Research On The Performance Of A Two-Stage Electrostatic Precipitator Used In Air Cleaners And The Application Of Cleaners

With the development of economy, science, technology, and the improvement of people's living standard, the requirement of health living is becoming more and more important. Generally, one person spends most of his time in houses. The IAQ (indoor air quality) condition has a direct influence on the health of human beings. One of the main measures of improving IAQ is to control contamination sources strictly Electrostatic air cleaners are a type of purifying equipment widely used to remove indoor air contaminants.PM₁₀ is one of the primary air contaminants worsening indoor air quality. Therefore, most of countries in the world have established indoor air quality standards to limit the concentration of PM₁₀ or PM_2.5. Currently, electrostatic air cleaners on the market are usually multifunctional, and the chief components to catch particles used in cleaners are electrostatic precipitators. Compared to many other dust catchers, electrostatic precipitators are characterized by lower running pressure drop, less operation cost and higher filtration efficiency to fine particles. In this paper, the effects of the main geometric and operational parameters on the performance of a two-stage plate-type electrostatic precipitator were evaluated by integrated experimental study and theoretical analysis. Some suggestions on the design and improvement ofsuch electrostatic precipitator were put into recommendation. This paper indicated that thinner discharge wires at charging zone of the two-stage electrostatic precipitator are preferable when which stress intensity is insured. The charging time for particles should be taken into account, and effective length of charging zone had better be adequate for particles have enough charge time. Commonly, in one channel of the two-stage electrostatic precipitator, only one discharge wire might result in deficiency of electric charge on particles, two or more wires could improve the performance of charging particles. However, the space between discharge wires had better be a little longer than the space between plates. Any way, the main geometric and operational parameters that would affect the performance of such electrostatic precipitator should be considered integrally and practically.An individual room with an air cleaner placed in was studied. The paper analyzed the variation expression of particle concentration when an air cleaner keeps running in the room. On the basis of that, the evaluation standards of air cleaners are discussed and some opinions are posed for more reasonable evaluation methods. In addition, with the head evaluation index in the standards, it was discussed that how to determine the magnitude of an air cleaner for a room, and air flow rate for electrostatic precipitators used in air cleaners.New designs on several types of electrostatic air cleaners in common use were put forward. And we have employed CFD (Computational Fluid Dynamics)method to simulate the indoor velocity field and the concentration field of particles when the cleaner keeps running in the room. Through the analysis of the simulation, it is shown that air distribution has a great impact on running effects of indoor aircleaners. The magnitude and direction of supplying air velocity of cleaners should be chosen reasonably to avoid airflow short and reduce draft risk. At given occasions, it is important to select right types of air cleaners and locate them correctly. The impact of airflow from other sources should be taken into account. When air cleaners run, it is efficient if persons stay at the place where supplying air from cleaners can reach and particles emitted by dust sources could be transported straightway into air cleaners which could cut down the particles diffusing to other regions of the room.Cheng Dengta(Heating, Ventilation and Air Conditioning)Supervised by Associate Prof. Liu Gan...