes. Therefore, a composite mechanism of electrostatic filtration and mechanical filtration was first proposed to reveal the removal mechanism of the PMs. For the electrostatic filtration, using the generated high electric field, the charged particles in the exhaust fumes will be deposited on the electrodes and/or dielectric materials by the electrostatic force; as for mechanical filtration, when the suspended particles flow through the triboelectric filter the particles can be attracted to the surface of dielectric materials by interception, inertial impaction, diffusion, and gravitation settling due to various forces, such as van der Waals force, capillary force, and gravity. In order to further improve the collection efficiency, we will elucidate the mechanism of the filtration processes, and optimize the design of the triboelectric filter using the aerodynamics and finite element simulation; in addition, we will develop the prototype of the triboelectric filter that is compatible with the gasoline cars. The research of this project has significant importance in revealing the mechanism of the triboelectric filter and improving the collection efficiency of PMs. The development of the triboelectric filter also has great impact on the environmental improvement.

通过收集汽车发动机工作过程中尾气管的机械能产生电能，来实现对汽车尾气中颗粒物的高效过滤，对治理汽车尾气污染具有重要的科学意义和应用价值。本项目在震动型摩擦纳米发电机（TENG）基础上研制新型摩擦电过滤器，研究利用汽油车尾气管的机械震动和气流动能，使TENG内部介质材料与金属极板相互碰撞摩擦，产生高压电场（>MV/m），构筑摩擦电除尘和物理过滤除尘的复合除尘机制，即：利用带电极板和带电介质间高压电场实现对尾气中带电颗粒物的静电吸附；利用介质材料对颗粒物的惯性拦截、碰撞、扩散、重力沉降等作用实现对汽油车尾气中非带电颗粒物的物理吸附。结合流体力学和有限元分析，探索过滤机理，优化器件结构，提高过滤效率，研制与汽油车排气管（或底盘）相兼容的摩擦电过滤器工程样机，实现对汽车尾气中颗粒物的高效过滤。本项目研究工作对揭示摩擦电除尘机理、提高摩擦电除尘效率和探索摩擦电除尘技术在环境治理中的应用具有重要意义。

本项目利用摩擦纳米发电原理，通过收集汽车发动机在工作过程中尾气管的机械能产生高强摩擦电场，来实现对汽车尾气中颗粒物的高效过滤，对治理汽车尾气污染具有重要的科学意义和应用价值。本项目主要针对震动型摩擦纳米发电机（TENG）及其利用该技术制备的摩擦电空气净化器的材料选取、材料表征&性能测试以及汽车尾气过滤器的器件设计、性能测试、理论模拟与计算、机理分析、工程样机制备及其综合性能测试与评价等开展一系列的研究工作。所制备的摩擦电汽车尾气过滤器，能够利用汽车尾气震动产生MV/m及以上的电场，对汽车尾气中的颗粒物（主要粒径分布在20⁓100 nm）能够实现90%的高效过滤；所制备的工程样机，在别克凯越汽车上进行连续工况测试，能够将其尾气中的颗粒物有初始的1300 μg/m3降低至10 μg/m3以下，且连续运行5000公里无明显衰减。该研究对开发新型汽车尾气过滤器及减少汽车尾气污染等方面具有重要的科学意义和应用价值。