【作者】 安萍；

【导师】 李劲；

【作者基本信息】 华中科技大学 ， 环境工程， 2004， 硕士

【摘要】 气固混和两相体放电现象的研究既可以为了解气固混和两相体的绝缘特性和击穿过程提供理论依据,也可以为多相体放电在环境治理、等离子体等新技术应用方面提供实验和理论基础。但目前以气固两相体为对象的放电基础研究,国内外尚未进行系统的试验观测。本文通过大量试验,初步研究了非均匀电场中,放电间隙较小的流化床状态和间隙较大的静止状态下几种气固混和两相体放电发生、击穿的基本特性和影响因素。为进一步研究非均匀电场中气固两相体放电的物理性质和数学建模提供了初步的实验依据。实验具体研究了非均匀电场中交/直流电压下,电压极性、间隙距离、固相物介电常数和占空比对气固混和两相体放电的影响。结果表明:1. 放电间隙较小的流化床状态下,两种气固混合两相体的击穿电压都低于相同条件下单一空气的,相对介电常数大的混合两相体较易击穿。其直流击穿特性具有“极性效应”,正极性击穿电压低于负极性。固体颗粒对电场的畸变作用可能是影响击穿的主要因素。2. 放电间隙较大的静止状态下,直流电压正极性和交流电压下气固混合两相体的击穿电压都大于相同条件下单一空气的,而直流电压负极性时则相反。和正极性相比,负极性时混合体更易击穿。占空比大的气固两相体击穿电压总是小于占空比小的。颗粒荷电畸变电场以及对放电通道的阻挡可能是影响此放电的主要因素。最后,本文在已做工作的基础上提出了气固两相体击穿特性实验研究方面需进一步解决的问题。更多还原

【Abstract】 The research on discharge in a two-phase mixture of gas and solid can give theoretical basic on its insulation characteristics and discharge process, as well as experimental background of its application on environment treatments and plasma technology and so on. But up to now, the basic research on this has not been observed systematically both at home and abroad. In this paper, the AC/DC breakdown characteristics and influence factors of several two-phase mixtures of gas and solid have been studied through a large amount of experiments in the nonuniform electric fields. The experiments were tested in both fluidized bed with short discharge interval and inactive state with long discharge interval. It has offered the preliminary experimental basis for the physical property and mathemetics modeling of the two-phase mixture of gas and solid.The effects of the voltage polarity, discharge interval, permittivity and volume ratio of solid dielectrics were investigated and analyzed under AC/DC voltage in the nonuniform electric fields. Experimental results show that: In the state of the fluidized bed, the breakdown voltage of all mixtures were lower than the single air in the same conditions, and it was breakdown more easily in which the permittivity value of solid dielectrics was higher. The positive breakdown voltage is below the negative under DC voltage. It was the main factors affecting the breakdown that the solid particles deformed electric field. In the in- active state, the breakdown voltage were higher than the single air in the same conditions under AC and positive DC voltage, but it was opposite under negative DC voltage. So the two-phase mixtures of gas and solid were breakdown more easily when the polarity was negative under DC voltage. And the breakdown voltage of the two-phase mixtures of gas and solid was lower, which volume ratio of solid dielectrics was larger. It was the main factors affecting the breakdown that the charged solid particles deformed electric field and blocked the discharge path. At last, the problems about discharge experiments of the two-phase mixtures of gas and solid that need to be solved deeply in further were presented.更多还原