介质阻挡放电臭氧发生的传热模拟和产生机理初探

发布时间：2018-05-13 07:17

本文选题：臭氧 + 介质阻挡　；参考：《南昌大学》2015年硕士论文

【摘要】：臭氧是氧的同素异形体,在常温下,它是一种有特殊臭味的蓝色气体。臭氧具有强氧化性,且没有二次污染,应用前景诱人。但是臭氧产生是一个高耗低效过程,放电法产生臭氧所消耗的大部分电能转化为热量散发出去,这部分热量会促使放电空间温度升高,进而分解产生的臭氧。因此臭氧发生器放电室温度分布显得至关重要。本文采用数值模拟手段对脉冲介质阻挡放电臭氧放电室进行传热模拟,并尝试探索介质阻挡放电的反应机理。模拟分析结果如下:(1)氧气进入放电空间后,气体温度变化规律为:温度沿着横向上升,到达出口处气体平均温度略微降低,因为随着反应的进行,电极通过热传递给气体,到达出口处,气体与室外连通,所以温度先逐渐升高,后略微降低。此外,气体间隙温度沿着纵向逐渐升高,到达底部升高明显。由于有电介质一端电极不易散热,电介质导热性能差,导致温度较高。有散热片加大了散热面积,电极把热量通过热传导传递给铝散热片,有利于气体间隙的温度降低。不同氧气进气速度与气体间隙平均温度存在着一定关系,提高流体的流速能有效的改善其散热效果。通过改变橡胶厚度,提高放电宽度,降低放电空间的温度。通过加风扇,对臭氧发生器的外部空气强制对流换热,也能明显的降低气体间隙平均温度。(2)在圆筒形臭氧发生器中,臭氧浓度在放电的初始阶段呈现快速增长,达到峰值后,由于放电间隙中化学反应放出的热量难以排出,放电室中的温度升高,使得生成的臭氧部分分解,臭氧浓度开始下降,直到臭氧的生成速率和分解速率达到平衡,臭氧浓度不再发生变化,达到稳定值。高压电极和低压电极附近的氧原子浓度远低于放电间隙中心处的氧原子浓度,其在放电间隙中心处达到峰值,中心两边氧原子浓度基本呈对称分布且随距离的增加而逐渐减小,在电极附近达到最小值。
[Abstract]:Ozone is an oxygen isomorphism. At room temperature, it is a blue gas with a special odor. Ozone has strong oxidation and no secondary pollution, so its application prospect is attractive. However, ozone generation is a high-consumption and low-efficiency process. Most of the electricity consumed by the discharge process is converted into heat, which will cause the temperature of the discharge space to rise and then decompose the resulting ozone. Therefore, the temperature distribution in the discharge chamber of ozone generator is very important. In this paper, the numerical simulation method is used to simulate the heat transfer in the pulsed dielectric barrier discharge ozone chamber, and the reaction mechanism of the dielectric barrier discharge is explored. The simulation results are as follows: 1) when oxygen enters the discharge space, the gas temperature changes as follows: the temperature rises horizontally, and the average temperature of the gas reaches the outlet slightly lower, because as the reaction proceeds, the electrode transmits heat to the gas. At the exit, the gas is connected to the outside, so the temperature rises gradually and then drops slightly. In addition, the gas gap temperature increases gradually along the longitudinal direction, and increases obviously at the bottom. Because the dielectric electrode is not easy to dissipate heat, the dielectric thermal conductivity is poor, resulting in higher temperature. The radiator increases the radiating area, and the electrode transfers heat through heat conduction to the aluminum radiator, which is favorable to the decrease of the temperature of the gas gap. There is a certain relationship between the oxygen inlet velocity and the average temperature of the gas gap. Increasing the flow velocity of the fluid can effectively improve the heat dissipation effect. By changing the thickness of rubber, the discharge width is increased and the temperature of discharge space is reduced. By adding fans, the forced convection heat transfer of the external air of the ozone generator can also significantly reduce the average temperature of the gas gap. In the cylindrical ozone generator, the ozone concentration increases rapidly in the initial stage of the discharge and reaches the peak value. Because the heat released by chemical reaction in the discharge gap is difficult to excrete, and the temperature in the discharge chamber rises, the ozone produced partially decomposes, and the ozone concentration begins to decrease, until the formation rate and decomposition rate of ozone reach equilibrium. Ozone concentration does not change again, reaching a stable value. The oxygen atom concentration near the high voltage electrode and low pressure electrode is much lower than that at the center of the discharge gap, and it reaches the peak value at the center of the discharge gap. The oxygen atom concentration on both sides of the center is symmetrical distribution and decreases gradually with the increase of distance. The minimum value is reached near the electrode.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ123.2

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